Koji Kita 研究室

主宰者：Koji Kita

東京大学

AI 要約（直近 5 年の研究成果）

Kita研究室は、半導体デバイスの性能を向上させるための界面制御と薄膜プロセスの開発を主な研究テーマとしています。特に、次世代パワー素子の中核となるシリコンカーバイド（SiC）やガリウム酸化物などの広バンドギャップ半導体と、それらの上に形成される酸化物層との界面における欠陥の形成メカニズムを解明しています。赤外分光法やX線回折などの分析手法を用いて、熱処理条件や窒化プロセスが表面の結晶構造や欠陥密度にどのように影響するかを系統的に調査しています。研究の主な焦点は、SiC/酸化物界面に生成される炭素関連の欠陥や不純物の制御、および窒素を用いた表面パッシベーション（欠陥の無害化）プロセスの最適化にあります。例えば、酸化プロセスや高温焼成時の酸素分圧の調整、さらにはホウ素などの添加元素の役割を詳細に検討しており、これらの知見に基づいて電気特性の改善につながるプロセス設計指針を提案しています。さらに、強誘電体HfO2薄膜や酸化物ペロブスカイト多層膜といった機能性薄膜の結晶性や分極特性を制御する研究も展開しており、原子層成膜法などの先端プロセス技術との組み合わせにより、デバイス応用に適した材料開発を進めています。

※ AI（Claude）が、公開されている論文要旨から研究の問い・手法・主要な発見を事実情報として抽出・再構成して自動生成しています。誤りを含む可能性があるため、正確性は研究室公式情報でご確認ください。

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研究成果（63 件）

[2026] Mitigating Intrinsic Fixed-Charge-Induced $\mathrm{V}_{\text{f b}}$ Fluctuation Using a “Neutral $\text{TiO}_{2}$ Dipole” Layer
DOI: https://doi.org/10.1109/vlsitechnologyandcir65830.2026.11577365
[2026] Effects of oxidant selection for atomic layer deposition on impurity removal and crystallinity of as-grown Hf1− x Zr x O2 thin films
DOI: https://doi.org/10.1116/6.0005362
[2025] Clarification of the Mechanism of Crystallization by the Topmost ZrO2 Layer in ZrO2/Hf0.5Zr0.5O2 Stack
DOI: https://doi.org/10.7567/ssdm.2025.ps-01-09
[2025] Anomalous formation of carbon-related defects during high temperature Ar annealing in 4H-SiC enhanced by prior thermal oxidation
DOI: https://doi.org/10.35848/1882-0786/ae0bee
[2025] (Invited) Consideration on 4H-SiC Surface Nitridation Processes for Passivating SiC/SiO 2 Interface Traps
DOI: https://doi.org/10.1149/ma2025-02361735mtgabs
[2025] Detection of defects with carbon–carbon single-bonds in near-surface region of SiC induced by low-oxygen-partial-pressure annealing by using FTIR
DOI: https://doi.org/10.35848/1882-0786/adb2db
[2025] Consideration on 4H-SiC surface nitridation reactions for designing more efficient SiO2/SiC interface defect passivation processes
DOI: https://doi.org/10.7567/ssdm.2025.m-1-01
[2025] Study on 4H-SiC (0001) MOS Interface Characteristics with Direct NO Oxynitridation Considering SiC Surface Reaction Kinetics
DOI: https://doi.org/10.7567/ssdm.2025.m-1-04
[2024] (Invited) Role of Oxidant Gas for Atomic Layer Deposition of HfxZr1−XO2 Thin Films on Ferroelectricity of Metal-Ferroelectric-Metal Capacitors
DOI: https://doi.org/10.1149/11302.0051ecst
[2024] (Invited) Role of Oxidant Gas for Atomic Layer Deposition of HfxZr1−XO2 Thin Films on Ferroelectricity of Metal-Ferroelectric-Metal Capacitors
DOI: https://doi.org/10.1149/ma2024-01211303mtgabs

続きを表示（残り 53 件）

[2024] Investigating the mechanism of SiO2/4H-SiC interface traps passivation by boron incorporation through FT-IR analysis of near-interface SiO2
DOI: https://doi.org/10.35848/1882-0786/ad652a
[2024] (Invited) Consideration on Gate Stack Formation Processes of Ultrawide Bandgap Ga2O3 with SiO2 Dielectric Layer
DOI: https://doi.org/10.1149/ma2024-01211299mtgabs
[2024] Understanding of the effect of thermodynamic conditions on 4H-SiC surface nitridation kinetics based on modeling of surface nitridation kinetics
DOI: https://doi.org/10.7567/ssdm.2024.d-5-02
[2024] Detection of carbon-related defects in near-surface region of SiC induced by low-oxygen-partial-pressure annealing
DOI: https://doi.org/10.7567/ssdm.2024.d-6-04
[2024] Dependence of the incorporated boron concentration near SiO2/4H–SiC interface on trap passivation reduction
DOI: https://doi.org/10.1063/5.0200844
[2024] Low-Temperature Annealing in O2 to Annihilate the Fixed Charges in 4H-SiC/SiO2 Interface Induced by High-N-Density Nitridation Process
DOI: https://doi.org/10.1109/led.2024.3400954
[2024] Enhancement of remnant polarization in ferroelectric HfO2 thin films induced by mechanical uniaxial tensile strain after the crystallization process
DOI: https://doi.org/10.35848/1882-0786/ad379a
[2024] Comparative study of mechanical stress-induced flat-band voltage change in MOS capacitor and threshold voltage change in MOSFET fabricated on 4H-SiC (0001)
DOI: https://doi.org/10.35848/1347-4065/ad2aa6
[2023] Electroless Plating on Coiled Algae to Copper Microcoils and Their Terahertz Electromagnetic Wave Absorption
DOI: https://doi.org/10.23919/icep58572.2023.10129765
[2023] Relaxation of the Distorted Lattice of 4H-SiC (0001) Surface by Post-Oxidation Annealing
DOI: https://doi.org/10.4028/p-n0q5nl
[2023] Fine Pitch Micro Via Interconnection with Reliable Electroless/electric Cu plating Layers Combined with High Power DUV Picosecond Laser for Organic Substrates
DOI: https://doi.org/10.1109/ectc51909.2023.00236
[2023] Study of Cu Micro-via by TOF-SIMS and STEM
DOI: https://doi.org/10.23919/icep58572.2023.10129689
[2023] Effect of Ni additive on electroless Cu quality for high density interconnect PCB substrate
DOI: https://doi.org/10.23919/icep58572.2023.10129713
[2023] Structural distortion in ferroelectric HfO2 – The factor that determines electric field-induced phase transformation
DOI: https://doi.org/10.1016/j.sse.2023.108639
[2023] Preface: Special issue on control of semiconductor interfaces (ISCSI-IX)
DOI: https://doi.org/10.1016/j.mssp.2023.107386
[2023] Low-temperature post-nitridation O 2 annealing to reduce the fixed charge density while maintaining the high SiC surface N density
DOI: https://doi.org/10.7567/ssdm.2023.n-5-01
[2023] Remnant Polarization Enhancement in Ferroelectric HfO2 Thin Films Induced by Mechanical Uniaxial Tensile Strain during Polarization Switching
DOI: https://doi.org/10.7567/ssdm.2023.ps-2-04
[2023] Structural investigation of nanovoids around the interface of micro-vias by spherical aberration corrected scanning transmission electron microscopy
DOI: https://doi.org/10.1016/j.microrel.2023.115231
[2023] Anomalous Impact of Mechanical Uniaxial Stress on Threshold Voltage of 4H-SiC (0001) MOSFET
DOI: https://doi.org/10.7567/ssdm.2023.n-5-03
[2023] The Influence of Boron Concentration on the Reduction of SiO 2/4H-SiC MOS Interface Defect Density with Preserved Flatband Voltage Stability
DOI: https://doi.org/10.7567/ssdm.2023.n-5-05
[2023] (Invited) Design of Surface Oxidation and Nitridation Reactions on 4H-SiC for the Advanced SiC Gate Stack Formation Processes
DOI: https://doi.org/10.1149/ma2023-02301535mtgabs
[2023] Verification of modulation mechanism of the interfacial dipole effect by changing the stacking sequence of monatomic layers in perovskite oxides
DOI: https://doi.org/10.1063/5.0169529
[2023] Opportunity to achieve an efficient SiC/SiO2 interface N passivation by tuning the simultaneous oxidation modes during the SiC surface nitridation in N2 + O2 annealing
DOI: https://doi.org/10.1016/j.sse.2023.108815
[2023] Effects of oxidant gas for atomic layer deposition on crystal structure and fatigue of ferroelectric HfxZr1−xO2 thin films
DOI: https://doi.org/10.1016/j.sse.2023.108801
[2023] Manipulation of Local Band Alignment Distribution by Controlling the Stacking Sequence in Dipole Layer at Perovskite Oxide Interface Characterized by Conductive AFM
DOI: https://doi.org/10.7567/ssdm.2023.m-6-05
[2022] Correlation between Dipole Layer Formation and Surface Terminating Crystal Face in Perovskite Oxide Epitaxial Stacks Clarified by Lateral Force Microscopy
DOI: https://doi.org/10.7567/ssdm.2022.b-6-01
[2022] (Invited, Digital Presentation) Clarification of Possible Factors to Determine Flat-Band Voltage in 4H-SiC Gate Stacks with Nitrogen Passivation Processes
DOI: https://doi.org/10.1149/ma2022-01191066mtgabs
[2022] (Digital Presentation) Study on the Electrical Characteristics and Band Diagrams of Ga2O3 MOS Gate Stacks
DOI: https://doi.org/10.1149/ma2022-01181038mtgabs
[2022] Unexpected fixed charge generation by an additional annealing after interface nitridation processes at the SiO 2 /4H-SiC (0001) interfaces
DOI: https://doi.org/10.35848/1347-4065/ac68cd
[2022] Improvement of SiO2/4H-SiC MOS Interface Characteristics via a Concentration-Tunable Boron Incorporation Process
DOI: https://doi.org/10.7567/ssdm.2022.j-6-08
[2022] 4H-SiC surface nitridation kinetic model in high temperature N2 (+O2) annealing focusing on the effects of annealing temperature and O2 partial pressure
DOI: https://doi.org/10.7567/ssdm.2022.j-6-06
[2022] Characterization of deep traps in the near-interface oxide of widegap metal–oxide–semiconductor interfaces revealed by light irradiation and temperature change
DOI: https://doi.org/10.35848/1347-4065/ac6564
[2021] Flat-band voltage shift of 4H-SiC MOS capacitors induced by interface dipole layer formation at the oxide-semiconductor and oxide-oxide interfaces
DOI: https://doi.org/10.1016/j.sse.2021.108115
[2021] Opportunity for band alignment manipulation of perovskite oxide stacks by interfacial dipole layer formation
DOI: https://doi.org/10.1016/j.sse.2021.108128
[2021] Impacts of band alignment change after interface nitridation on the leakage current of SiO2/4H-SiC (0001) and (1100) MOS capacitors
DOI: https://doi.org/10.35848/1882-0786/ac16b9
[2021] Considerations on the kinetic correlation between SiC nitridation and etching at the 4H-SiC(0001)/SiO2 interface in N2 and N2/H2 ambient
DOI: https://doi.org/10.7567/ssdm.2021.d-4-05
[2021] Considerations on the kinetic correlation between SiC nitridation and etching at the 4H-SiC(0001)/SiO 2 interface in N 2 and N 2 /H 2 annealing
DOI: https://doi.org/10.35848/1347-4065/ac4357
[2021] Comparative Study of Hall Effect Mobility in Inversion Layer of 4H-SiC MOSFETs With Nitrided and Phosphorus-Doped Gate Oxides
DOI: https://doi.org/10.1109/ted.2021.3125284
[2021] Impacts of Al2O3/SiO2 Interface Dipole Layer Formation on the Electrical Characteristics of 4H-SiC MOSFET
DOI: https://doi.org/10.1109/led.2021.3125945
[2021] (Invited) Study on Impact of MOS Interface Passivation Processes on Band Alignment and Flat-Band Voltage of 4H-SiC Gate Stacks
DOI: https://doi.org/10.1149/ma2021-0230940mtgabs
[2021] Effects of Sintered Temperature of Kairagi on Sensory attributes of Grape Juice
DOI: https://doi.org/10.1299/jsmemecj.2021.s042-05
[2021] (Invited) Study on Impact of MOS Interface Passivation Processes on Band Alignment and Flat-Band Voltage of 4H-SiC Gate Stacks
DOI: https://doi.org/10.1149/10404.0193ecst
[2021] Positive threshold voltage shift of 4H-SiC MOSFET induced by Al2O3/SiO2 interface dipole layer formation
DOI: https://doi.org/10.7567/ssdm.2021.d-4-02
[2021] Considerations on competition between SiC surface nitridation and etching at SiO 2 /SiC interface induced by high-temperature N 2 annealing
[2021] Positive V FB shift of 4H-SiC MOS capacitors induced by Al 2 O 3 /SiO 2 interface dipole layer formation
[2021] Changing of structural distortion and stabilization of ferroelectric phase in cap-annealed HfO 2 thin films characterized by in-plane and out-of-plane XRD
[2021] MOS structure fabrication on 4H-SiC surface after high temperature N 2 + H 2 annealing
[2021] Differnce between 4H-SiC/SiO 2 nitrided interface structural changes by high temperature annealing and γ-ray irradiation
[2021] Direct Evidence of Electric Field driven Phase Transformation in the Waking-up Process of Ferroelectric HfO 2 Characterized by Conventional X-ray Diffraction
[2021] Accurate estimation of MOS itenrface fixed charge density based on UPS analysis of electric structure of β -Ga 2 O 3
[2021] Significant change of interface dipole effect at perovskite oxide epitaxial interface by the number of charge-introducing atomic layer
[2021] Evidence of ferroelectric HfO2 phase transformation induced by electric field cycling observed at a macroscopic scale
DOI: https://doi.org/10.1016/j.sse.2021.108086
[2021] Anomalous structural distortion – a possible origin for the waking-up of the spontaneous polarization in ferroelectric HfO 2
DOI: https://doi.org/10.35848/1347-4065/ac085c

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AI 要約（直近 5 年の研究成果）

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関連研究室(8 件)

研究成果（63 件）

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