Study on the Ultrasonic Bonding Process Using Molecular Dynamics Simulation
Yasushi Sasajima; Shingo Hatakeyama; Chihiro Iwamoto, Lead
Journal of Electronic Materials, Mar. 2025, [Reviewed]

Molecular Dynamics Simulation of High-Energy Beam Irradiation of SiO2 Single Crystal with Three Different Morphologies: No Free Surface, with a Free Surface, and Thin Films
Shunya Otsuka; Satoshi Kimata; Yasushi Sasajima; Norito Ishikawa, Corresponding
ECS Journal of Solid State Science and Technology, 01 Nov. 2024, [Reviewed]

Optimization of Pore Formation Process of Lotus Aluminum by Phase Field Simulation
K. Takahashi; K. Yamaguchi; Y. Sasajima; T. Ikeda, Corresponding, ロータスアルミニウムのポア成長の最適化をフェーズフィールドシミュレーションにより行った。
ECS Advances, 01 Sep. 2023, [Reviewed]

Simulation of the Pressure Bonding Process Using the Phase-field Crystal Method
Yasushi Sasajima; Ryosuke Onozwa; Shingo Hatakeyama; Chihiro Iwamoto, Lead, 圧着過程をフェーズフィールドクリスタル法によりシミュレートした。
ECS Journal of Solid State Science and Technology, 01 Jul. 2023, [Reviewed]

A New Thin High Voltage Transformer Using FPC
指田和之; 指田和之; 竹原奈津紀; 大貫仁; 篠嶋妥,

トランスはさまざまな産業機器用電源に搭載されているが，小型化，薄型化が強く望まれている。本研究では，FPC (Flexible Printed Circuits)を用いた小型，薄型の高圧トランスの開発を行った。高圧トランスは多くの巻数が必要となるため，隣り合う線との間に形成される静電容量（浮遊容量）が増大して，自己共振周波数が低くなり，スイッチング周波数を高めることができない。さらに高耐圧が必要なため，小型化が難しいという問題がある。本研究ではFPCの高柔軟性，高耐圧性およびファインピッチパターニング特性に着目して，高圧トランスへの適用性を検討した。巻線間の耐圧を保持しながら，浮遊容量を減らす方策およびFPCを折り畳む新構造を見出し，従来品よりも浮遊容量を小さくすることで，自己共振周波数が高い薄型の高圧トランスを開発した。

, 一般社団法人エレクトロニクス実装学会
エレクトロニクス実装学会誌, 01 Jan. 2023

Optimization of the Surface Structure of the SiC Substrate for SiC-Ni Melt-bonding Using Simulation by Phase-Field Method
Yasushi Sasajima; Kyohei Iwata; Kazuki Shinozuka; Jin Onuki, Lead
ECS J. Solid State Sci. Technol., Dec. 2022, [Reviewed]

Enhancement of Power Cycle Life Time of Power Modules Using Water Cooled Multilayer Ceramic Substrates
指田和之; 指田和之; 竹原奈津紀; 大貫仁; 篠嶋妥, 一般社団法人エレクトロニクス実装学会
エレクトロニクス実装学会誌, 01 May 2022, [Reviewed]

Pore Formation and Shape Control Simulation of Lotus Aluminum by Phase Field Method　　　　　　　　　　　　　　　
Kei Takahashi; Yasushi Sasajima; and Teruyuki Ikeda, Corresponding
ACS Omega, Apr. 2022, [Reviewed]

Simulation of Pressure-imposed Bonding Process by Phase Field Crystal Method
篠嶋妥; 小野澤亮祐; 畠山慎悟; 岩本知広
Symposium on Microjoining and Assembly Technology in Electronics, 2022

Nanopore Formation in CeO2 Single Crystal by Ion Irradia-tion: A Molecular Dynamics Study
Yasushi Sasajima; Ryuichi Kaminaga; Norito Ishikawa; Akihiro Iwase, Lead, The nanopore formation process that occurs by supplying a thermal spike to single crystal CeO2 has been simulated using a molecular dynamics method. As the initial condition, high thermal energy was supplied to the atoms in a nano-cylinder placed at the center of a fluorite structure. A nanopore was generated abruptly at around 0.3 ps after the irradiation, grew to its maximum size at 0.5 ps, shrank during the time to 1.0 ps, and finally equilibrated. The nanopore size increased with increasing effective stopping power gSe (i.e., the thermal energy deposited per unit length in the specimen), but it became saturated when gSe was 0.8 keV/nm or more. This finding will provide useful information for precise control of the size of nanopores. Our simulation confirmed nanopore formation found in the actual experiment, irradiation of CeO2 with swift heavy ions, but could not reproduce crystalline hillock formation just above the nanopores.
Quantum Beam Sci., Nov. 2021, [Reviewed]

Electric Field Dependence Mechanism for Cosmic Ray Failure in Power Semiconductor Devices
Tetsuo Oda; Taiga Arai; Tomoyasu Furukawa; Masaki Shiraishi; and Yasushi Sasajima, IEEE
IEEE Transactions on Electron Device Letters, May 2021, [Reviewed]

Optimization of the Surface Structure of the Si Substrate for Si-Al Bonding Using Simulation by the Phase Field Method
Kyohei Iwata; Ryusuke Yuchi; Yasushi Sasajima and Jin Onuki, Corresponding
Journal of Electronic Materials, May 2021, [Reviewed]

Simulation of Grain Coarsening Process in Copper Wiring by Phase Field Method
Yasushi Sasajima; Ryusuke Yuchi and Jin Onuki, Lead
ECS J. Solid State Sci. Technol., 17 Feb. 2021, [Reviewed]

Effective pore size control method for lotus aluminum by phase field simulation
K.Iitsuka; Y. Sasajima and T.Ikeda, Corresponding, 一方向凝固中のアルミニウム中のポアの成長過程を多相ふぇーあうフィールド法によりシミュレートした。固液界面の移動速度（V)と温度勾配（G)のポアサイズに対する影響は実際の実験とよく一致した。G一定の下でVをポア成長レートに負比例させて制御すると、ポアは幅を一定にして成長することを見出した。
Materials Science & Engineering B, Aug. 2020, [Reviewed]

A novel lining method for eliminating plastic deformation and protrusion of copper in Cu-TSV using FEM analysis
Yazdan Zare; Yasushi Sasajima and Jin Onuki, Cuスルーシリコンビア（TSV)の熱処理に伴うCu突出を抑制するバリア膜の探索を行った。三層構造膜とし、内側は基体であるシリコンよりも高いヤング率、外側は銅よりも高い熱膨張率、中間層はシロキサンのように柔らかい樹脂層とすれば、Cu突出をほぼ完全に抑制できることを発見した。
J. Electon. Mater., Mar. 2020, [Reviewed]

Crystal Structure Analysis of Irradiated Ni3Al Using Molecular Dynamics Simulation
Ahmad Ehsan Mohd Tamidi; Yasushi Sasajima and Akihiro Iwase, Corresponding, Ni3Alに熱スパイクを与えた後の原子構造変化を調べた。照射によりL12規則構造が不規則構造に変わり、それに伴って硬度が減少することが分かった。この結果は実際の照射実験と訂正的に一致することを指摘した。
Materials Transactions, Jan. 2020, [Reviewed]

Evaluation of the Cu-TSV barrier materials as a solution to copper protrusion
Yazdan Zare; Yasushi Sasajima and Jin Onuki, Cuスルーシリコンビア（TSV)の熱処理に伴うCu突出を抑制するバリア膜の探索を行った。単一膜では、基体であるシリコンよりも高いヤング率と、銅よりも高い熱膨張率を同時に実現する必要があることを指摘した。
J. Electon. Mater., Dec. 2019, [Reviewed]

Material Report : R&D ロータス型多孔質熱電材料を用いた新しい熱電変換デバイスの可能性
池田 輝之; 永野 隆敏; 篠嶋 妥, シーエムシー出版
機能材料, Jul. 2019, [Reviewed]

Effects of Electroplating at Lower Leveler and Suppressor Contents on the Formation of Very Low Resistivity Narrow Cu Interconnects
R. Miyamoto; K. Tamahashi; T. Inami; Y. Sasajima and J. Onuki, Corresponding, 電気めっきにおいてレベラーおよびサプレッサー添加剤を同時に低減した場合に、極細銅配線の低抵抗率化に相加的に正の影響を及ぼすことを明らかにした。
Journal of The Electrochemical Society, Mar. 2019, [Reviewed]

High-Temperature Cycle Durability of Superplastic Al-Zn Eutectoid Solder Joints with Stress Relaxation Characteristics for SiC Power Semiconductor Devices
K. Saito; K. Tamahashi; T. Inami; M. Kobiyama; Y. Sasajima; J. Onuki; and Y. Kawamata, SiCパワー半導体デバイスのための、応力緩和特性を有する超塑性Al-Zn共析はんだ接合の高温サイクル寿命を評価し、その有用性を実証した。
IEEE Electron Device Letters, Feb. 2019, [Reviewed]

General Expression for Plasma Extraction Transit-Time (PETT) Oscillations from Silicon Bipolar Power SemiconductorDevices
K. Saito; T. Wada; and Y. Sasajima, Last, シリコンバイポーラパワー半導体デバイスからのプラズマ励起遷移時間（PETT)振動を記述する一般的定式化を行い、その抑止方法を提示した。
IEEE Trans. Electron Devices, Feb. 2019, [Reviewed]

Structure analysis of the defects generated by a thermal spike in single crystal CeO2: A molecular dynamics study
Y. Sasajima; N. Ajima; R. Kaminaga; N. Ishikawa; A. Iwase, Lead, セリアの単結晶において熱スパイクにより生成する欠陥を分子動力学法によりシミュレートし、構造解析を行った。
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, Dec. 2018, [Reviewed]

The Protrusion Behaviors in Cu-TSV during Heating and Cooling Process　　　　　　　　　　　　　　　
Bin Liu; Akira Satoh; Kunihiro Tamahashi; Yasushi Sasajima; Jin Onuki, Corresponding, シリコン貫通電極（ＴＳＶ：Ｔhｒｏｕｇｈ Ｓｉｌｉｃｏｎ Ｖｉａ）における銅コアが熱処理時につき出す現象の原因を実験及び有限要素法計算により明らかにした。
Transactions of The Japan Institute of Electronics Packaging, Jun. 2018, [Reviewed]

Simplified Model Analysis of Self-Excited Oscillation and Its Suppression in a High-Voltage Common Package for Si-IGBT and SiC-MOS
Katsuaki Saito; Tomoyuki Miyoshi; Daisuke Kawase; Seiichi Hayakawa; Toru Masuda; Yasushi Sasajima, This paper presents the analysis of a simplified model for the design of a module structure that avoids the risk of self-excited oscillation (SE-Osc). A necessary and sufficient simplified model that can extract the critical oscillation mode is proposed based on a comparison of several simplifying steps. The differential equation of the simplified model is solved, and the solution is plotted in the frequency domain to analyze the oscillatory conditions. The simplified model is verified via a time-domain full-model simulation modeled by 3-D electromagnetic simulation and solved by finite-element simulation. Measurements of test modules show consistent oscillatory conditions and frequency. SE-Osc modes are eliminated by reducing the inductance connected to the emitter and increasing the inductance connected to the collector. Increasing the ratio of CCE to CGC increases the risk of self-exciting oscillation. Suppressions of SE-Osc from a common package design with state-of-the-art Si-insulated gate bipolar transistors (IGBTs) presenting small feedback capacitance, SiC-MOS, and hybrids of state-of-art Si-IGBTs and SiC-Schottky barrier diodes are verified., Institute of Electrical and Electronics Engineers Inc.
IEEE Transactions on Electron Devices, 01 Mar. 2018, [Reviewed]

Nano-Structure-Controlled Very Low Resistivity Cu Wires Formed by High Purity and Optimized Additives
Jin Onuki; Kunihiro Tamahashi; Takashi Inami; Takatoshi Nagano; Yasushi Sasajima; Shuji Ikeda, Resistivity increase in nano-level Cu wires is becoming a critical issue for high speed ULSIs. We have established a new manufacturing process utilizing very high purity 9N electrolyte and optimized additives to control nano-structures of Cu wires, and we realized Cu wires for practical use with 50% lower resistivity than those made with the conventional process. Using STEM analyses and phase field simulation, we also ascertained the reason for getting the very low resistivity Cu wires., Institute of Electrical and Electronics Engineers Inc.
IEEE Journal of the Electron Devices Society, 27 Feb. 2018, [Reviewed]

Strength evaluation on the interface of precipitates with segregated hydrogen in Al-Mg-Zn alloys by ab initio calculation
Takatoshi Nagano; Yuta Kawasaki; Yasushi Sasajima; Goroh Itoh, Ab initio calculation of the tensile deformation of Al-Zn-Mg alloy models was performed to clarify the mechanism for hydrogen embrittlement in the Al-Zn-Mg alloy. The atomistic models of Al/MgZn2 boundaries containing a hydrogen atom, which the authors obtained previously, were used as the initial stable structures with hydrogen segregated at η1, η2, η4 interfaces (notation used by J. Gjønnes and Chr. J. Simensen). The models were strained uniaxially at a constant rate and their total energies after the structural relaxation were calculated by the ab initio method. It has been found that the hydrogen atom trapped near the Al matrix/MgZn2 precipitate interface deteriorates the strength of the Al-Zn-Mg alloys by weakening the bonding strength between Al and Mg-Zn. The authors have proposed that the interface strength can be estimated by the maximum of the derivative of the cohesive energy per unit area and have found that η4 shows the highest strength under tensile deformation. The proposed criteria can be applied to estimate the interface strength of various materials., Japan Institute of Light Metals
Keikinzoku/Journal of Japan Institute of Light Metals, 2018, [Reviewed]

Phase-field simulation of the Si precipitation process in Mg2Si under an applied stress　　　　　　　　　　　　　　　
Bin Liu; Teruyuki Ikeda; Yasushi Sasajima, Corresponding, 熱電材料として有望なMg2Siについて、外部応力を印加して微細組織を制御するために、Si析出過程をフェーズフィールド法により計算した。適切な外部応力を印加することにより所望の微細組織が実現できる可能性を指摘した。
Mater. Sci. Eng. B-Adv., Jan. 2018, [Reviewed]

第一原理計算によるAl-Zn-Mg合金中の析出物水素偏析界面における強度評価
永野 隆敏; 川崎 優太; 篠嶋 妥; 伊藤 吾朗, 第一原理計算によってAl-Zn-Mg合金中の析出物水素偏析界面における強度評価を行い、実験と一致する結果を得た。, 一般社団法人 軽金属学会
軽金属, 2018, [Reviewed]

ロータスアルミニウムにおけるポア成長のフェーズフィールドシミュレーション
劉 濱; 池田 輝之; 篠嶋 妥, Last, ロータスアルミニウムにおけるポア成長のフェーズフィールドシミュレーションが可能であることを示した。, 一般社団法人 軽金属学会
軽金属, 2018, [Reviewed]

Screening of Undesirable Elements Raising the Electrical Resistivity in Very Narrow Cu Wires by Ab Initio Calculation
Takatoshi Nagano; Kunihiro Tamahashi; Takashi Inami; Yasushi Sasajima; Jin Onuki, We estimated segregation energy for compound impurities at the grain boundary in very narrow Cu wires using the ab initio calculation. From the calculation results, we clarified that the impurities such as FeO, Fe(ClO), TiO and Ti(ClO) have a strong segregation tendency at the Cu grain boundaries. The FE-TEM observation results of the Cu wires with Fe impurity atoms confirmed that the impurity atoms led to smaller grain sizes than the impurity-free case. The resistivity was measured as a function of the Cu wire width for various Fe impurity concentrations and the wire resistivity became higher with increased impurity concentration. (C) 2017 The Electrochemical Society. All rights reserved., ELECTROCHEMICAL SOC INC
J. Electrochem. Soc., 01 Sep. 2017, [Reviewed]

Nano-Structure-Controlled Very Low Resistivity Cu Wires Formed by High Purity Electrolyte and Optimized Additives
Jin Onuki; Kunihiro Tamahashi; Takashi Inami; Takatoshi Nagano; Yasushi Sasajima; Shuji Ikeda, Resistivity increase in nano-level Cu wires is becoming a critical issue for high speed ULSIs. We have established the new manufacturing process utilizing very high-purity 9N electrolyte and optimized additives to control nano-structures of Cu wires, and we realized Cu wires with resistivity 50% lower than that of wires made by a conventional process. We also have ascertained the reason for getting very low resistivity Cu wires by STEM analyses and first-principle simulation., IEEE
2017 IEEE ELECTRON DEVICES TECHNOLOGY AND MANUFACTURING CONFERENCE (EDTM), 2017, [Reviewed]

熱的照射下にあるAl-Cu合金におけるθ' 析出相の成長過程のフェーズフィールドシミュレーション　　　　　　　　　　　　　　　
リュウ ビン; 篠嶋 妥; 岩瀬 彰宏, Corresponding, フェーズフィールド法を用いてAｌ-Cu2元系合金に熱的照射を行うことによって起こるθ′析出相の成長過程をシミュレートし,局所的な組織制御の可能性を指摘した。
日本金属学会誌, Aug. 2016, [Reviewed]

第一原理計算によるAl-Zn-Mg合金中の水素の存在位置の解析　　　　　　　　　　　　　　　
永野 隆敏; 篠嶋 妥; 伊藤 吾朗, 第一原理計算を用いて,Al粒内モデル, Al/Al粒界モデルとAl/析出物粒界モデルを作成し,それぞれにおける水素の存在しやすさを形成エネルギーにより比較検討した。Al-Mg-Zn合金における水素原子は、MgZn2析出相との粒界面において半整合界面を選択する傾向があることを明らかにした。
軽金属, Jul. 2016, [Reviewed]

The Relationship between Nanocluster Precipitation and Thermal Conductivity in Si/Ge Amorphous Multilayer Films:,Effects of Cu Addition
Ahmad Ehsan Mohd Tamidi and Yasushi Sasajima, Last, We have used a molecular dynamics technique to simulate the relationship between nanocluster precipitation and thermal conductivity in Si/Ge amorphous multilayer films, with and without Cu addition. In the study, the Green-Kubo equation was used to calculate thermal conductivity in these materials. Five specimens were prepared: Si/Ge layers, Si/(Ge + Cu) layers, (Si + Cu)/(Ge + Cu) layers, Si/Cu/Ge/Cu layers, and Si/Cu/Ge layers. The number of precipitated nanoclusters in these specimens, which is defined as the number of four-coordinate atoms, was counted along the lateral direction of the specimens. The observed results of precipitate formation were considered in relation to the thermal conductivity results. Enhancement of precipitation of nanoclusters by Cu addition, that is, densification of four-coordinate atoms, can prevent the increment of thermal conductivity. Cu dopant increases the thermal conductivity of these materials. Combining these two points, we concluded that Si/Cu/Ge is the best structure to improve the conversion efficiency of the Si/Ge amorphous multilayer films., HINDAWI PUBLISHING CORP
Journal of Nanomaterials, 01 Apr. 2016, [Reviewed]

Ab initio calculation study on the site of hydrogen in Al-Zn-Mg alloys
Takatoshi Nagano; Yasushi Sasajima; Goroh Itoh, Ab initio calculation study on the site of hydrogen in Al-Zn-Mg alloys was performed to clarify the mechanism of hydrogen segregation, aiming to understand the mechanism for hydrogen embrittlement in Al-Zn-Mg alloys. In order to determine stable structures with hydrogen at grain boundaries as well as inside the grain, atomistic models of Al matrix, Al/Al and Al/MgZn2 boundaries containing a hydrogen atom were constructed, and their total energies as well as stable structures were calculated by the ab initio method. We defined and estimated the formation energy of hydrogen and compared the stability of segregated hydrogen in Al matrix, Al/Al and Al/MgZn2 boundaries. We found that hydrogen has a tendency to segregate in Al/MgZn2 boundaries, η1, η4, η2 (notation used by J. Gjønnes and Chr. J. Simensen) in this order. This is in accord with the thought that hydrogen is prone to be trapped on a semicoherent boundary, which was previously concluded from experimental results., Japan Institute of Light Metals
Keikinzoku/Journal of Japan Institute of Light Metals, 2016, [Reviewed]

Phase Field Simulation of Growth Process of theta' Precipitation Phase in Al-Cu Alloy under Thermal Irradiation
Bin Liu; Yasushi Sasajima; Akihiro Iwase, The theta' precipitation process of Al-Cu alloy was simulated with the coupling model of a phase field and a concentration field during isothermal annealing and under thermal irradiation. This model successfully described the theta' precipitation process under isothermal annealing at 423 K and 473 K, including the growth rate of the theta' precipitates. The model was used also to simulate the theta' precipitation process under thermal irradiation at 473 K and it was found that the size and the distribution of the theta' precipitates can be controlled locally by this process. The simulation results also indicated that the heat sink process around the irradiated area is important to achieve a precisely. controlled precipitated structure., JAPAN INST METALS
JOURNAL OF THE JAPAN INSTITUTE OF METALS, 2016, [Reviewed]

Simulation of the Si Precipitation Process in Mg2Si Using a Phase-Field Kinetic Model
Bin Liu; Teruyuki Ikeda; Yasushi Sasajima, The Si precipitation process in an Mg2Si matrix has been simulated by the phase-field kinetic model, considering the eigen strain at the interface between precipitates and the matrix. We observed that the shape of the precipitate changed during the course of heat treatment from circular to lenticular. As the Si precipitate grew larger, the adjacent precipitate aggregated to form a lamellar microstructure. This microstructure is suitable for thermo-electric materials because the scattering of phonons will frequently occur at the interface between the Si precipitates and the Mg2Si matrix. Our present simulation suggests drastic improvements of thermo-electric properties of this type of material are possible due to the eigen strain., JAPAN INST METALS
MATERIALS TRANSACTIONS, 2016, [Reviewed]

Computer experiments on radiation strength and radiation enhanced segregation of Al-Si amorphous alloys
Yasushi Sasajima; Naoki Ajima; Kazuaki Momoi; Akihiro Iwase, Computer experiments of irradiated Al-Si alloys were performed to clarify the mechanism of radiation enhanced segregation. The atomic configurations of pure Al, Al-5 at%Si and Al-10 at%Si with amorphous structure after the irradiation of high energy beam were calculated by the molecular dynamics method. We estimated the threshold energies to create voids in pure Al, Al-5 at%Si and Al-10 at%Si as 0.23, 0.25 and 0.25 keV/nm, respectively. This fact means that addition of Si to Al enhances strength against void formation by beam irradiation. We also confirmed that addition of Si to Al gave strong effect on radiation enhanced segregation. The degree of enhancement depended on the degree of dispersion of Si atoms in Al matrix because the Si atoms enhances clustering of the Al atoms surrounding them.
Keikinzoku/Journal of Japan Institute of Light Metals, 2015

Effectiveness of a periodic annealing method to coarsen Cu grains in very narrow trenches
Yasushi Sasajima; Tatsuya Miyamoto; Takatoshi Saitoh; Takahiro Yokoyama and Jin Onuki, Lead, We developed a new annealing method, periodic annealing, to effectively coarsen Cu grains in very narrow trenches. In the periodic annealing method, the temperature of the specimen is elevated at a rapid rate to a target temperature and the temperature is oscillated at a certain periodicity. We identified the best oscillation conditions for the system temperature using the phase field simulation method. The best conditions achieved a 98% increase in the grain diameter of the Cu trench model. A preliminary experiment using an actual 70 nm width wire showed about a 10% increase in the grain diameter, confirming the effectiveness of the periodic annealing method to coarsen Cu grains in very narrow trenches. (C) 2014 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Microelectronic Engineering, 2015, [Reviewed]

Al-Siアモルファス合金の照射耐性と析出促進過程の計算機実験
篠嶋 妥; 安島 直紀; 桃井 一章; 岩瀬 彰宏, Lead
軽金属, 2015, [Reviewed]

Pinning Effect of Fe(ClO) and Ti(ClO) Compounds on Cu Grain Growth in Very Narrow Cu Wires
Takatoshi Nagano; Yasushi Sasajima; Nobuhiro Ishikawa; Kunihiro Tamahashi; Kishio Hidaka and Jin Onuki, We have clarified that the grain growth of Cu in very narrow Cu wires is reduced by the pinning effect of Fe(C10) and Ti(C10) compounds at a grain boundary based on results of a nano-order-analysis of aberration-corrected scanning transmission electron microscope (Cs-corrected STEM) observations and an ab initio calculation. From the calculation, we estimated the segregation energy for the Fe(ClO) and Ti(ClO) compound impurities at the Cu grain boundary. Combining the ab initio calculation and measurement results, we proposed a pinning mechanism to suppress the grain boundary movement. (C) 2015 The Electrochemical Society. All rights reserved., ELECTROCHEMICAL SOC INC
ECS Electrochemistry Letters, 2015, [Reviewed]

Computer simulation of structural modifications induced by highly energetic ions in uranium dioxide
Y. Sasajima; T. Osada; N. Ishikawa; A. Iwase, The structural modification caused by the high-energy-ion irradiation of single-crystalline uranium dioxide was simulated by the molecular dynamics method. As the initial condition, high kinetic energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Basak et al. [C.B. Basak, A.K. Sengupta, H.S. Kamath, J. Alloys Compd. 360 (2003) 210-216] was utilized to calculate interaction between atoms. The supplied kinetic energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. The amorphous track radius R-a was determined as a function of the effective stopping power gS(e), i.e., the kinetic energy of atoms per unit length created by ion irradiation (S-e: electronic stopping power, g: energy transfer ratio from stopping power to lattice vibration energy). It was found that the relationship between R-a and gS(e) follows the relation R-a(2) = aln(gS(e)) + b. Compared to the case of Si and beta-cristobalite single crystals, it was harder to produce amorphous track because of the long range interaction between U atoms. (C) 2013 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, Nov. 2013, [Reviewed]

Cs-Corrected STEM Observation and Atomic Modeling of Grain Boundary Impurities of Very Narrow Cu Interconnect
Takatoshi Nagano; Kunihiro Tamahashi; Yasushi Sasajima; Jin Onuki, Nano-order-analysis of grain boundary in very narrow Cu interconnect was performed for the first time using spherical aberration corrected Scanning Transmission Electron Microscope (Cs-corrected STEM). We focused our attention on both direct observation and ab initio calculation of impurities at the grain boundaries in Cu interconnect which depress the grain growth. STEM observation showed that Cl segregates at grain boundary, and that O exist in both grain boundary and interstitial. We estimated the segregation energy for the impurities at Cu grain boundary, and found that the result coincides with the observed tendency. (C) 2013 The Electrochemical Society. [DOI: 10.1149/2.001306eel] All rights reserved., ELECTROCHEMICAL SOC INC
ECS ELECTROCHEMISTRY LETTERS, 2013, [Reviewed]

Nano-scale analysis of impurities at grain boundary in very narrow Cu wire　　　　　　　　　　　　　　　
Takatoshi Nagano; Kunihiro Tamahashi; Nobuhiro Ishikawa; Yasushi Sasajima and Jin Onuki, Cu粒界への不純物偏析エネルギーの第1原理計算による評価を行い、結果をCs補正STEM観察結果と比較した。ClがCu粒界に偏析し、Oは粒界と粒内のどちらにも存在しており、Cu粒成長をClが阻害することが示唆された。
ECS Electrochemistry Letters, 2013, [Reviewed]

Computer simulation of high-energy-ion irradiation of uranium dioxide　　　　　　　　　　　　　　　
Y.Sasajima; T.Osada; N.Ishikawa; A. Iwase, Lead, UO2単結晶への照射シミュレーションを行った。与えた熱エネルギーが0.3psの間に構造をアモルファスに変えることを見出した。アモルファストラック半径と有効阻止能の関数形を求め、長距離相互作用のためにアモルファストラック形成が困難であることを指摘した。
Nucl. Instr. Meth. B, 2013

Molecular dynamics simulation of fast particle irradiation to the single crystal CeO2
Y.Sasajima; N.Ajima; T.Osada; N.Ishikawa; A. Iwase, Lead, We used a molecular dynamics method to simulate structural relaxation caused by the high-energy-ion irradiation of single crystal CeO2. As the initial condition, we assumed high thermal energy was supplied to the individual atoms within a cylindrical region of nanometer-order diameter located in the center of the single crystal. The potential proposed by Inaba et al. was utilized to calculate interactions between atoms [H. Inaba, R. Sagawa, H. Hayashi, K. Kawamura, Solid State Ionics 122 (1999) 95-103]. The supplied thermal energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it was dissipated in the crystal. We compared the obtained results with those of computer simulations for UO2 and found that CeO2 was more stable than UO2 when supplied with high thermal energy. (C) 2013 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Nucl. Instr. Meth. B, 2013, [Reviewed]

Molecular dynamics simulation of fast particle irradiation to the Gd2O3 - doped CeO2
Y.Sasajima; N.Ajima; T.Osada; N.Ishikawa; A. Iwase, Lead, The structural relaxation caused by the high-energy-ion irradiation of CeO2 with Gd2O3 addition was simulated by the molecular dynamics method. The amount of Gd2O3 was changed from 0 to 25 mol% by 5 mol%. As the initial condition, high thermal energy was supplied to the individual atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The potential proposed by Inaba et al. was utilized to calculate interaction between atoms [H. Inaba, R. Sagawa, H. Hayashi, K. Kawamura, Solid State Ionics 122 (1999) 95-103]. The supplied thermal energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it dissipated in the specimen. By increasing the concentration of Gd2O3, more structural disorder was observed in the sample, which is consistent to the actual experiment. (C) 2013 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Nucl. Instr. Meth. B, 2013

Computer simulation of high-energy-ion irradiation of SiO2　　　　　　　　　　　　　　　
Y.Sasajima; H.Onuki; N.Ishikawa; A. Iwase, Lead, SiO2単結晶への照射シミュレーションを行った。与えた熱エネルギーが0.3psの間に構造をアモルファスに変えることを見出した。アモルファストラック半径と有効阻止能の関数形を求め、四面体クラスター間の結合が弱いためにアモルファストラック形成がSiよりも容易であることを指摘した。
Trans. MRS-J, 2013, [Reviewed]

Computer Simulation of Precipitation Process in Si/Ge Amorphous Multi-layer Films: Effects of Cu addition
Yasushi Sasajima; Junya Murakami; Ahmad Ehsan Bin Mohd Tamidi, Lead, We have simulated the precipitation process in an amorphous Si/Ge multi-layer film, with and without Cu addition, by a molecular dynamics method. Four specimens were prepared for this study: Si/Ge layers, Si/(Ge + Cu) layers, (Si + Cu)/(Ge + Cu) layers and Si/Cu/Ge/ Cu layers. After the multi-layered films became amorphous, we tracked the movement of individual atoms at 1000 K, the annealing temperature. When Cu was present in the Ge layer or both the Si and Ge layers, the precipitation of nano-clusters was less than that in Cu-free Si/Ge layers. We think that the Cu atoms block the precipitation and make the Si and Ge become more stable in the amorphous state. If Cu atoms are note present in a layer, however, like the Si layer in Si/(Ge + Cu) and Si/Cu/Ge/Cu specimens, the precipitation of nano-clusters in the Cu-free layer is enhanced. Therefore we conclude that precipitation of nano-clusters in Si/Ge layers can be controlled by how Cu atoms are added to the amorphous Si/Ge system, and that this will improve the thermoelectric performance. ©2013 The Japan Society for Technology of Plasticity.
Mater. Trans., 2013, [Reviewed]

Search for Barrier Materials for Cu Interconnects in Integrated Circuits
Yasushi Sasajima; Yuki Kimura; Tetsunori Tsumuraya; Takatoshi Nagano and Jin Onuki, Lead, We used the molecular dynamics simulation method to investigate the growth process of Cu polycrystalline films on three substrates Si, Ti and Ru during isothermal annealing. We focused on the influence of the adhesion strength and size mismatch between the substrate and Cu on crystallinity and orientational order of the films. Our simulation results clarified that Ru is an excellent material for the substrate/barrier metal to be used with Cu films. Based on the findings, we proposed a strategy to identify novel barrier materials to be used with Cu interconnect wires. One of the best candidate materials, IrMo, showed good epitaxy of Cu(111) in the ab initio calculation. (C) 2013 The Electrochemical Society. All rights reserved., ELECTROCHEMICAL SOC INC
ECS J. Solid State Sci. Tech., 2013, [Reviewed]

Resistivity Reduction in Very Narrow Cu Wiring
Jin Onuki; Yasushi Sasajima; Kunihiro Tamahashi; YiQing Ke; Shohei Terada; Kishio Hidaka; and Shinji Itoh, Low resistivity 60nm wide Cu wires were realized by the combination of lessening impurities through additive-less plating and high-heating rate annealing. Resistivities of Cu wires made with the new method were about 20% lower than those made by conventional plating with additives and annealing at the same temperature. Low resistivity Cu wires were formed even at temperatures 100k lower than conventional annealing temperatures due to substantial grain growth by high-heating rate annealing in the Cu wires made with additive-less plating., ELECTROCHEMICAL SOC INC
Journal of The Electrochemical Society, 2013, [Reviewed]

Molecular Dynamics Simulation of Grain Growth of Cu Film
Y. Sasajima; J. Onuki, We investigated the growth process of Cu polycrystalline films on three substrates Si, Ti and Ru during isothermal annealing by the molecular dynamics method. We focused on the influence of the adhesion strength and size mismatch between substrate and Cu on crystallinity and orientational order of the film. The present simulation clarified that Ru is excellent material as substare/barrier metal for Cu wire. Based on the findings, a search plot for replacement material of Ru was proposed., ELECTROCHEMICAL SOC INC
ELECTRODEPOSITION OF NANOENGINEERED MATERIALS AND DEVICES 4, 2012, [Reviewed]

Void generation mechanism in Cu filling process by electroplating for ultra fine wire trenches
Yasushi Sasajima; Takatoshi Satoh; Kunihiro Tamahashi; Jin Onuki, Lead, In the Cu filling process by electroplating for ultra-fine wire trenches in LSIs, voids are generated for narrow wires of less than 80nm width. We observed the Cu film formation process as a function of time and found that the flow of Cu electrolyte solution is not homogeneous in the trench, resulting in void formation at one side of the trench wall during plating. Numerical analysis of the Cu electrolyte solution flow clarified that Cu ion transportation is lowered substantially by the generation of two vortices in the wire trench when the wire width is less than 50 nm. We proposed a method to enhance transportation of Cu ions by enlarging the open angle at the top edge of the trenches to prevent void formation. The effect of the method for void-free filling was predicted by the numerical analysis of the Cu electrolyte solution flow and confirmed by the actual filling experiment of Cu into the wire trench with 60 nm width. [doi:10.2320/matertrans.M2012069], JAPAN INST METALS
Materials Transactions, 2012, [Reviewed]

Substrate temperature dependence of electrical and structural properties of Ru films
Takatoshi Nagano; Kazuya Inokuchi; Kunihiro Tamahashi; Nobuhiro Ishikawa; Yasushi Sasajima; Jin Onuki, Microstructures and resistivities of sputtered Ru films were investigated as a function of substrate temperature to obtain a single-layered Ru barrier without a Ta/TaN under layer. High resistivity Ru films with a high density of crevices, which enhances Cu diffusion along the crevices, were formed by the conventional sputtering process, i.e., sputtering at room temperature and annealing at 400 degrees C-700 degrees C for 30 min in Ar + 3%H(2). But, crevice-free and smooth Ru films with low resistivity, the same as that for the bulk phase, were formed when substrate temperature add sputtering was raised to 700 degrees C. Ru films formed by this process had (002) preferred orientation and then Cu (111) was formed by plating. This result corresponded to the tendency predicted by ab initio calculations. (C) 2011 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
Thin Solid Films, 2011, [Reviewed]

Effect of additive-free plating and high heating rate annealing on the formation of low resistivity fine Cu wires
Jin Onuki; Kunihiro Tamahashi; Takashi Namekawa; Yasushi Sasajima, Last, Low resistivity Cu wires were developed by the combination of lessening impurities through additive-free plating and high heating rate annealing. Resistivities of Cu wires made with the new method were about 30% lower than those made by conventional plating with additives and annealing at the same temperature in H-2. Low resistivity Cu wires were realized even at temperatures 100 K lower than conventional annealing temperatures due to substantial grain growth by the high heating rate annealing in the Cu wires made with the additive-free plating. [doi:10.2320/matertrans.M2011098], JAPAN INST METALS
Materials Transactions, 2011, [Reviewed]

Effect of impurities on the grain growth of polycrystlline Cu thin film
Yasushi Sasajima; Takeshiro Nagai; Jin Onuki, Lead, We simulated grain growth of polycrystalline Cu thin film with impurities by the molecular dynamics method. The examined impurities were O and Ti of which the binding energy with Cu is strong and weak, respectively, and of which size is similar to matrix element Cu. The crystallinity and texture of the film were estimated by 2D-Fourier transformation of the atomic structure. The present study revealed that the impurity with strong binding energy and similar size to Cu atom segregated at the grain boundary and inhibited the grain growth. The obtained results showed good accordance with those obtained in actual experiments on Cu ultra-fine wires., ELECTROCHEMICAL SOC JAPAN
Electrochemistry, 2011, [Reviewed]

Impact of high heating rate, low temerature, and short time annealing on the realization of low resistibity Cu wire
Jin Onuki; Kunihiro Tamahashi; Takashi Namekawa; Yasushi Sasajima, Last, Low resistivity Cu wires were obtained by high heating rate short time and low temperature annealing even at a temperature 100 K lower and for a time 67% shorter than the conventional H-2 annealing temperature and time This was due to promotion of the grain growth by the release of grain boundary energy when the heating rate to the peak temperature was set at I 7 K/s Resistivity of Cu wilts made by the new process at 573 K w is lower than that of wires made by conventional H-2 annealing at 673 K for 30 min [doi 10 2320/matertrans M2010133], JAPAN INST METALS
Materials Transactions, 01 Sep. 2010, [Reviewed]

Reduction in resistivity of 50 nm wide Cu wire by high heating rate and short time annealing utilizing misorientation energy
Jin Onuki; Khoupin Khoo; Yasushi Sasajima; Yasunori Chonan; Takashi Kimura, The resistivities and microstructures for 50 nm Cu wires fabricated by high heating rate (3 K/s) and short time (1 min) annealing using infrared rapid thermal annealing equipment have been investigated as a function of annealing temperature and compared to those properties for wires fabricated by a slow heating rate (0.08 K/s), long time (30 min) conventional H(2) annealing process. The resistivity of wires annealed by the new process decreased substantially with increasing annealing temperature from 573 to 773 K. The resistivity had its lowest value between 773 and 873 K, and it increased rapidly with annealing temperature above 923 K. The average rho value was 2.98 mu Omega cm for 773 K new process wires, whereas average rho values were about 3.55 mu Omega cm for 573 K and 3.42 mu Omega cm for 673 K conventionally H(2) annealed wires. This resistivity value for the new process wires was about 16% lower than the value for wires annealed at 573 K and 13% lower than the value for the wires annealed at 673 K by the conventional H(2) annealing process. The substantial resistivity decrease in the new process Cu wires is mainly attributed to uniform grain size coarsening and high (111) orientation effects by the high temperature and high rate heating, while the resistivity increase at higher heating temperatures above 923 K for new process wires is mainly attributed to the reaction between Cu and Ta/TaN barriers; the greater the extent of the reaction, the higher the resistivity. (C) 2010 American Institute of Physics. [doi:10.1063/1.3474663], AMER INST PHYSICS
Journal of Applied Physics, 15 Aug. 2010, [Reviewed]

Molecular dynamics simulation of grain growth of Cu film - effects of adhesion strength between substrate and Cu atoms -
Takatoshi Kato; Takeshiro Nagai; Yasushi Sasajima; Jin Onuki, Corresponding, The growth process of Cu polycrystal films on Si, Ti, W and Ru substrate during isothermal annealing was studied by the molecular dynamics method. We focused on the influence of the adhesion strength between substrate and Cu on crystallinity and orientational order of the film. After structural relaxation at low temperature (50 K), the movements of individual Cu atoms were calculated for different annealing temperatures using the molecular dynamics method. The crystallinity and orientational order of the film were examined by 2D-Fourier transformation of the atomic structure. We found that the system with strong adhesion strength between substrate and Cu showed higher crystallinity and orientational order for (111) oriented Cu film. [doi:10.2320/matertrans.MG200903], JAPAN INST METALS
Material Transaction, Apr. 2010, [Reviewed]

Impact of High Heating Rate,Low Temperature and Short Time Annealing on the Realization of Low Resistivity Cu Wire
J. Onuki; K. Tamahashi; T. Namekawa; Y. Sasajima, Last, Low resistivity Cu wires were obtained by high heating rate short time and low temperature annealing even at a temperature 100 K lower and for a time 67% shorter than the conventional H-2 annealing temperature and time This was due to promotion of the grain growth by the release of grain boundary energy when the heating rate to the peak temperature was set at I 7 K/s Resistivity of Cu wilts made by the new process at 573 K w is lower than that of wires made by conventional H-2 annealing at 673 K for 30 min [doi 10 2320/matertrans M2010133], JAPAN INST METALS
Materials Transactions, 2010, [Reviewed]

Grain coarsening mechanism of Cu thin films by rapid annealing
Yasushi Sasajima; Junpei Kageyama; Khyoupin Khoo; Jin Onuki, Lead, Cu thin films have been produced by an electroplating method using nominal 9N anode and nominal 6N CuSO(4)center dot 5H(2)O electrolyte. Film samples were heat-treated by two procedures: conventional isothermal annealing in hydrogen atmosphere (abbreviated as H(2) annealing) and rapid thermal annealing with an infrared lamp (abbreviated as RTA). After heat treatment, the average grain diameters and the grain orientation distributions were examined by electron backscattering pattern analysis. The RTA samples (400 degrees C for 5 min) have a larger average grain diameter, more uniform grain distribution and higher ratio of (111) orientation than H(2) annealed samples (400 degrees C for 30 min). This means that RTA can produce films with coarser and more uniformly distributed grains than H(2) annealing within a short time, i.e. only a few minutes. To clarify the grain coarsening mechanism, grain growth by RTA was simulated using the phase field method. The simulated grain diameter reaches its maximum at a heating rate which is the same order as that in the actual RTA experiment. The maximum grain diameter is larger than that obtained by H(2) annealing with the same annealing time at the isothermal stage as in RTA. The distribution of the misorientation was analyzed which led to a proposed grain growth model for the RTA method. (C) 2010 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
Thin Solid Films, 2010, [Reviewed]

Reduction in resistivity of 50nm wide Cu wire by high heating rate and short time annealing utilizing misorientation energy
J. Onuki; K.P. Khoo; Y. Sasajima; Y. Chonan; T. Kimura, The resistivities and microstructures for 50 nm Cu wires fabricated by high heating rate (3 K/s) and short time (1 min) annealing using infrared rapid thermal annealing equipment have been investigated as a function of annealing temperature and compared to those properties for wires fabricated by a slow heating rate (0.08 K/s), long time (30 min) conventional H(2) annealing process. The resistivity of wires annealed by the new process decreased substantially with increasing annealing temperature from 573 to 773 K. The resistivity had its lowest value between 773 and 873 K, and it increased rapidly with annealing temperature above 923 K. The average rho value was 2.98 mu Omega cm for 773 K new process wires, whereas average rho values were about 3.55 mu Omega cm for 573 K and 3.42 mu Omega cm for 673 K conventionally H(2) annealed wires. This resistivity value for the new process wires was about 16% lower than the value for wires annealed at 573 K and 13% lower than the value for the wires annealed at 673 K by the conventional H(2) annealing process. The substantial resistivity decrease in the new process Cu wires is mainly attributed to uniform grain size coarsening and high (111) orientation effects by the high temperature and high rate heating, while the resistivity increase at higher heating temperatures above 923 K for new process wires is mainly attributed to the reaction between Cu and Ta/TaN barriers; the greater the extent of the reaction, the higher the resistivity. (C) 2010 American Institute of Physics. [doi:10.1063/1.3474663], AMER INST PHYSICS
J. Appl.Phys., 2010, [Reviewed]

Void generation during the annealing process of very narrow copper wires
Yasushi Sasajima; Tomoaki Akabane; Takeshiro Nagai; Yasunori Chonan and Jin Onuki, Lead, We carried out experiments on stress-induced void formation in ultrathin Cu wires while varying heat-treatment temperature, wire dimensions, and overlayer thickness. We also did molecular dynamics simulations of void formation in a buried wire of nanometer scale and compared these results with experimental results to clarify details of the void formation mechanism. The experimental and simulation results showed good accordance in explaining the effects of wire width, overlayer thickness, and cooling rate on void formation. (1) The narrower the wire width, the easier the void formation. (2) The thicker the overlayer, the easier the void formation. (3) The larger the cooling rate, the greater the suppression of void formation. From the obtained results, we constructed a void formation model for a buried wire. The basic concept of the model describes how local strain at four trench corners is relaxed in the buried wire in the annealing process. There are two ways to relax the local strain: (1) structural relaxation to strengthen adhesion between the wire and substrate and (2) reduction of the surface area to minimize surface energy. The way preferred is dependent on how parameters such as system temperature and wire dimensions are combined. Based on the void formation model, we interpreted the effects of wire strain, wire dimensions, and overlayer thickness. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3091291], AMER INST PHYSICS
Journal of Applied Physics, 2009, [Reviewed]

MD Simulation of Void Generation during Annealing Process of Copper Wiring
Takeshiro Nagai; Yasushi Sasajima and Jin Onuki, Corresponding, In the production of LSIs, annealing is necessary to coarsen the crystal grains in the wires. In this process, wiring breakdown is frequently caused by defect generation at the T-shaped buried wire. To overcome this difficulty, we investigated the conditions for defect generation and the atomic behavior during the annealing process by molecular dynamics simulation. We focused on the influence of the adhesion strength between substrate and wire materials on void generation. As samples for the simulation, a Cu single crystal was buried in three different substrates, Si, Ti, and W. After structural relaxation at low temperature (50 K), the movements of individual Cu atoms were simulated for different annealing temperatures using the molecular dynamics method. The strain of the buried wire was also varied where the thickness of the covered layer, the width and the height of the wire were fixed. We found that the system with strong adhesion strength between substrate and wire materials suppressed void generation. [doi:10.2320/matertrans.MRA2008477], JAPAN INST METALS
Material Transaction, 2009, [Reviewed]

Effects of Crystal Orientation on the Stability of Cu Ultra-Fine-Wire Structure
Takeshiro Nagai; Tomoaki Akabane; Yasushi Sasajima; Jin Onuki, Cu is now commonly used for wires in LSI because of high conductivity and EM resistance. However, voids are frequently produced at the bottom of the Cu wire during heat treatment process and wire breaking occurs. To clarify the origin of the defect production process at the atomistic level, we have performed molecular dynamics simulation. The focus of the present study is how the difference of crystal orientation affects on the stability of Cu ultra-fine-wire structure. Cu atoms with fcc structure were placed in the wire form surrounded by rigid Ti walls. Three different orientations of Cu wire were examined: (111) stacked on the bottom, on the side wall and parallel to the wiring direction. The isothermal annealing was at 300-900 K and the compression strain of the buried wire was 0-4%. It was found that the wire structure with (111) stacked parallel to the front of the drain is most unstable. Therefore the controlling crystal orientation is shown to be one of the key technologies for the next generation wiring process., JAPAN INST METALS
JOURNAL OF THE JAPAN INSTITUTE OF METALS, Sep. 2008, [Reviewed]

Phase field simulation of heat treatment process of Cu ultra fine wire
Junpei Kageyama; Yasushi Sasajima; Minoru Ichimura; Jin Onuki, Corresponding, We have simulated grain growth process of a Cu ultra fine wire by the phase field method. As the model of the calculation, we used the poly crystal model of Kobayashi-Warren in which the phase field and the orientation field are considered. The section of the fine wire was divided into 2-dimensional meshes and the time developing equations of the phase field and the orientation field were solved numerically. The isothermal annealing was simulated on the condition of the annealing temperature 523 -973 K and the annealing time 333 second, and the constant- rate annealing process was simulated on the condition of the first temperature at 373 K and the final temperature 673 -773 K with heating rate 0.45 -9.01 [K/s]. In order to clarify the effect of heating rate on the crystal structure, the post-isothermal annealing was performed in the simulation to make the thermal energy supplied to the sample equal among the various annealing processes. The change of the crystal grain radius was investigated by varying the heating rate. It was found that the crystal grain radius obtained by a certain range of the heating rate 1.29 -9.01 [K/s] is larger than that obtained by the isothermal annealing., MATERIALS RESEARCH SOCIETY JAPAN-MRS-J
Trans. MRS-J, 2008, [Reviewed]

MD Simulation of Defect Generation during Annealing Process of Copper Wiring
Tomoaki Akabane; Yasushi Sasajima; Jin Onuki, Corresponding, In the production of LSI, annealing process is necessary to coarsen the crystal grains in the wire. In this process, the wiring breakdown is frequently caused by the defect generation in the bottom of the buried wire. To overcome this difficulty, we investigated the conditions for the defect generation and the atomic behavior during the annealing process by the molecular dynamics simulation. Three rigid plates are placed as the two sidewalls and the bottom of the wire with a rectangular parallelepiped shape. A single crystalline copper is placed as the material of the wiring and the covered layer. After the relaxation at a low temperature for the structural stabilization, an annealing temperature is set for the sample. Calculation parameters are the annealing temperature, the thickness of the covered layer, the width, the height and the strain of the wire. It was shown that defect generations are suppressed when the annealing temperature is lower, the dimension of the wire is larger and the compressive strain is larger. These results coincide with the tendency of the real experiments., MATERIALS RESEARCH SOCIETY JAPAN-MRS-J
Trans. MRS-J, 2008, [Reviewed]

Cu超微細配線構造の安定性に及ぼす結晶方位の影響　　　　　　　　　　　　　　　
永井 傑朗; 赤羽 智明; 篠嶋 妥; 大貫 仁, Corresponding
日本金属学会誌, 2008, [Reviewed]

Coatings Adhesion Evaluation by Nanoscratching Simulation Using the Molecular Dynamics Method
Tomoaki Akabane; Yasushi Sasajima and Jin Onuki, Corresponding, By using a molecular dynamics method, a computer simulation of a scratch test on bilayer thin films on a nanometer scale has been performed. In the present simulation, the substrate and thin-film material are TiN or SiO2 and Al or Cu, respectively. The indentor is assumed to be a perfect rigid body, and the Morse potential is utilized as the interaction between the indentor and a specimen atom. The extended Tersoff potential is assumed as the interaction between specimen atoms. Results indicate that the standard deviation of the friction constant becomes maximum when the scratching load is critical to spalling. The critical loads obtained by the present simulation and actual experiments do not match quantitatively. In contrast, the maximum standard deviation reproduces the spalling strength evaluated from actual experiments. On the basis of this finding, a new evaluation technique for adhesion strength using a nanoscratching test is proposed., INST PURE APPLIED PHYSICS
Japanese Journal of Applied Physics, 2007, [Reviewed]

Nanoscratching of metallic thin films on silicon substrate: a molecular dynamics study
Tomoaki Akabane; Yasushi Sasajima and Jin Onuki, Corresponding, By using a molecular dynamics method, a computer simulation of a scratch test on a nanometer scale has been performed. The specimen is composed of four atomic layers of metallic atoms deposited on a substrate of 864 silicon atoms. The thin-film materials chosen were Al, Cu, Ti, and W. The critical load had a similar tendency to the interface energy of a heterogeneous junction, and the maximum friction constant coincided fairly well with adhesion strength. On the basis of our simulation results we propose methods for detecting the critical load of scratching and for estimating the bonding of the film-substrate interface., MINERALS METALS MATERIALS SOC
Journal of Electronic Materials, 2007, [Reviewed]

Determination of the Phase-Field Parameters for ComputerSimulation of Heat Treatment Process of Ultra Thin Al Film
Junpei Kageyama1; Yasushi Sasajima; Minoru Ichimura and Jin Onuki, Corresponding, We have simulated grain growth process of an Al ultra thin film by the phase field method. As the model of the calculation, we used the poly crystal model of Kobayashi-Warren in which the phase field and the orientation field are considered. The section of the thin film was divided into 2-dimensional meshes and the time developing equations of the phase field and the orientation field were solved numerically. The parameters for the present calculation have been determined to fit to the results of the grain growth experiment of Al thin film. The relaxation time of grain rotation, only the phase field parameter assumed to be temperature dependent, was determined from the time evolution of averaged grain size in the annealed Al thin film. Isothermal annealing process at various temperatures has been examined using the tuned phase field parameters and the temperature dependence of grain growth was clearly observed., JAPAN INST METALS
Materials Transactions, 2007, [Reviewed]

シリコンナノ結晶の凝集過程と構造安定性：分子動力学シミュレーション
篠嶋 妥; 赤羽 智明, Lead, 分子動力学法を用いて、シリコンナノ結晶の凝集過程を計算機でシミュレートし、その構造安定性について検討した。平衡状態に達した後の構造について動径分布関数を解析して、シリコンナノ結晶の安定領域を決定した。, 日本金属学会
日本金属学会誌, 2007, [Reviewed]

Computer simulation of high-energy-beam irradiation of single crystalline silicon
Yasushi Sasajima; Tomoaki Akabane; Tetsuya Nakazawa; Akihiro Iwase, Lead, The structural relaxation caused by the high-energy-beam irradiation of single-crystalline silicon was simulated by the molecular dynamics method. As the initial condition, high thermal energy was supplied to the individual silicon atoms within a cylindrical region of nanometer-order radius located in the center of the specimen. The Tersoff potential was assumed as the interaction mechanism between silicon atoms. The supplied thermal energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps; then it diffused in the specimen by an ordinary thermal dissipation process. The amorphized track radius R(a) was determined as a function of the energy density of the thermalized region. It was found that the relationship between R(a) and the effective stopping power gS(e) follows the relation R(a)(2) = a log(gS(e)) + b, which is similar to the formula derived on the basis of the thermal spike model [G. Szenes, J. Nuel. Mater. 336 (2005) 81]. It was also found that the mechanism of structural transition changes at the thermalized region of 1 nm radius. (c) 2007 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Nucl. Instr. and Meth. in Phys. Res. B, 2007, [Reviewed]

Computer simulation of silicon nanoscratch test
Tomoaki Akabane; Yasushi Sasajima; Jin Onuki, Corresponding, By the molecular dynamics method, a computer simulation of a scratch test with a nanometer scale was performed. The specimen was composed of 1008 silicon atoms with a diamond single-crystal structure. The indentor was assumed to be a perfect rigid body, and the Morse potential was utilized as the interaction between the indentor and a silicon atom. Two types of potential, i.e., Stillinger-Weber and Tersoff potentials. were examined as the interaction between silicon atoms. The present simulation clarified that the standard deviation of the friction constant increased with decreasing scratch depth and became maximum when the indentor just began to scratch the specimen surface at critical load. The friction coefficient. indentation hardness and scratch hardness at critical load were estimated to be 1.2-1.6, 80-90GPa and 8.59AGPa, respectively., JAPAN INST METALS
Materials Transactions, 2006, [Reviewed]

フェーズフィールド法によるＡｌ-Ｚｎ合金のデンドライト成長シミュレーション
篠嶋 妥; 市村 稔, Lead, フェーズフィールド法を用いてAl‐Zn二元合金の一方向凝固過程におけるデンドライト成長のシミュレーションを行った。Znの濃度場およびフェーズフィールドの時間変化を計算し，これにより結晶成長形態に及ぼす凝固速度や温度勾配の影響を調べた。, The Japan Institute of Light Metals
軽金属, 2005, [Reviewed]

サクシノニトリル－アセトン系有機モデル合金のデンドライト成長　　　　　　　　　　　　　　　
篠嶋 妥; 市村 稔, Lead, 二元系合金の凝固過程を解明するために、透明有機化合物としてサクシノニトリル（SCN）－アセトンをモデル合金系とし、一方向凝固法を用いて結晶がデンドライト成長する様子をその場観察した。デンドライトの１次枝間隔（DAS1）と２次枝間隔(DAS2)の、結晶の成長速度に対する関係について調べた。
日本金属学会誌, 2005, [Reviewed]

Phase field simulation on directional solidification of succinonitrile(SCN)-Aceton organic model alloy
Junpei Kgeyama; Yasushi Sasajima; Minoru Ichimura, Corresponding, Phase field simulation on directional solidification of succinonitrile (SCN)-acetone organic model alloy was performed. The development of concentration and phase field profile was calculated in order to clarify the dependences of growth velocity V and temperature gradient G on the morphology of growing crystal.
Concerning the primary dendrite arm spacing, lambda(1), the relationship between lambda(4)(1)G(2) V/k Delta T-0 and V was examined, where k and Delta T-0 are partition coefficient and temperature difference between liquid and solid phases, respectively. The calculated values of lambda(4)(1)G(2) V/k Delta T-0 did not show a universal relationship but the trends of the present calculation can be understood by extrapolation from experimental data. The power law index of V for the lambda(4)(1)G(2) V/k Delta T-0-V plot took similar values between the experiments and the present calculation for some cases. The lambda(1)-V relationship did not show dependences on temperature of the low temperature side and nor acetone concentration. For the curvature radius R, the R-V relationship can be fitted by a simple function regardless the value of G.
In addition, the calculated values of R and the power low indexes of V for R were compared to the dendrite growth theory and good accordance was confirmed., JAPAN INST METALS
Materials Transactions, 2005, [Reviewed]

シリコンのナノインデンテーションの計算機実験　　　　　　　　　　　　　　　
赤羽 智明; 篠嶋 妥, Corresponding, シリコンのナノインデンテーションの計算機実験を行った。シリコンの相互作用ポテンシャルとしてスティリンジャ・ウェーバー型を仮定し、円錐形の剛体圧子をシリコン単結晶に一定荷重で押し込んだ。荷重－押し込み深さ曲線を取り、最大押し込み深さから硬さを評価した。
日本金属学会誌, 2005

フェーズフィールド法によるＡｌ－Ｚｎ合金の一方向凝固シミュレーション
篠嶋 妥; 市村 稔, Lead, フェーズフィールド法を用いたAl-Zn二元合金の一方向凝固シミュレーションを行った。結果を視覚化し、Znの濃度 、温度勾配G、成長速度Vの結晶成長形態及び平滑界面の安定性に対する影響を調べた。, 軽金属学会
軽金属, 2004

フェーズフィールド法による凝固シミュレーション
篠嶋 妥, Lead, 軽金属学会
軽金属, 2004, [Reviewed]

Ａｌ－ＣｕおよびＡｌ－Ｚｎ合金のデンドライト成長機構とフェーズフィールド法シミュレーション　　　　　　　　　　　　　　　
篠嶋 妥; 市村 稔, Lead
軽金属, 2003

多層薄膜の熱伝導：分子動力学による研究　　　　　　　　　　　　　　　
篠嶋 妥; 深谷 太雄, Lead
熱物性, 2002

フェーズフィールド法によるＡｌ－Ｃｕ二元合金の等温デンドライト成長シミュレーション
篠嶋 妥; 市村 稔, Lead, The isothermal dendritic growth process of an Al–Cu binary alloy was simulated by utilizing the phase-field method. The morphology forming process of the α phase of the aluminum rich Al–Cu system was clarified dynamically. Lower the growth temperature, faster the growth velocity of the dendrite primary arm and finer the dendrite structure. In addition, it was confirmed that the degree of segregation of Cu in dendrite arms became evident in increasing supercooling. The growth velocity of primary dendrite arm V can be expressed as a function of dimensionless supercooling Δ and Cu atomic concentration c such that V [× 10⁵ μm/s] = (1160–124c)Δ^2.45. The radius of the dendrite primary arm d does not depend on Cu atomic concentration c but on dimensionless supercooling Δ as d[μm]=0.0818Δ^−0.543. Dimensionless supersaturation Δ_c is a function of Peclet number P= (Vd/2D_L) such that Δ_c = 0.929 + 1.2002 (1⁄P)² -1.4128 (1⁄P)., The Japan Institute of Light Metals
軽金属, 2002

Molecular dynamics study of cluster deposition in thermal plasma flash evaporation
N Yamaguchi; Y Sasajima; K Terashima; T Yoshida, Corresponding, We simulated the rearrangement process of a high-temperature cluster put on a low-temperature substrate using molecular dynamics to verify the rearrangement behavior of the hot clusters. In the first step, a monoatomic homogeneous system wets simulated. A spherical fee stacked cluster consisting of 418 atoms corresponding to a 2 nm cluster, was placed on the 6 planes of a fee ( 1 1 1) substrate. The interaction potential was assumed to be the Morse function corresponding to a material with a melting point of 1680 K. The substrate temperature T-sub and the initial cluster temperature T-cluster(init) were varied from 300 to 1000 K and from 1450 to 3000 K, respectively. In the case of T-cluster(init) < 2100 K, the degree of cluster rearrangement is slight. Even at T-sub = 1000 K, the final structure was a six atomic-layer-high cap-like structure. On the other hand, clusters with T-cluster(init) > 2400 K rearranged markedly into almost two-dimensional clusters even at T-sub = 300 It and the degree of rearrangement seemed to be independent of the substrate temperature. It was revealed that high temperature nanoscale clusters could deform easily even on a room-temperature substrate owing to their high internal energy. This was confirmed by scanning tunneling microscopy, (C) 1999 Published by Elsevier Science Ltd. All rights reserved., ELSEVIER SCIENCE SA
Thin Solid Films, 1999

Monte Carlo simulation of hydrogen diffusivity in aluminum with anisotropic grain boundaries
M Ichimura; Y Sasajima, Corresponding, The hydrogen diffusivity in polycrystalline aluminum is simulated by the Monte Carlo method based on the random walk theory. We have previously performed a simulation of hydrogen diffusivity in aluminum with isotropic grain boundaries, known as the grain boundary cross (GBC) effect. In this study, a similar diffusivity simulation of a sample with anisotropic grain boundaries is pel formed. The anisotropy of grains corresponds well with the columnar grains in the real specimens for which the diffusivity peak was measured. For samples with anisotropic grain-shapes, the hydrogen diffusivity is enhanced along the longer side of grain boundaries for larger grains, and is increasingly suppressed by trapping at grain boundary junctions for smaller grains. This results in a complicated or disordered peak at some intermediate grain sizes. This is termed the grain boundary anisotropic (GBA) effect. An examination of these simulation results supports and confirms the anisotropic qualities of the GBC effect previously determined experimentally by us., JAPAN SOC APPLIED PHYSICS
Jpn. J. Appl. Phys, 1998

Computer Simulation of Growth Process of Binary Quasi Crystal
Yasushi Sasajima; Katsumi Adachi; Hideki Tanaka; Minoru Ichimura; Masanori Itaba; Satoru Ozawa, We performed Monte Carlo simulation of the aggregation process of a two-component Lennard-Jones system on the two-dimensional (2D) Penrose lattice for the purpose of studying the details of the creation and growth process of quasi crystals. We adopted the potential parameter values proposed by Widom et al. [Phys. Rev. Lett. 58 (1987) 706]. The present simulation clarified that the stability of the formed quasi crystals depends on temperature and the strength of the potential and that the transition from solid state to liquid state occurs when the value of the inverse of the dimensionless temperature is approximately 4.0. © The Japan Society of Applied Physics.
Japanese Journal of Applied Physics, 1994

Computer Simulation of Film Growth Process on the Two-Dimensional Penrose Pattern
Sasajima Yasushi; Tanaka Hideki; Ichimura Minoru; Itaba Masanori; Ozawa Satoru, We performed computer simulation of the film growth process on the two-dimensional (2D) Penrose pattern, which is considered a typical structural model of quasicrystal. The atomistic structure of the deposited atoms was calculated as a function of time under various conditions of atomic binding energy, temperature and deposition rate. The Monte Carlo method based upon the solid-on-solid model was utilized for the present calculation. We found a geometrical restriction on the growth front of grains in the 2D Penrose pattern, which is also expected for the growth of an actual quasicrystal., The Japan Society of Applied Physics
Japanese Journal of Applied Physics, 1993, [Reviewed]

高速重イオン照射したSiO₂におけるナノ構造形成メカニズム
石川法人; 田口富嗣; 小河浩晃; 篠嶋妥
日本金属学会講演大会(Web), 2025

水素プラズマによるLIB正極からのレアメタルの乾式還元
吉宗大和; 永野隆敏; 篠嶋妥; 大貫仁; 大橋健也; 吉田武彦
日本金属学会講演大会(Web), 2024

水素雰囲気中で炭素粉末を用いたLIB正極からのレアメタルの乾式還元
永野隆敏; 吉宗大和; 篠嶋妥; 大貫仁; 大橋健也; 吉田武彦
日本金属学会講演大会(Web), 2024

TSV (Through Silicon Via) with Thoroughly Suppressed Plastic Deformation During Heat Treatment
篠嶋妥; ZARE Yazdan; 大貫仁
化学工業, 22 Jan. 2021
Lead

フェーズフィールド法によるSi-Al系の界面形状制御シミュレーション
岩田恭平; 湯地隆介; 遠藤基史; 篠嶋妥; 大貫仁
日本金属学会講演概要(CD-ROM), 2019

Si-Al二元系におけるSi固相成長における界面安定性の計算機実験
岩田恭平; 湯地隆介; 遠藤基史; 篠嶋妥; 大貫仁
軽金属学会大会講演概要, 2019

計算機実験によるロータスアルミニウムにおけるポア成長の最適条件探索
飯塚恒太; 湯地隆介; 遠藤基史; 池田輝之; 篠嶋妥
軽金属学会大会講演概要, 2019

Cosmic ray capability of power semiconductor devices
織田哲男; 新井大夏; 小口裕之; 河野大樹; 松本達也; 濱田寛哉; 木下昴洋; 篠嶋妥
量子ビームサイエンスフェスタ(Web), 2018

Phase field simulation of pore growth in lotus aluminum
Bin Liu; Teruyuki Ikeda; Yasushi Sasajima
Keikinzoku/Journal of Japan Institute of Light Metals, 2018

銅極細配線における粒成長を阻害する不純物効果のフェーズフィールドシミュレーション
篠嶋妥; 大貫仁
日本金属学会講演概要(CD-ROM), 2017

添加剤低減と超高純度めっき液を利用した大粒径化配線プロセス
宮本諒; 篠嶋妥; 稲見隆; 玉橋邦裕; 滑川孝; 大貫仁
日本金属学会講演概要(CD-ROM), 2017

Mg₂Si合金におけるSi析出相の成長過程のPhase-Fieldシミュレーション
劉濱; 池田輝之; 篠嶋妥
日本金属学会講演概要(CD-ROM), 2016

熱的照射によるAl-Cu合金の析出過程のPhase-Fieldシミュレーション
劉濱; 篠嶋妥; 岩瀬彰宏
日本金属学会講演概要(CD-ROM), 2015

微細Cu配線における粒界偏析元素の直接観察と第一原理計算
永野隆敏; 圓谷哲紀; 江口大貴; 玉橋邦裕; 篠嶋妥; 大貫仁; 石川信博
日本金属学会講演概要(CD-ROM), 2012

微細Cu配線のナノ構造に及ぼす加熱速度の影響
白石悠; 柯一青; 玉橋邦裕; 滑川孝; 篠嶋妥; 大貫仁
日本金属学会講演概要(CD-ROM), 2012

高速繰り返し加熱処理で作製したCu配線材料の結晶ナノ構造評価
横山貴大; 荒山卓也; 玉橋邦裕; 滑川孝; 篠嶋妥; 大貫仁
日本金属学会講演概要(CD-ROM), 2012

30a-D-3 Computer Simulation of Film Growth on the 2D penrose pattern
Sasajima Y.; T Hideki.; Adachi K.; Ichimura M.; Itaba M.; Ozawa S.
Meeting Abstracts of the Physical Society of Japan, 1993

〔Major achievements〕半導体デバイスにおける界面成語技術：固体界面物性と計算機実験の基礎と応用　　　　　　　　　　　　　　　
大貫 仁・篠嶋 妥・永野 隆敏・稲見 隆, Joint work
内田老鶴圃, 20 Apr. 2021
9784753650507

茨城大学工学基礎ミニマム「物理」　　　　　　　　　　　　　　　
第; 著者, Joint work
学術図書出版, 31 Mar. 2002

コンピュータによるシリコンテクノロジーＩ　　　　　　　　　　　　　　　
山本良一編; 篠嶋 妥, Joint work
海文堂, Apr. 1990

Molecular Dynamics Simulation of high-energy beam irradiation of SiO2 crystal with free surface　　　　　　　　　　　　　　　
Yasushi Sasajima; Satoshi Kimata; Norito Ishikawa
21st International Conference on Radiation Effects in Insulators （REI-21）, 05 Sep. 2023
20230903, 20230908

Elimination of Plastic Deformation of Copper in Cu-TSV Using Triple-lining Method　　　　　　　　　　　　　　　
Yazdan Zare; Yasushi Sasajima; Jin Ohnuki
4th International Symposium of Quantum Beam Science at,Ibaraki University, 31 Oct. 2019
20191031, 20191101

計算機実験によるロータスアルミニウムにおける,ポア成長の最適条件探索　　　　　　　　　　　　　　　
飯塚 恒太; 湯地 隆介; 遠藤 基史; 池田 輝之; 篠嶋 妥
軽金属学会, 11 May 2019
20190510, 20190512

Si-Al二元系におけるSi固相成長における界面安定性の計算機実験　　　　　　　　　　　　　　　
岩田恭平; 湯地隆介; 遠藤基史; 篠嶋妥; 大貫仁
軽金属学会, 11 May 2019
20190510, 20190512

計算機実験によるロータスアルミニウムにおける ポア成長の最適条件探索　　　　　　　　　　　　　　　
飯塚 恒太; 湯地 隆介; 遠藤 基史; 池田 輝之; 篠嶋 妥
軽金属学会, 11 May 2019

ロータスアルミニウムにおけるポア成長のフェーズフィールドシミュレーション　　　　　　　　　　　　　　　
飯塚 恒太; 湯地 隆介; 遠藤 基史; 篠嶋 妥; 池田 輝之
日本金属学会, 20 Mar. 2019

Si-Al二元系におけるSi固相成長のフェーズフィールドシミュレーション　　　　　　　　　　　　　　　
岩田 恭平; 湯地 隆介; 遠藤 基史; 篠嶋 妥; 大貫 仁
日本金属学会, 20 Mar. 2019

Grain Coarsening Mechanism of Cu Confined in Ultra-fine Wire　　　　　　　　　　　　　　　
Yasushi Sasajima; Takatoshi Nagano and Jin Onuki
WCSM-2018 (BIT’s 4th Annual World Congress of SmartMaterials -2018), 06 Mar. 2018

Pinning effect of Fe(ClO) compounds on Cu grain growth in very narrow Cu wires : ab initio calculation and Cs-corrected STEM observation　　　　　　　　　　　　　　　
Daiki Eguchi; Takatoshi Nagano; Nobuhiro Ishikawa; Kunihiro Tamahashi; Kishio Hidaka; Yasushi Sasajima; Jin Onuki
第23回日本MRS年会, 09 Dec. 2013, 日本MRS

Gd2O3添加CeO2への高速粒子線照射に関する分子動力学シミュレーション　　　　　　　　　　　　　　　
茨城大工; 長田 卓也; 安島直紀; 篠嶋 妥; 原研 石川; 法人; 大阪府大工; 岩瀬 彰宏
日本金属学会2012秋季大会シンポジウム, Sep. 2012

薄膜の粒成長に及ぼす基板の影響　　　　　　　　　　　　　　　
茨城大工; 圓谷 哲紀; 木村 勇貴; 永野 隆敏; 篠嶋 妥; 大貫 仁
日本金属学会2012秋季大会, Sep. 2012

超微細配線中のCu粒成長に及ぼす不純物元素の影響　　　　　　　　　　　　　　　
茨城大工; 江口 大貴; 圓谷 哲紀; 篠嶋 妥; 永野 隆敏; 大貫 仁
日本金属学会2012秋季大会, Sep. 2012

単結晶への高速粒子線照射の分子動力学シミュレーション　　　　　　　　　　　　　　　
茨城大工; 安島 直紀; 長田 卓也; 篠嶋 妥; 原研; 石川; 法人; 大阪府大工; 岩瀬 彰宏
日本金属学会2012秋季大会, Sep. 2012

アモルファスSi/Ge積層薄膜における析出過程の計算機実験　　　　　　　　　　　　　　　
茨城大工; 村上 純也; 長田 卓也; 篠嶋 妥
日本金属学会2012秋季大会, Sep. 2012

UO２の高エネルギービーム照射に関するシミュレーション実験　　　　　　　　　　　　　　　
茨城大工; 長田卓也; 小貫英昭; 工 篠嶋 妥; 原研 石川法人; 大阪府大工; 岩瀬彰宏
日本金属学会2011秋季大会, Nov. 2011

Cu 薄膜の粒成長に及ぼす基板の影響　　　　　　　　　　　　　　　
茨城大工; 木村勇貴; 工; 篠嶋; 妥; 大貫 仁
日本金属学会2011秋季大会, Nov. 2011

Cu 中の不純物の親和性の第一原理計算による評価　　　　　　　　　　　　　　　
茨城大工; 圓谷哲紀; 工; 篠嶋; 妥; 大貫; 仁; 永野隆敏
日本金属学会2011秋季大会, Nov. 2011

SiO2 の高エネルギービーム照射によるトラック形成シミュレーション　　　　　　　　　　　　　　　
茨城大工; 小貫英昭; 工; 篠嶋 妥; 大阪府大工; 岩瀬彰宏
日本金属学会2011秋季大会, Nov. 2011

UO2の高エネルギー・ビーム照射によるトラック形成の解析　　　　　　　　　　　　　　　
日本金属学会2011年春季大会, Mar. 2011

Characteristics of Ruthenium as barrier materials for Copper wires and search for its substitute materials　　　　　　　　　　　　　　　
第20回日本MRS学術シンポジウム, Dec. 2010

Computer simulation of high-enerugy-beam irradiation of single-crystalline silicon and β-cristobalite　　　　　　　　　　　　　　　
第20回日本MRS学術シンポジウム, Dec. 2010

Effects of Impurities on the Grain Growth of Aluminium Film　　　　　　　　　　　　　　　
ICAA12, Yokohama, Sep. 2010

Cu配線用バリアメタル材料としてのRuの特性と代替材料探索　　　　　　　　　　　　　　　
日本金属学会2010年秋季大会, Sep. 2010

SiO2の高エネルギービーム照射によるトラック形成の解析　　　　　　　　　　　　　　　
日本金属学会2010年秋季大会, Sep. 2010

Ａｌ系二元合金の等温デンドライト成長：フェーズフィールド法と摂動理論との比較　　　　　　　　　　　　　　　
軽金属学会第103回秋季大会講演, Nov. 2002

2010, 日本MRS

日本金属学会

軽金属学会

電動車輛駆動用電池リサイクル技術の開発【令和4年度からの継続事業】　　　　　　　　　　　　　　　
Jun. 2023 - Mar. 2024

電動車輛駆動用電池リサイクル技術の開発　　　　　　　　　　　　　　　
Aug. 2022 - Mar. 2023

Clarification of Radiation Damage Mechanism by Surface Nanostructure Observation of Radiation-Resistant Ceramics
Grant-in-Aid for Scientific Research (C)
Japan Atomic Energy Agency
Apr. 2020 - Mar. 2023

超音波接合における表面-界面遷移過程の動的直視　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research (C)
Apr. 2018 - Mar. 2021

立体的熱界面制御と新しい高効率熱電変換システム
Grant-in-Aid for Scientific Research (B)
Ibaraki University
Apr. 2017 - Mar. 2020

Direct observation of surface nanostructure created by swift heavy ions　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research (C)
01 Apr. 2016 - 01 Mar. 2019

Development of crystal-grain enlarging process for ultra-fine Cu wiring by strain-energy driving
Grant-in-Aid for Scientific Research (C)
Ibaraki University
Apr. 2016 - Mar. 2019

Direct observation of surface nanostructure created by swift heavy ions
Grant-in-Aid for Scientific Research (C)
Japan Atomic Energy Agency
Apr. 2016 - Mar. 2019

低次元制御量子ナノ構造をもつバルク熱電材料の創製　　　　　　　　　　　　　　　
挑戦的萌芽
Apr. 2016 - Mar. 2018

歪エネルギー駆動による超微細Cu配線の結晶粒粗大化プロセス開発　　　　　　　　　　　　　　　
基盤研究C
Apr. 2016 - Mar. 2018

高エネルギー非平衡状態を利用した熱電材料のナノ構造化と新機能　　　　　　　　　　　　　　　
基盤研究B
Apr. 2014 - Mar. 2017

Nano-structure Control of Cu Interconnects by a Very High Purity Plating Processes and Its Application to Next-generation LSIs.
Grant-in-Aid for Scientific Research (S)
Ibaraki University
2008 - 2012

Development of Cu Interconnects for 20nm Technology Node LSI
Grant-in-Aid for Scientific Research (A)
Ibaraki University
2005 - 2007

Measurement of thermal diffusivity of super lattice film by pico second pulse laser with variable wave length.
Grant-in-Aid for Scientific Research (C)
IBARAKI UNIVERSITY
1997 - 1998

The Diffusion Process of Hydrogen in the Quasi-Periodic Structure
Grant-in-Aid for General Scientific Research ©
Ibaraki University
1988 - 1990

金属超格子における超弾性効果の研究　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research on Priority Areas
Ibaraki University