Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Science in Semiconductor Processing  

For the mass production of highly sensitive CMOS image sensors, the development of a high-performance gettering technique, which can remove metallic impurity contaminations from device active region with a low-concentration impurity such as carbon or oxygen is required. To address this issue, we developed a hydrocarbon (C<inf>2</inf>H<inf>x</inf>⁺) and silicon-hydride (SiH<inf>y</inf>⁺) mixture molecular ion implantation technique to form a gettering sink even under low carbon doses. However, the influence of carbon on gettering behavior in the molecular-ion-implanted region has never been investigated. In this study, we investigated the influence of the C<inf>2</inf>H<inf>x</inf>⁺ ratio on the gettering behavior in the molecular-ion-implantation region by changing the cooling method in Ni contamination diffusion heat treatment between quenching and slow cooling. As a result, we clarified that the gettering behavior is dependent on the defect type that changes depending on the C<inf>2</inf>H<inf>x</inf>⁺ ratio. These results suggest that mixture molecular ion implantation is effective in designing the gettering sinks via the changes in C<inf>2</inf>H<inf>x</inf>⁺ ratio.

DOI： 10.1016/j.mssp.2024.108226

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ecs Journal of Solid State Science and Technology  

The reduction in SiO<inf>2</inf>/Si interface state density (D<inf>it</inf>) at the SiO<inf>2</inf>/Si interface region is important to improve the performance of complementary metal-oxide semiconductor (CMOS) image sensors. The CH<inf>3</inf>O-ion-implanted region stores hydrogen and releases the stored hydrogen during the subsequent heat treatment. This study demonstrates that a CH<inf>3</inf>O-ion-implanted epitaxial silicon wafer can reduce the D<inf>it</inf> and Pb<inf>0</inf> center density in SiO<inf>2</inf>/Si interface regions, as analyzed by quasi-static capacitance-voltage and electron spin resonance measurements, respectively. Both D<inf>it</inf> and Pb<inf>0</inf> center density in the CH<inf>3</inf>O-implanted wafer decreased with increasing heat treatment temperature. Moreover, the activation energy is estimated to be 1.57 eV for the hydrogen termination reactions induced by the CH<inf>3</inf>O-ion-implanted wafer. The activation energy is close to those of hydrogen molecules and Si dangling bonds at the SiO<inf>2</inf>/Si interface. This result means that D<inf>it</inf> can be reduced by hydrogen from inside the silicon wafer, regardless of the heat treatment atmosphere. It has unique characteristics not found in conventional silicon wafers. The termination effect of the CH<inf>3</inf>O-molecular-ion-implanted epitaxial silicon wafers can contribute to the high electrical performance of CMOS image sensors.

DOI： 10.1149/2162-8777/ad1c88

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：2023 21st International Workshop on Junction Technology IWJT 2023  

DOI： 10.23919/IWJT59028.2023.10175180

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：2023 21st International Workshop on Junction Technology IWJT 2023  

DOI： 10.23919/IWJT59028.2023.10175104

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：2023 21st International Workshop on Junction Technology IWJT 2023  

DOI： 10.23919/IWJT59028.2023.10175183

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We propose the use of a laminated wafer with a conductive diamond layer for forming cavities as an alternative silicon-on-insulator wafer for micro-electro mechanical system (MEMS) sensors. Since this wafer has no insulator such as a buried oxide (BOX) layer but a conductive layer, it is not charged during plasma treatment in MEMS sensor fabrication processes. The conductive diamond layer was formed on a base wafer doped with boron of more than 2 × 1021 atoms cm-3 by microwave-plasma-enhanced chemical vapor deposition. The resistivity of this layer was 0.025 ω cm, and this layer can be selectively etched to a base wafer made of silicon crystal, such as a BOX layer. In addition, a silicon wafer can be bonded to its layer without voids with gaps of more than 2 nm by surface-Activated bonding. Therefore, we believe that the laminated wafer studied here is useful for the fabrication processes for MEMS sensors that may otherwise be damaged by plasma treatment.

DOI： 10.35848/1347-4065/ac6056

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Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2022.1.0_2806

CiNii Research

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2022.1.0_2808

CiNii Research

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2022.1.0_2807

CiNii Research

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：20th International Workshop on Junction Technology IWJT 2021  

Complementary metal-oxide-semiconductor (CMOS) image sensors have widely been used in internet of thinking (IoT) devices such as smartphones, smart watch and personal computer tablets [1]. The consumer market strongly requires higher sensitivity and higher speed image data processing to realize high functional CMOS image sensors such as three dimensionally stacked back-side-illuminated CMOS image sensors (3D-CIS) [2]. However, there are some serious technological issues in the fabrication of advanced CMOS image sensors as shown in Fig. 1.

DOI： 10.23919/IWJT52818.2021.9609378

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：2017 IEEE Electron Devices Technology and Manufacturing Conference Edtm 2017 Proceedings  

CMOS image sensor has been widely used for ubiquitous devices. However, CMOS image sensor devices performance is dramatically influenced by process induced defects such as metallic impurities contamination at devices active region during CMOS devices process. Thus, it is extremely important to study metallic impurities influence on CMOS image sensor devices performance and to develop effectiveness metallic impurities gettering techniques. We introduce our new proximity gettering technique for advanced CMOS image sensor using carbon cluster ion implantation technique. Furthermore, we demonstrated that the carbon cluster ion implanted silicon wafer has high gettering capability of metal, oxygen and hydrogen impurity during CMOS image sensor devices fabrication process.

DOI： 10.1109/EDTM.2017.7947538

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Research Society Symposium Proceedings  

The Si(111) surface treated in NH<inf>4</inf>F has been investigated using photoemission and surface infrared spectroscopy (SIS). We confirm both with photoemission and SIS measurements that the NH<inf>4</inf>F-treated Si(111) surface is dominantly terminated with the monohydride Si (Si-H) oriented perpendicular to the surface and is free from silicon oxide. Photoemission and SIS data also demonstrate that ammonium fluorides react with the Si substrate to generate the hexafluorosilicate salt, (NH<inf>4</inf>)<inf>2</inf>SiF<inf>6</inf>. We propose that the formation of (NH<inf>4</inf>)<inf>2</inf>SiF<inf>6</inf> or SiF<inf>6</inf>^2- ions plays an important role in the NH<inf>4</inf>F etching of Si crystals.

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1557/PROC-315-505

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1109/JEDS.2025.3631002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE Journal of the Electron Devices Society  

We investigate the leakage current density- voltage (J-V) characteristics and gettering behavior of metallic impurities using a pn-junction diode fabricated with hydrocarbon (C3H5)-molecular-ion-implanted epitaxial silicon wafer. The pn-junction diode with C3H5 molecular ion implantation reduced the reverse leakage current. Additionally, metallic impurities such as Cu, Fe, and Au, identified by Deep level transient spectroscopy (DLTS) analysis, and oxygen dissolved in the silicon substrate were gettered in the C3H5-molecular-ion-implanted region. Furthermore, it became clear that the gettering behavior of metallic impurities and oxygen competes with one another during the pn-junction fabrication process. These findings suggest that lowering the oxygen concentration in silicon substrates improves the gettering capacity of metallic impurities.

DOI： 10.1109/JEDS.2025.3624795

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Crystals  

The surface recrystallization model of the fully amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted silicon (Si) substrate is investigated. Transmission electron microscopy is performed to observe the amorphous/crystalline interface near the C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate surface after the subsequent recovery thermal annealing treatment. At a depth of high-concentration carbon of approximately 4.8 × 10²⁰ atoms/cm³, recrystallization from the crystalline template to the surface by solid-phase epitaxial growth is partially delayed, and the activation energy was estimated to be 2.79 ± 0.14 eV. The change in the crystalline fraction of the fully amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate surface is quantitatively evaluated from the binding energy of Si 2p spectra by X-ray photoelectron spectroscopy. Using the Kolmogorov–Johnson–Mehl–Avrami equation, the surface recrystallization of the fully amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate is assumed to proceed two-dimensionally, and its activation energy is obtained as 2.71 ± 0.28 eV without the effect of carbon. Technology computer-aided design (TCAD) process simulations calculate recrystallization under the effect of high-concentration carbon and demonstrate the reach of some crystalline regions to the surface first. In the fully amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate, it is considered that recrystallization is partially delayed due to high-concentration carbon and surface recrystallization proceeds two-dimensionally from some crystalline regions reaching the surface first.

DOI： 10.3390/cryst14090748

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ecs Journal of Solid State Science and Technology  

Technology computer-aided design (TCAD) kinetic Monte Carlo simulations revealed the unique recrystallization processes of discrete amorphous regions connected to a buried amorphous layer in a C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted silicon (Si) substrate. The faithful simulation models show that the discrete amorphous regions are first recrystallized two-dimensionally in the lateral direction from both sides and separated from the buried amorphous layer. Then, the separated discrete amorphous regions are recrystallized three-dimensionally in the lateral and vertical directions from both sides and the bottom. We found that the first two-dimensional recrystallization of discrete amorphous regions is caused by the retardation of solid-phase epitaxial growth at the Si substrate surface and near the buried amorphous layer. We also found that the large (small) discrete amorphous regions require a long (short) two-dimensional recrystallization before separating from the buried amorphous layer. The transition point in the recrystallization dimension can be determined from the lateral recrystallization length and the equivalent radius of discrete amorphous regions.

DOI： 10.1149/2162-8777/ad3002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Crystals  

In this study, we investigate the initial rapid recrystallization of a discretely amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted silicon (Si) substrate surface in the subsequent thermal annealing treatment through the analysis of plan-view transmission electron microscopy (TEM) images and technology computer-aided design (TCAD) process simulation. In the approach of the analysis of the plan-view TEM image of the Si substrate surface, we found that initial rapid recrystallization occurs in the intermediate regions between the residual crystalline and discrete amorphous regions formed in the C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate surface. In addition, the TCAD process simulation results indicate that the intermediate regions correspond to the amorphous pockets formed around the discrete amorphous regions in the C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted Si substrate surface and are recrystallized preferentially during the short thermal annealing time. These plan-view TEM image analysis and TCAD process simulation results reveal a two-step recrystallization of the discretely amorphized C<inf>3</inf>H<inf>5</inf>-molecular-ion-implaned Si substrate surface. After the initial rapid recrystallization of amorphous pockets in the 1st step, the recrystallization of discrete amorphous regions starts in the 2nd step. The incubation period between the 1st and 2nd steps is the time required to recrystallize the amorphous pockets around the discrete amorphous regions completely and redefine the amorphous/crystalline interface.

DOI： 10.3390/cryst14020112

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Electrochemical Society  

Abstract

We investigated the thermal behavior of dislocation loops formed in a CH₃O-multielement-molecular-ion-implanted epitaxial silicon (Si) wafer by real-time cross-sectional tunneling electron microscopy observation with in situ heating. We found that the CH₃O-ion-implantation-induced faulted Frank dislocation loops (FDLs) shrink at a low rate at the beginning of heat treatment (1st stage), and then the shrinkage rate rapidly increased (2nd stage), resulting in the dissolution of the defects. The activation energies for the shrinkage of FDLs in the 1st and 2nd stages were found to be 2.94±0.31 and 4.95±0.25 eV, respectively. The shrinkage behavior in the 1st stage is the desorption of C and O atoms that segregated along the edge of an FDL because of the interaction between the CH3O-ion-implantation-induced FDL and the segregated impurities. On the other hand, the 2nd stage corresponds to the desorption of Si atoms from FDLs and its migration. Our experimental results suggest that thermal stability of the dislocation loop is determined by the kind of segregated impurities around the dislocation loop.

DOI： 10.1149/1945-7111/accd25

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Other Link： https://iopscience.iop.org/article/10.1149/1945-7111/accd25/pdf

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We investigated the recrystallization of discrete amorphous regions formed in a C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted silicon (Si) substrate surface in the rapid thermal annealing (RTA). The change in the crystalline fraction of the C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted substrate surface after the RTA was obtained from the chemical shifts of Si 2p spectra by X-ray photoelectron spectroscopy. We found that the crystalline fraction increases depending on the RTA temperature after an incubation period. The transformation from the amorphous phase to the crystalline phase was analyzed on the basis of the Johnson-Mehl-Avrami-Kolmogorov theory. It was revealed that recrystallization of discrete amorphous regions proceeded three-dimensionally and activation energy was estimated to be 2.74 ± 0.39 eV, which is approximately equal to 2.70 eV for the solid-phase epitaxy of the continuous amorphous layer in a Si crystal. Therefore, we believe that discrete amorphous regions are recrystallized via solid-phase epitaxy laterally and vertically from the amorphous/crystal interface around them.

DOI： 10.35848/1347-4065/ac97d5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Sensors  

Using a new implantation technique with multielement molecular ions consisting of carbon, hydrogen, and phosphorus, namely, CH<inf>2</inf>P molecular ions, we developed an epitaxial silicon wafer with proximity gettering sinks under the epitaxial silicon layer to improve the gettering capability for metallic impurities. A complementary metal-oxide-semiconductor (CMOS) image sensor fabricated with this novel epitaxial silicon wafer has a markedly reduced number of white spot defects, as determined by dark current spectroscopy (DCS). In addition, the amount of nickel impurities gettered in the CH<inf>2</inf>P-molecular-ion-implanted region of this CMOS image sensor is higher than that gettered in the C<inf>3</inf>H<inf>5</inf>-molecular-ion-implanted region; and this implanted region is formed by high-density black pointed defects and deactivated phosphorus after epitaxial growth. From the obtained results, the CH<inf>2</inf>P-molecular-ion-implanted region has two types of complexes acting as gettering sinks. One includes carbon-related complexes such as aggregated C–I, and the other includes phosphorus-related complexes such as P<inf>4</inf>–V. These complexes have a high binding energy to metallic impurities. Therefore, CH<inf>2</inf>P-molecular-ion-implanted epitaxial silicon wafers have a high gettering capability for metallic impurities and contribute to improving the device performance of CMOS image sensors. (This manuscript is an extension from a paper presented at the 6th IEEE Electron Devices Technology & Manufacturing Conference (EDTM 2022)).

DOI： 10.3390/s22218258

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of the Electrochemical Society  

The thermal stability of end-of-range (EOR) defects formed in a CH4N-molecular-ion-implanted epitaxial silicon (Si) wafer was studied by transmission electron microscopy (TEM) observation. By plan-view TEM observation, we found that the density and size of the CH4N-ion-implantation-induced EOR defects negligibly changed upon heat treatment at temperatures below 1000 °C, whereas the EOR defect density was drastically reduced by heating at 1100 °C. This result suggests that almost all CH4N-ion-implantation-induced EOR defects were sufficiently thermally stable to maintain their size at temperatures below 1000 °C, and that above 1100 °C, most of the EOR defects lost their stability, shrank and finally dissolved. Additionally, by in situ cross-sectional TEM observation during heat treatment, we found a large difference in the shrinkage rates of the EOR defects between at the beginning of heat treatment and the last minute of just before defect disappearance. We found that the EOR defects began to gradually shrank at the beginning of heat treatment (1st stage), and then the shrinkage rate rapidly increased (2nd stage), finally resulting in the dissolution of the defects. The activation energies for the shrinkage of EOR defects in the 1st and 2nd stages (ED-1 and ED-2) were found to be 7.55 1.03 and 4.57 0.32 eV, respectively. The shrinkage behavior in the 1st stage is likely to be due to the thermally activated desorption of C and N species that segregated along the edge of an EOR defect. On the other hand, from the ED-2 value, the shrinkage behavior in the 2nd stage is deduced to be due to the desorption of interstitial Si atoms. These findings suggest that this two-stage shrinkage behavior is peculiar to the EOR defects formed in the CH4N-ion-implanted epitaxial Si wafer, and that the interaction between the EOR defect and the impurities segregated at the edge of the defect affects the thermal robustness of the molecular-ion-implantation-induced EOR defects.

DOI： 10.1149/1945-7111/ac63f4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

Three-dimensional (3D) stacked complementary metal oxide semiconductor (CMOS) image sensors require reduction in leakage current due to interface state defects at the SiO<inf>2</inf>/Si interface. Hydrocarbon molecular ion implanted silicon wafers have identified the hydrogen termination effect of such wafer, contributing to high performance of CMOS image sensors. However, recently, low-temperature heat treatment during a device process has been shown to reduce the concentration of hydrogen diffusing from the hydrocarbon-molecular-ion-implanted region. Thus, a new method of molecular ion implantation with phosphorus added has been developed. In this paper, we present the results of our analysis of the diffusion behavior of hydrogen in a hydrocarbon molecule with phosphorus (CH<inf>2</inf>P) by reaction kinetic analysis and TCAD simulation. The results of reaction kinetic analysis show binding energies of 0.76 eV (C–H<inf>2</inf> binding state) and 0.45 eV (P–H binding state). TCAD simulation results show that the 0.76 eV binding energy indicates that hydrogen is adsorbed in a carbon and silicon self-interstitial cluster (C/I cluster). On the other hand, the binding energy of 0.45 eV indicates that hydrogen is trapped in phosphorus complexes. Hydrogen in the CH<inf>2</inf>P-implanted region diffuses owing to the difference in between these binding states. Thus, a reduction in the interface state density of Si/SiO<inf>2</inf> can be expected.

DOI： 10.1016/j.mssp.2021.106211

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Japan Society of Vacuum and Surface Science  

<p>We investigated the annealing behavior of hydrogen in a high-dose hydrocarbon-molecular-ion-implanted silicon during rapid thermal annealing (RTA). Gettering sinks in the high-dose hydrocarbon-molecular-ion-implanted region are formed not only at carbon-related defects but also at defects related to the amorphous layer after RTA. The concentration of hydrogen trapped by the defects was analyzed by secondary ion mass spectrometry (SIMS). As a result, the concentration of hydrogen trapped by the amorphous-related defects was found to be higher than that of hydrogen trapped by carbon-related defects with increasing temperature. The dissociation activation energy of trapped hydrogen at each type of defect was estimated using the consecutive reaction model. The dissociation energies at amorphous-related and carbon-related defects are 0.94 ± 0.22 and 0.67 ± 0.12 eV, respectively. The hydrogen trapped in the amorphous-related defects is considered to be in a bonding state with multivacancies, such as H₂–V₆. On the other hand, its bonding state in the carbon-related defects is assumed to be C–H₂ in carbon and self-interstitial silicon (C_s–I) clusters and H₂–V in tetrahedral (<i>T</i>_d) sites. Therefore, a high gettering capability of hydrogen can be expected by forming the amorphous-related defects peculiar to the high-dose implantation conditions.</p>

DOI： 10.1380/EJSSNT.2022-029

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：6th IEEE Electron Devices Technology and Manufacturing Conference Edtm 2022  

Using a new multielement-molecular-ion implantation technique with carbon, hydrogen, and phosphorus, we developed an epitaxial silicon wafer with proximity gettering sinks under the epitaxial growth layer. This novel silicon wafer has a high gettering capability for metallic impurity contamination. A CMOS image sensor fabricated with this wafer shows a drastic reduction of white spot defects, as revealed by dark-current spectroscopy. Therefore, CH2P-molecular-ion-implanted epitaxial silicon wafers contribute to the improvement of high-performance CMOS image sensor characteristics. (Keywords: Molecular ion, CMOS image sensor, White spot defects)

DOI： 10.1109/EDTM53872.2022.9798279

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE International Symposium on Semiconductor Manufacturing Conference Proceedings  

In this study, the diffusion behavior of hydrogen in a CH4N-molecular-ion-implanted epitaxial wafer was investegated by reaction kinetic analysis. Two hydrogen-trapping sites, carbon aggregate and end of range (EOR) defects, were formed in the CH4N-implanted region. The C-H2 binding state was formed in the carbon aggregate region. On the other hand, the N-H binding state was formed in the EOR defect region. This result indicates that CH4N-molecular-ion-implanted epitaxial wafers contribute to the reduction in Dit at the SiO2/Si interface due to hydrogen desorption from the CH4N-implanted region during heat treatment in the device process.

DOI： 10.1109/ISSM55802.2022.10027110

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

We developed a novel hybrid-molecular-ion-implantation technique for proximity gettering to reduce the carbon dose. In this molecular-ion-implantation technique, a molecular ion beam with a mixture of silicon hydride and hydrocarbon-molecular-ions is used. We found that 150 nm silicon {111} extrinsic Frank-type dislocation loops in the ion-implanted region are formed by this technique after epitaxial growth. Nickel and copper gettering test results showed that the ion-implanted region can getter Ni and Cu contaminants that diffused from the wafer surface at a carbon dose lower than those in hydrocarbon-molecular-ion-implanted wafers. We determined by energy dispersive x-ray (EDX) observation that end of range defects (EOR) act as gettering sites. We speculate two types of gettering induced by this technique: the relaxation-type gettering caused by EOR defects and the segregation-type gettering caused by the high concentration of carbon around EOR defects.

DOI： 10.1016/j.mssp.2021.106063

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2021 7th International Workshop on Low Temperature Bonding for 3D Integration Ltb 3D 2021  

We proposed the fabrication of the laminated wafer with the conductive diamond layer as an alternative SOI wafer for micro-electro mechanical systems (MEMS) sensors by chemical vapor deposition (CVD) and surface-activated bonding (SAB), in order to prevent the charge-up of devices on a BOX layer during plasma treatments. We demonstrated that the use of this laminated wafer could be deposited the boron-doped diamond layer and be bonded a silicon wafer (layer) at room temperature without a thermal stress. Therefore, we believe that this laminated wafer can contribute to the improvement of MEMS sensors as an alternative SOI wafer.

DOI： 10.1109/LTB-3D53950.2021.9598418

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We propose a fabrication process for a silicon on insulator (SOI) wafer with an extremely thick buried oxide (BOX) layer for custom micro-electro mechanical systems (MEMS) devices. A BOX layer is generally formed by thermal oxidation above 800 °C. It is limited for this method to form an extremely thick layer of more than 10 μm. Thus, we attempted to deposit the BOX layer by chemical vapor deposition at 300 °C for a short time, followed by annealing at above 300 °C to make it denser. In addition, a silicon layer was bonded to the BOX layer at room temperature by surface activated bonding not to receive thermal stress. As a result, the bonding interface had no voids. The breakdown electric field of the BOX layer in the accidental B mode was improved by annealing. Therefore, SOI wafers fabricated by our method will be beneficial to next-generation MEMS device fabrication.

DOI： 10.35848/1347-4065/abe2b9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：{IOP} Publishing  

The reduction in the density of SiO2/Si interface state (D it) in the isolation region and transfer transistor gate oxide is necessary to improve the performance of complementary metal-oxide semiconductor (CMOS) image sensors. In this study, we demonstrated that a hydrocarbon-molecular-ion-implanted epitaxial silicon wafer can reduce the D it and Pb0 center density in SiO2/Si interface regions analyzed by quasi-static capacitance-voltage and electron spin resonance measurements, respectively. The D it and Pb0 center density of wafers without hydrocarbon molecular ions increased after annealing at 700 °C. On the other hand, the D it and Pb0 center density of wafers implanted with hydrocarbon molecular ions decreased after annealing at 700 °C. We also estimated the activation energy to be 1.67 eV for the hydrogen termination reactions with hydrogen molecules and Si dangling bonds at the SiO2/Si interface. The termination effects of the hydrocarbon-molecular-ion-implanted epitaxial silicon wafers can contribute to the high electrical performance of CMOS image sensors.

DOI： 10.35848/1347-4065/abc3d8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Sensors Switzerland  

The impact of hydrocarbon-molecular (C<inf>3</inf> H<inf>6</inf>)-ion implantation in an epitaxial layer, which has low oxygen concentration, on the dark characteristics of complementary metal-oxide-semiconductor (CMOS) image sensor pixels was investigated by dark current spectroscopy. It was demonstrated that white spot defects of CMOS image sensor pixels when using a double epitaxial silicon wafer with C<inf>3</inf> H<inf>6</inf>-ion implanted in the first epitaxial layer were 40% lower than that when using an epitaxial silicon wafer with C<inf>3</inf> H<inf>6</inf>-ion implanted in the Czochralski-grown silicon substrate. This considerable reduction in white spot defects on the C<inf>3</inf> H<inf>6</inf>-ion-implanted double epitaxial silicon wafer may be due to the high gettering capability for metallic contamination during the device fabrication process and the suppression effects of oxygen diffusion into the device active layer. In addition, the defects with low internal oxygen concentration were observed in the C<inf>3</inf> H<inf>6</inf>-ion-implanted region of the double epitaxial silicon wafer after the device fabrication process. We found that the formation of defects with low internal oxygen concentration is a phenomenon specific to the C<inf>3</inf> H<inf>6</inf>-ion-implanted double epitaxial wafer. This finding suggests that the oxygen concentration in the defects being low is a factor in the high gettering capability for metallic impurities, and those defects are considered to directly contribute to the reduction in white spot defects in CMOS image sensor pixels.

DOI： 10.3390/s20226620

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms  

The gettering behavior in a hydrocarbon molecular (C<inf>3</inf>H<inf>5</inf>) ion implanted region was investigated using atom probe tomography (APT) with the aim of improving electrical properties of CMOS image sensors (CISs) and stacked CISs. APT clarified the formation of carbon atom agglomerates with copper and oxygen gettering capability in the C<inf>3</inf>H<inf>5</inf> ion implanted region. However, there were no oxygen atoms near the copper atoms in the C<inf>3</inf>H<inf>5</inf> ion implanted region. In addition, the copper gettering capability of each carbon atom agglomerates decreased with increasing ratio of the number of oxygen atoms to that of carbon atoms in the carbon atom agglomerates. The copper and oxygen gettering mechanism was considered to involve the formation of a complex with carbon-containing gettering sites. Oxygen degrades the copper gettering capability of carbon atom agglomerates by the formation of stable complexes with carbon-containing gettering sites, which can also act as copper gettering sites. Consequently, the oxygen concentration in the C<inf>3</inf>H<inf>5</inf> ion implanted regions is an important factor in improving the electrical properties of CISs and stacked CISs.

DOI： 10.1016/j.nimb.2020.05.017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We propose a process for the fabrication of a silicon-on-insulator (SOI) wafer with a silicon carbide (SiC) insulator layer by combining plasma-enhanced chemical vapor deposition and surface-activated bonding without thermal stress to obtain sufficient thermal conductivity for self-heating power and high-frequency device applications. The thermal conductivity of the deposited SiC layer is twice that of a silicon dioxide (SiO<inf>2</inf>) layer, and the breakdown electric field of this layer is 10-11 MV cm^-1, the same as that of a SiO<inf>2</inf> layer. In addition, the bonding interface between the silicon layer and the deposited SiC insulator layer has no voids or punch-out dislocations. Therefore, the SOI wafer with a SiC layer has high thermal conductivity and breakdown electric field; this SOI wafer and its fabrication process will be important for the realization of next-generation self-heating devices such as power and high-frequency devices.

DOI： 10.35848/1347-4065/ab82af

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The fabrication cost of bonded silicon on insulator (SOI) wafers for customized power devices is high owing to the high temperature required and the very long fabrication process involving both thermal oxidation and bonding. In addition, SOI wafers are contaminated with metallic impurities during the formation of the buried oxide (BOX) layer and the bonding of a silicon layer on the BOX layer. Therefore, we propose an alternative SOI wafer fabrication method combining BOX layer deposition and surface activated bonding at room temperature in a vacuum without any voids. There is also no fixed charge in the deposited BOX layer, and the breakdown voltage of this layer is 11-12 MV cm^-1, the same as that for a thermal oxide layer.

DOI： 10.7567/1347-4065/ab516e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of the Electrochemical Society  

Using proton (H+)-implanted silicon (Si) substrates, we clarified the effect of dangling bond termination by hydrogen on the interfacial strain in the silicon dioxide (SiO2)/Si system. The variations of the SiO2/Si interface structure caused by H+ implantation into a SiO2/Si sample and by hydrogen out-diffusion heat treatment were analyzed by high-resolution synchrotron radiation photoemission spectroscopy. We found that H+ implantation into the SiO2/Si sample [intentional generation of the interfacial dangling bonds] can increase the intensity of the strained-Si peaks in the Si 2p photoemission spectrum. In addition, our study revealed that the strained Si atom amount and dangling bond density are reduced by hydrogen out-diffusion heat treatment. These findings suggest that the increase/decrease in the dangling bond density by H atoms results in the increase/decrease in local strain field around a dangling bond, thereby changing the length of the Si-Si bonds beneath the SiO2/Si interface. Out-diffused hydrogen seems to play roles to not only reduce the dangling bond density but also relax the local strain at the SiO2/Si interface. The hydrogen termination effect is expected to have an advantage in structural stability in the SiO2/Si system as compared with the pure thermal termination effect.

DOI： 10.1149/1945-7111/abac85

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We investigate the amorphous formation behavior on hydrocarbon molecular ion implantation conditions such as hydrocarbon molecular ion size by X-ray photoelectron spectroscopy (XPS). The cross-sectional radius of the amorphous region was obtained from the peak intensity of the amorphous component in Si 2p spectra analyzed by XPS, and using columnar formula for a model. We confirmed that the cross-sectional radius of the amorphous region formed by hydrocarbon molecular ions differs greatly from that formed by monomer carbon ions, and increases by 0.078 nm as the number of carbon atoms composing the hydrocarbon molecular ion increases. The dependence of amorphous formation on the hydrocarbon molecular size is related to the C-C binding distance, and the ratio of increase in the amorphous cross-sectional radius corresponds to half of the C-C binding distance. Therefore, the collision behavior of hydrocarbon molecular ions during implantation predominantly influence the size of hydrocarbon molecular ions.

DOI： 10.35848/1347-4065/ab6ed5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：{IOP} Publishing  

We propose to use a bonding wafer as an alternative epitaxial wafer with an extra thick epitaxial layer of more than 100 μm thickness to fabricate vertical time-of-flight (TOF) complementary metal-oxide-semiconductor (CMOS) imaging sensors that can detect infrared (IR) radiation of wavelength greater than 1120 nm. This bonding wafer comprises a floating zone (FZ)-grown silicon wafer bonded to a Czochralski (CZ)-grown silicon substrate by room-temperature surface-activated bonding. Because the device-fabricating region is formed by bonding the FZ-grown wafer to the CZ-grown silicon substrate at room temperature, the oxygen concentration in this region is decreased to less than that in an epitaxial wafer. In addition, our bonded wafer can have a strong gettering capability for oxygen and transition metals (nickel, copper, and iron) in the bonding interface. Furthermore, the bonded wafer can inhibit out-diffusion of oxygen or transition metal to the device-fabricating region from the CZ-grown silicon substrate, and the device-fabricating region can have fewer impurities after fabricating the devices in the bonded wafer. Therefore, we consider that this bonded wafer can be fabricated by the simple processes of bonding and grinding (polishing) at room temperature without thermal stress, and this method is effective for decreasing the dark currents and white-spot defects generated owing to the presence of oxygen or transition metal, which are undesirable in advanced TOF-CMOS imaging sensors of a vertical structure.

DOI： 10.35848/1347-4065/abcdb4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physica Status Solidi A Applications and Materials Science  

Fundamental characteristics such as metal-gettering capability and defect morphology of a cyanide-related multielement molecular (CH<inf>4</inf>N) ion-implanted epitaxial silicon (Si) wafer are investigated. It is found that the CH<inf>4</inf>N ion-implanted epitaxial Si wafer has a higher gettering capability for transition metallic impurities than a hydrocarbon molecular (C<inf>3</inf>H<inf>5</inf>) ion-implanted epitaxial Si wafer. This higher metal-gettering capability of the CH<inf>4</inf>N ion-implanted epitaxial Si wafer may be due to the formation of stacking faults as well as carbon (C) agglomeration defects in the CH<inf>4</inf>N ion-implanted region during the epitaxial Si layer growth process. The formation of stacking faults may be a specific phenomenon in the case of the CH<inf>4</inf>N ion implantation. In addition, the CH<inf>4</inf>N ion-implanted region can trap high concentrations of hydrogen (H) and nitrogen (N) atoms during the epitaxial Si growth. This fact suggests that the distribution of N atoms is strongly associated with the defect morphology and C distribution in the CH<inf>4</inf>N ion-implanted region. The CH<inf>4</inf>N ion-implanted epitaxial Si wafer with these characteristics has the potential to improve the performance of complementary metal-oxide-semiconductor (CMOS) image sensors.

DOI： 10.1002/pssa.201900172

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physica Status Solidi A Applications and Materials Science  

In this study, two types of hydrogen diffusion behavior in the projection range of a hydrocarbon molecular ion after high-temperature heat treatment for the passivation of interface state defects at SiO<inf>2</inf>/Si interface of the CMOS image sensor is presented. The hydrogen peak concentration in the hydrocarbon ion projection range is observed by secondary ion mass spectrometry analysis after silicon epitaxial growth and the subsequent high-temperature heat treatment. Moreover, the hydrogen peak concentration strongly depends on heat treatment time after epitaxial growth and the subsequent heat treatment. Two dissociation activation energies by reaction kinetic analysis using the results of the time dependence of hydrogen diffusion behavior are also determined. Assuming two dissociation reactions, the activation energy from the projection range of a hydrocarbon molecular ion is derived. The results of reaction kinetic analysis show that the dissociation activation energies are 0.79 eV for molecular hydrogen and 0.42 eV for atomic hydrogen. The dissociation activation energy of 0.79 eV indicates molecular hydrogen diffusion activation energy, whereas that of 0.42 eV indicates atomic hydrogen diffusion from the projection range of a hydrocarbon molecular ion. Therefore, it is believed that the molecular and atomic hydrogen diffusion behavior of the hydrocarbon molecular ion implanted silicon epitaxial wafers can contribute to the effective reduction in the density of interface state defects at the SiO<inf>2</inf>/Si interface.

DOI： 10.1002/pssa.201900175

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1380/vss.62.306

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI} {AG  

We developed silicon epitaxial wafers with high gettering capability by using hydrocarbon-molecular-ion implantation. These wafers also have the effect of hydrogen passivation on process-induced defects and a barrier to out-diffusion of oxygen of the Czochralski silicon (CZ) substrate bulk during Complementary metal-oxide-semiconductor (CMOS) device fabrication processes. We evaluated the electrical device performance of CMOS image sensor fabricated on this type of wafer by using dark current spectroscopy. We found fewer white spot defects compared with those of intrinsic gettering (IG) silicon wafers. We believe that these hydrocarbon-molecular-ion-implanted silicon epitaxial wafers will improve the device performance of CMOS image sensors.

DOI： 10.3390/s19092073

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Proceedings of 2019 6th International Workshop on Low Temperature Bonding for 3D Integration Ltb 3D 2019  

We proposed the fabrication of an SOI wafer for customized power devices by chemical vapor deposition (CVD) of a BOX layer and surface-activated bonding (SAB). We demonstrated that the use of this SOI wafer can form an extra thick BOX layer of 10 ^{\circ }\mu \mathrm {m} and can be fabricated at temperature below 500 °C without thermal stress. Therefore, we believe that this SOI wafer can contribute to the improvement of customized power devices with breakdown voltages of over 500V.

DOI： 10.23919/LTB-3D.2019.8735178

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We propose a fabrication process for a silicon on insulator (SOI) wafer with a diamond buried oxide (BOX) layer by combining nanodiamond-seeding deposition and a surface-activated bonding technique for high-frequency and power device applications. The diamond layer was deposited on a base wafer by the spin-coating of nanodiamonds and microwave-plasma-enhanced chemical vapor deposition. The thermal conductivity of this deposited diamond layer was three times that of a conventional SiO <inf>2</inf> layer. A silicon wafer was then bonded to the diamond layer at room temperature in ultrahigh vacuum without forming any voids. Additionally, this SOI wafer was used to fabricate devices at 1000 °C. Therefore, we believe that this SOI wafer with a diamond BOX layer and its fabrication process are important for the realization of self-heating devices such as next-generation high-frequency and power devices.

DOI： 10.7567/1347-4065/aaea6d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Sensors and Materials  

We developed a high-gettering-capability silicon wafer for advanced CMOS image sensors using hydrocarbon molecular ion implantation. We found that this novel silicon wafer has an extremely high gettering capability for metal, oxygen, and hydrogen impurities during the CMOS device fabrication process. We also found that the white spot defect density of a hydrocarbon-molecular-ion-implanted CMOS image sensor was substantially lower than that of a CMOS image sensor without hydrocarbon molecular ion implantation. This indicates that the novel silicon wafer helped improve device performance parameters such as white spot defect density and dark current. We believe that this wafer will be beneficial in the design of silicon wafers for advanced CMOS image sensor fabrication.

DOI： 10.18494/SAM.2019.2313

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

In our published paper, the STEM image in Fig. 12(b) is incorrectly the same as Fig. 12(a). The correct appearance of Fig. 12(b) is shown here. The discussions and conclusions are not altered by this correction. (Figure presented).

DOI： 10.7567/1347-4065/ab3e59

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We have characterized CH<inf>3</inf>O ion-implanted epitaxial wafers in device fabrication processes. We confirmed that the CH<inf>3</inf>O ion-implanted wafers can reduce the density of white spot defects in CMOS image sensors. Evaluation of the CH<inf>3</inf>O ion-implanted region before and after device fabrication processes which included heat treatment and ion implantation, showed that two types of defects, namely stacking faults and carbon-related defects, exist in the CH<inf>3</inf>O ion implantation region getter the metallic impurities during device fabrication processes. In particular, it was clarified that stacking fault defects existing in the CH<inf>3</inf>O ion-implanted region are powerful gettering sinks for oxygen. Thus, it was considered that two types of gettering sink formed by CH<inf>3</inf>O ion implantation contribute to the reduction in the density of white spot defects. We believe that these characteristics can contribute to the improvement of fabrication processes for advanced CMOS image sensors.

DOI： 10.7567/1347-4065/ab358b

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The dependence of the density of CH<inf>3</inf>O ion-implantation defects on ramping up rate after annealing at 1100 C for 300 s have been investigated using rapid thermal annealing. We found that the density of defects after annealing was highest at a ramping up rate of 15 C s^-1. Furthermore, we also found that the diffusion behavior of implanted carbon and oxygen which were gettered by the CH<inf>3</inf>O ion-implantation defects, was dependent on the annealing temperature. Therefore, the ramping up rate dependence of the density of CH<inf>3</inf>O ion-implantation defects was considered to be caused by the difference between the formation behavior of CH<inf>3</inf>O ion-implantation defects and the dissociative adsorption behavior of carbon and oxygen. An increase in the defect density led to an increase in the density of gettering sinks. The gettering capability of the CH<inf>3</inf>O ion-implantation region is expected to be improved by optimizing the ramping up rate.

DOI： 10.7567/1347-4065/ab4fc9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The interaction of iron (Fe) with defects induced by a high hydrocarbon-molecular-ion-implantation dose of 1 ' 10¹⁶ cm^%2 in a Czochralski-grown silicon substrate and an epitaxial growth layer was investigated using secondary ion mass spectroscopy, transmission electron microscopy, and laser-assisted atom probe tomography (L-APT). High-dose hydrocarbon-molecular-ion-implantation formed two types of defects in the projection range: stacking faults and carbon agglomerates. It was demonstrated that the dominant gettering mechanisms of the two types of defects differ. Carbon agglomerates formed by implantation of the epitaxial growth layer exhibited high gettering efficiency for Fe. The L-APT data indicated that the Fe gettering efficiency is strongly affected by the distribution of oxygen atoms in carbon agglomerates. It is suggested that Fe gettering on agglomerates is due to the strong electronic interaction between carbon agglomerates and Fe but suppressed by oxygen atoms in agglomerates.

DOI： 10.7567/JJAP.57.091302

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Proceedings of the International Conference on Ion Implantation Technology  

We have developed hydrocarbon molecular ion implanted epitaxial wafers for advanced CMOS image sensors. The hydrocarbon molecular ion implanted region has the highest gettering capability for metallic impurities and plays a barrier role for-diffused oxygen atoms from CZ grown Si substrate. In addition, implanted hydrogen atoms diffuse out and passivate process-induced defects in device process. It is previously reported that high-dose hydrocarbon molecular ion implantation enhances these characteristics even more. However in high-dose implantation condition, stacking faults are formed in epitaxial layer. In this study, the flash lamp annealing is investigated as recovery annealing after high-dose implantation. The flash lamp annealing is expected to change the re-crystallization behavior of amorphous layer and suppress the formation of stacking faults in epitaxial layer without diffusion of hydrogen atoms from implanted region. Consequently, by the flash lamp annealing after high-dose implantation the stacking faults in epitaxial layer are perfectly suppressed. Furthermore, high concentration hydrogen remains in implanted region after FLA and epitaxial growth process due to change of defect morphology. Without recovery annealing after high-dose implantation, amorphous layer is re-crystallized in ramp-up time of epitaxial growth process and clamshell type defects are formed. Conversely, by flash lamp annealing high density small defect are formed. These high density small defects are contributed to remain hydrogen atoms in implanted region.

DOI： 10.1109/IIT.2018.8807907

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Proceedings of the International Conference on Ion Implantation Technology  

The metallic impurity gettering capability of hydrocarbon molecular ion-implanted silicon wafers was demonstrated by using a complementary metal-oxide-semiconductor (CMOS) image sensor that provides floating diffusion amplifier voltage (V<inf>dark</inf>) output signals under dark conditions. It was found that the V<inf>dark</inf> output signals of hydrocarbon molecular ion implanted p/p- and p/p+ silicon wafers did not increase after intentional contamination with Fe, Cu, Ni and Co metallic impurities. This indicates that the hydrocarbon molecular ion implanted silicon wafers were able to getter metallic impurities in the projection range of hydrocarbon molecular ion implantation during CMOS device fabrication. It was also found that the hydrocarbon-molecular-ion-implanted silicon wafers had improved electrical device performance factors, such as pn-junction leakage current, in actual device process lines. This gettering technique has no dependence on the silicon wafer substrates such as whether it is composed of bulk por p+ boron doped silicon crystals. We believe that the hydrocarbon-molecular-ion-implanted silicon wafers will be advantages for advanced CMOS image sensor fabrication.

DOI： 10.1109/IIT.2018.8807961

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We investigated the fundamental characteristics of a CH<inf>3</inf>O-ion-implanted silicon epitaxial wafer with our previously developed multielement molecular ion implantation technique and compared this technique with a conventional implantation technique, i.e., “carbon cluster ion implantation”. We found that the CH<inf>3</inf>O ion projection range has a 10-fold higher oxygen concentration than the carbon cluster ion projection range after epitaxial growth. We also found 50 nm silicon {111} stacking faults in the CH<inf>3</inf>O ion projection range. Such defects were not observed in the carbon cluster ion projection range. From nickel gettering test results, proximity gettering of nickel contaminations by CH<inf>3</inf>O ion implantation was found to be more effective than that by C<inf>2</inf>H<inf>3</inf> ion implantation. Therefore, we speculate that the CH<inf>3</inf>O ion projection range improves the gettering capability of metallic impurity contaminants through the formation of complex point defects formed by vacancies and that oxygen implanted at a high concentration and silicon {111} stacking faults are new gettering sinks.

DOI： 10.7567/JJAP.57.096503

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The association and dissociation behavior of hydrogen in the implanted region of a CH<inf>3</inf>O cluster were investigated for high-performance CMOS image sensors. Two hydrogen peaks were observed in the CH<inf>3</inf>O-implanted region after epitaxial growth and heat treatment. The difference in the depths of the two peaks accords with the difference in the depth of carbon-cluster-related and new extended stacking fault defects. Thus, we calculated the activation energies of the association and dissociation of hydrogen, assuming a dissociation reaction for the first peak, formed at a small depth from the surface of the silicon substrate, and a simple reversible reaction for the second peak, formed at a large depth from the surface of the silicon substrate. The dissociation activation energy corresponding to the first peak was 0.75 ± 0.03 eV. This activation energy indicates that the hydrogen associated with the first peak forms a binding state with a carbon and silicon self-interstitial cluster (C/I cluster). On the other hand, the binding energy corresponding to the second peak was calculated to be 0.78 eV, which was close to the C-H<inf>2</inf> binding energy. Consequently, the CH<inf>3</inf>O-implanted region forms a binding state with hydrogen and a C/I cluster or a C-H<inf>2</inf> binding state.

DOI： 10.7567/JJAP.57.081302

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2018 IEEE Electron Devices Technology and Manufacturing Conference Edtm 2018 Proceedings  

The difference in agglomerate defects formed by carbon-cluster-ion-implanted Czochralski (CZ)-Si and epitaxial Si has been investigated using atom probe tomography. In the previous work, we reported on the strong gettering capability in implanted epitaxial Si. We found that the distribution of O and C atom concentrations on agglomerates differs between CZ-Si and epitaxial Si. This suggests that a C agglomerate, which grows without including O atoms, results in strong gettering efficiency for Fe.

DOI： 10.1109/EDTM.2018.8421426

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We propose a fabrication process for silicon wafers by combining carbon-cluster ion implantation and room-temperature bonding for advanced CMOS image sensors. These carbon-cluster ions are made of carbon and hydrogen, which can passivate process-induced defects. We demonstrated that this combination process can be used to form an epitaxial layer on a carbon-cluster ion-implanted Czochralski (CZ)-grown silicon substrate with a high dose of 1×10¹⁶ atoms/cm². This implantation condition transforms the top-surface region of the CZ-grown silicon substrate into a thin amorphous layer. Thus, an epitaxial layer cannot be grown on this implanted CZ-grown silicon substrate. However, this combination process can be used to form an epitaxial layer on the amorphous layer of this implanted CZ-grown silicon substrate surface. This bonding wafer has strong gettering capability in both the wafer-bonding region and the carbon-cluster ion-implanted projection range. Furthermore, this wafer inhibits oxygen out-diffusion to the epitaxial layer from the CZ-grown silicon substrate after device fabrication. Therefore, we believe that this bonding wafer is effective in decreasing the dark current and white-spot defect density for advanced CMOS image sensors.

DOI： 10.7567/JJAP.57.061302

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C<inf>3</inf>H<inf>5</inf>) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

DOI： 10.7567/JJAP.57.021304

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

Carbon-cluster-ion-implanted defects were investigated by high-resolution cross-sectional transmission electron microscopy toward achieving high-performance CMOS image sensors. We revealed that implantation damage formation in the silicon wafer bulk significantly differs between carbon-cluster and monomer ions after implantation. After epitaxial growth, small and large defects were observed in the implanted region of carbon clusters. The electron diffraction pattern of both small and large defects exhibits that from bulk crystalline silicon in the implanted region. On the one hand, we assumed that the silicon carbide structure was not formed in the implanted region, and small defects formed because of the complex of carbon and interstitial silicon. On the other hand, large defects were hypothesized to originate from the recrystallization of the amorphous layer formed by high-dose carbon-cluster implantation. These defects are considered to contribute to the powerful gettering capability required for high-performance CMOS image sensors.

DOI： 10.7567/JJAP.57.011301

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE Journal of the Electron Devices Society  

Gettering sinks for metallic impurities formed by carbon-cluster ion implantation in epitaxial silicon wafers have been investigated using technology computer-aided design and atom probe tomography (APT). We found that the defects formed by carbon-cluster ion implantation consist of carbon and interstitial silicon clusters (carbon-interstitial clusters). Vacancy-type clusters are not dominant gettering sinks for metallic impurities in the carbon-cluster ion implanted region. APT data indicated that the distribution of oxygen atoms in the defects differs between Czochralski-grown silicon and epitaxial silicon wafers. The high gettering efficiency observed in carbon-cluster ion implanted epitaxial silicon wafers in comparison with Czochralski-grown silicon wafers is due to the distribution of oxygen atoms in the defects. Defects not containing O atoms provide strong gettering sinks for metallic impurities. These defects are formed by only carbon-interstitial clusters. Oxygen atoms inside the defects modify the amount of carbon-interstitial cluster formation on the defects. It is suggested that the gettering efficiency for metallic impurities in carbon-cluster ion implanted epitaxial silicon wafer is determined by the amount of carbon-interstitial clusters.

DOI： 10.1109/JEDS.2018.2872976

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Ecs Transactions  

We developed high gettering capability silicon wafers for advanced CMOS image sensors using hydrocarbon molecular ion implantation and surface activated direct wafer bonding (SAB). We found that this novel wafer has three unique characteristics for the improvement of CMOS image sensor device performance. The first is metallic impurity gettering capability in the hydrocarbon ion implantation projection range during CMOS device fabrication. The second is the oxygen out-diffusion barrier effect; this wafer can control out-diffusion to the device active region from the CZ grown silicon substrate during CMOS device heat treatment. The third is the hydrogen passivation effect; hydrogen passivates to the Si/SiO<inf>2</inf> gate oxide interface state defects which out-diffuse to the device active region from the hydrocarbon ion implantation projection range during the CMOS device fabrication. Moreover, we demonstrated that this novel wafer can improve the pn-junction leakage current under the actual device fabrication.

DOI： 10.1149/08605.0077ecst

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physica Status Solidi A Applications and Materials Science  

A new technique is described for manufacturing advanced silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication processes. Carbon and hydrogen elements are localized in the projection range of the silicon wafer by implantation of ion clusters from a hydrocarbon molecular gas source. Furthermore, these wafers can getter oxygen impurities out-diffused to device active regions from a Czochralski grown silicon wafer substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as the dark current, white spot defects, pn-junction leakage current, and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly improve electrical devices performance characteristics in advanced CMOS image sensors.

DOI： 10.1002/pssa.201700216

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：2017 IEEE Electron Devices Technology and Manufacturing Conference Edtm 2017 Proceedings  

We describe the effect of microwave heating on C<inf>3</inf>H<inf>5</inf> carbon cluster ion implanted epitaxial wafers using a high dose amount of carbon cluster ion implantation condition. A high dose amount condition of C<inf>3</inf>H<inf>5</inf> carbon cluster ion implantation generates implantation-related defects, such as stacking faults, after epitaxial growth. Therefore, we investigated the control and reduction of stacking faults using the microwave heating technique. We revealed that this technique can control and reduce stacking faults by selectively heating of the carbon cluster ion implantation projection range.

DOI： 10.1109/EDTM.2017.7947506

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

In Figs. 9(a) and 10(a), the unit of the horizontal axis should be nm instead of um. The corrected figures are shown below. The correct figures were used during the review process.

DOI： 10.7567/JJAP.56.049201

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

We investigated the diffusion behavior of hydrogen in a silicon wafer made by a carbon-cluster ion-implantation technique after heat treatment and silicon epitaxial growth. A hydrogen peak was observed after high-temperature heat treatment (>1000°C) and silicon epitaxial growth by secondary ion mass spectrometry analysis. We also confirmed that the hydrogen peak concentration decreased after epitaxial growth upon additional heat treatment. Such a hydrogen diffusion behavior has not been reported. Thus, we derived the activation energy from the projected range of a carbon cluster, assuming only a dissociation reaction, and obtained an activation energy of 0.76 ± 0.04 eV. This value is extremely close to that for the diffusion of hydrogen molecules located at the tetrahedral interstitial site and hydrogen molecules dissociated from multivacancies. Therefore, we assume that the hydrogen in the carbon-cluster projected range diffuses in the molecular state, and hydrogen remaining in the projected range forms complexes of carbon, oxygen, and vacancies.

DOI： 10.7567/JJAP.56.025601

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Japanese Journal of Applied Physics  

A new technique is described for manufacturing silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication. It is demonstrated that this technique can implant wafers simultaneously with carbon and hydrogen elements that form the projection range by using hydrocarbon compounds. Furthermore, these wafers can getter oxygen impurities outdiffused from the silicon substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as dark current and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly reduce dark current in advanced CMOS image sensors.

DOI： 10.7567/JJAP.55.121301

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics  

The iron-related deep levels in n-type silicon and their thermal stabilities were investigated by deep-level transient spectroscopy (DLTS). Three deep energy levels at E<inf>c</inf> % 0.35, E<inf>c</inf> % 0.41, and E<inf>c</inf> % 0.48 eV were observed and classified into two types from the annealing behavior at room temperature and a low temperature of 200 °C. We found for the first time that only one iron-related deep level at Ec % 0.35 eV was highly stable at room temperature and 200 °C, while other iron-related deep levels were unstable. We also found that the concentration of the deep energy level at E<inf>c</inf> % 0.41 eV gradually decreased at room temperature. These results suggest that the origin of the thermally stable level at E<inf>c</inf> % 0.35 eV is attributed to the substitutional iron-related level, and those of the thermally unstable levels at E<inf>c</inf> % 0.41 and E<inf>c</inf> % 0.48 eV are attributed to interstitial iron-related complexes such as iron-acceptor pairs in p-type silicon.

DOI： 10.7567/JJAP.55.021301

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DOI： 10.1143/JJAP.47.5619

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Science and Engineering B  

We investigated the gettering efficiency of iron and nickel in Czochralski (CZ) silicon wafers depending on crystalline nature such as interstitial-silicon-dominant or vacancy-dominant crystal growth. After a typical heat treatment for dynamic random access memories (DRAMs), the density of silicon oxide precipitates in the vacancy-dominant crystal regions was approximately two orders higher than interstitial-silicon-dominant crystal regions. After a DRAM heat treatment, irons were preferably gathered at vacancy-dominant crystal region while nickels were selectively at only an interstitial-silicon-dominant crystal region. Silicon wafers designed with extreme gettering ability via rapid thermal annealing (RTA) at 1150 °C for 10 s using NH<inf>3</inf> and Ar gas mixture produced the "M" shape of oxygen precipitates in which the peak density of the precipitates was in the range of ∼3 × 10¹⁰ cm^-3 while the bulk density was in the range of ∼2 × 10⁹ cm^-3. The RTA silicon wafer completely eliminated irons and nickels from the wafer surface that are gathered at oxygen precipitates in silicon bulk during a DRAM heat treatment. © 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.mseb.2006.07.034

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DOI： 10.1149/1.2159296

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DOI： 10.1149/1.1928229

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Microelectronic Engineering  

The gettering efficiency of both iron and nickel in a Czochralski silicon wafer strongly depends on the crystal nature, i.e. an interstitial silicon dominant crystal or a vacancy dominant crystal. After heat treatment of dynamic random access memory, iron is mainly precipitated in the vacancy dominant crystal region rather than the interstitial silicon dominant crystal region, since the density of silicon oxide precipitate in the vacancy dominant crystal region is approximately two orders higher than that in the interstitial silicon dominant crystal region. This indicates that the mechanism of iron gettering is associated with relaxation gettering by silicon oxide precipitates. Otherwise, nickel silicides at the wafer surface are dominantly produced in the interstitial silicon crystal region, while nickel is chiefly precipitated at silicon oxide precipitates in the vacancy dominant crystal region. Also, this result demonstrates that the mechanism of nickel gettering is associated with relaxation gettering by silicon oxide precipitates, since silicon oxide precipitates are virtually not produced in the interstitial silicon dominant crystal region. A super silicon wafer designed for proximity gettering by silicon oxide precipitates shows a superior gettering efficiency for iron and nickel via the elimination of the memorized crystal nature. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0167-9317(02)00916-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics Part 1 Regular Papers and Short Notes and Review Papers  

Deep level transient spectroscopy analysis of copper-doped p-type floating-zone silicon (FZ-Si) wafer was performed. Five deep energy level states observed in copper-doped silicon (E<inf>v</inf> + 0.1 eV, E<inf>v</inf> + 0.15 eV, E<inf>v</inf> + 0.22 eV, E<inf>v</inf> + 0.26 eV and E<inf>v</inf> + 0.43 eV) with concentrations of 1 × 10¹¹ to 1 × 10¹² cm^-3 were detected. We observed that the amplitude of only one peak (deep level at E<inf>v</inf> + 0.26 eV) dramatically decreased with time during storage at room temperature, but stabilized at a concentration of about 1 × 10¹² cm^-3 after 2 days. The other deep level concentrations did not change after two months storage at room temperature. Therefore, it was concluded that room-temperature annealing resulted in a decrease in the deep level at E<inf>v</inf> + 0.26 eV due to the formation of copper-precipitate related defects and out-diffusion to the silicon surface.

DOI： 10.1143/jjap.40.1167

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics Part 1 Regular Papers and Short Notes and Review Papers  

DOI： 10.1143/jjap.41.446

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics Part 1 Regular Papers and Short Notes and Review Papers  

We investigated the electronic passivation of a silicon surface by iodine termination. The surface recombination velocity on iodine-terminated Si(100) was less than 10 cm/s, which is better than that obtained from oxide-passivated silicon surfaces. X-ray photoelectron spectroscopy (XPS) showed that the iodine-terminated silicon surface appeared to be covered by covalent silicon iodine bonds. This surface has no surface dangling bonds to act as recombination centers. We describe a simple model for this surface coverage phenomena of Si-X where X is a monovalently bonded iodine atom. We demonstrate the use of iodine-ethanol solution as an alternative to oxidation for controlling silicon surface chemistry.

DOI： 10.1143/jjap.38.5710

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Journal of Applied Physics Part 1 Regular Papers and Short Notes and Review Papers  

The identification of metallic impurities in p-type silicon has been studied using a microwave photoconductive decay lifetime measurement method at various high injection levels. The light illumination time and carrier injection level dependences of the recombination lifetime show unique characteristics for recombination centers attributed to Fe- and Cr-related levels. The clear identification of iron and chromium is achieved by analyzing the carrier injection level dependence curve and the light illumination time measured before and after the light illumination treatment.

DOI： 10.1143/jjap.37.5861

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASTM Special Technical Publication  

The prospect of identifying metallic impurities in p-type silicon has been studied by using the microwave photoconductive decay lifetime measurement method at various high injection levels. Samples intentionally doped with transition metals during crystal growth were prepared. It was found that point defects associated with Fe-B, Cr-B, and Ti, in decreasing order of effectiveness, degrade recombination lifetime in p-type Si. The effects of Fe-B pairs and Fe-B pair dissociation on recombination lifetime were also compared by various high injection levels.

DOI： 10.1520/stp15694s

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Applied Physics  

We have studied the initial stages of oxidation of the hydrogen-terminated Si(111) and (100) surfaces stored in air, using infrared spectroscopy in the multiple internal reflection geometry. We investigate the effect of surface roughness and humidity of air on the oxidation of the hydrogen-terminated Si surfaces. We suggest that surface roughness on a microscopic scale does not significantly affect the oxidation of the hydrogen-terminated Si surface and the oxidation occurs on the entire surface. It is demonstrated that water is predominantly involved in the oxidation of the surface Si - H bond, and that the surface Si - H bond is quite inert to the oxygen molecule.

DOI： 10.1063/1.357627

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Applied Physics Letters  

The chemical nature of Si surfaces treated with ammonium fluoride (NH <inf>4</inf>F) has been investigated using photoemission and surface infrared spectroscopy. On the surface after treatment in NH<inf>4</inf>F solution, there remain ammonium compounds such as NH<inf>4</inf>F and NH<inf>4</inf>F.HF. Photoemission data demonstrate that under the atmospheric environment, the ammonium compounds remaining on the NH<inf>4</inf>F-treated Si surface react with the Si substrate to generate the hexafluorosilicate salt, (NH <inf>4</inf>)<inf>2</inf>SiF<inf>6</inf>. We propose that the formation of (NH<inf>4</inf>)<inf>2</inf>SiF<inf>6</inf> or SiF<inf>6</inf>^2- ions is the dominant reaction pathway in the NH<inf>4</inf>F etching of Si crystals.

DOI： 10.1063/1.108562

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Applied Physics  

Morphologies of Si surfaces treated with aqueous solutions of hydrofluoric acid (HF) and ammonium fluoride (NH<inf>4</inf>F) have been investigated using surface infrared spectroscopy. We confirm that HF-treated Si(111) surfaces are terminated with a monohydride (Si - H), dihydride (Si - H<inf>2</inf>), and trihydride (Si-H<inf>3</inf>), whereas NH<inf>4</inf>F-treated Si(111) surfaces are dominantly terminated with Si - H. For Si(100), treatment in NH<inf>4</inf>F produces a surface for which the dihydride mode is enhanced compared to HF treatment, suggesting that surface Si - Si bonds on Si(100) are readily cleaved in a NH<inf>4</inf>F solution to generate a dihydride Si. The effect of varying the HF concentration on the morphology of HF-treated Si(100) surfaces is investigated. It is demonstrated that 5% HF treatment produces Si(100) surfaces which have a larger density of surface Si - Si bonds than 50% HF or 0.5% HF treatment.

DOI： 10.1063/1.350497

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Applied Physics  

The Si(111) surface treated in a saturated solution of NH<inf>4</inf>F has been investigated using photoemission spectroscopy with synchrotron radiation and surface infrared spectroscopy (SIS) in the multiple internal reflection mode. Photoemission and SIS data clearly demonstrate that the NH <inf>4</inf>F-treated Si(111) surface is dominantly terminated with the monohydride Si (Si-H) oriented perpendicular to the surface and is free from silicon oxide. It is suggested that the absence of silicon oxide is closely related to the atomic flatness of this surface.

DOI： 10.1063/1.351541

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：IEEE Journal of the Electron Devices Society  

We have developed silicon epitaxial wafers with high gettering capability using hydrocarbon molecular ion implantation for advanced Complementary Metal-Oxide-Semiconductor (CMOS) image sensors. These wafers have three unique silicon wafer characteristics for improvement of CMOS device electrical parameter such as high metallic impurity gettering, oxygen out-diffusion barrier effects from Czochralski silicon (CZ) substrate and hydrogen passivation effect for interface state defect at Si/SiO2. We demonstrate that double epitaxial growth silicon wafers have an extremely high gettering capability during CMOS device fabrication process. We also found that gettering capability strongly dependence on oxygen impurity amount in hydrocarbon molecular ion implantation projection range. We believe that this novel silicon wafer can drastically contribute to the improvement of CMOS image sensor device performance such as white spot defect and dark current.

DOI： 10.1109/JEDS.2021.3135656

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DOI： 10.11470/jsapmeeting.2021.1.0_2356

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DOI： 10.11470/jsapmeeting.2020.1.0_2588

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2019.2.0_3676

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DOI： 10.11470/jsapmeeting.2019.1.0_3323

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DOI： 10.11470/jsapmeeting.2019.1.0_3322

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DOI： 10.11470/jsapmeeting.2019.1.0_1274

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DOI： 10.11470/jsapmeeting.2018.2.0_3460

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DOI： 10.11470/jsapmeeting.2018.2.0_1362

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DOI： 10.11470/jsapmeeting.2018.1.0_3741

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DOI： 10.11470/jsapmeeting.2018.1.0_1462

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DOI： 10.11470/jsapmeeting.2018.1.0_3743

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DOI： 10.11470/jsapmeeting.2018.1.0_3742

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DOI： 10.11470/jsapmeeting.2018.1.0_3740

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DOI： 10.11470/jsapmeeting.2018.1.0_3739

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DOI： 10.11470/jsapmeeting.2017.2.0_180

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DOI： 10.11470/jsapmeeting.2017.2.0_3527

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DOI： 10.11470/jsapmeeting.2017.2.0_3526

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DOI： 10.11470/jsapmeeting.2017.2.0_3524

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DOI： 10.11470/jsapmeeting.2017.1.0_3610

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DOI： 10.11470/jsapmeeting.2017.1.0_3611

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DOI： 10.11470/jsapmeeting.2017.1.0_3613

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Japan Society of Vacuum and Surface Science  

技術賞受賞講演を行います。

DOI： 10.14886/sssj2008.37.0_53

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DOI： 10.11470/jsapmeeting.2016.2.0_3321

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DOI： 10.11470/jsapmeeting.2016.1.0_3622

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DOI： 10.11470/jsapmeeting.2016.1.0_3621

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DOI： 10.11470/jsapmeeting.2016.1.0_3624

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DOI： 10.11470/jsapmeeting.2016.1.0_3623

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Surface Science Society of Japan  

In recent years, CMOS image sensor has been widely used for ubiquitous devices such as smart-phone and tablets. However, CMOS image sensors performance are dramatically influenced by process induced defects such as metallic impurities related deep level defects in the space-charge region. Thus, it is extremely important to study metallic impurities influence on CMOS image sensor performance and to develop effectiveness metallic impurities gettering technique. In this article, we introduce our new proximity gettering technique for advanced CMOS image sensor by using a carbon cluster ion implantation technique. In addition, we demonstrate that the carbon cluster ion implanted silicon wafer has high gettering capability of oxygen, hydrogen and metallic impurity after CMOS simulation heat treatment.

DOI： 10.1380/jsssj.37.104

DOI： 10.7567/jjap.55.121301_references_DOI_A1kX5CyECs6ZI9ijkcSWwB96HAO

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Other Link： http://id.ndl.go.jp/bib/027198424

Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：The Japan Society of Applied Physics  

We demonstrate the progress of gettering technology for silicon wafers. Gettering technology has been progressing for the control of contamination due to heavy metal impurities during the silicon semiconductor device processing and for the improvement of device yield.

In recent years, CMOS imaging devices have been widely used for mobile communication devices such as smartphones and tablets. However, CMOS imaging device performance is dramatically influenced by metal impurity contamination in the device process. Thus, it is extremely important to study the influence of metal impurities on device performance and to develop metal impurity gettering technology.

In this article, we report the current status of gettering technology trends for advanced CCD/CMOS imagers. In addition, we introduce our new proximity gettering technology for high sensitivity CCD/CMOS imagers by using a carbon cluster ion irradiation technique.

DOI： 10.11470/oubutsu.84.7_628

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