| Project/Area Number |
09650813
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Metal making engineering
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
KAKIMOTO Koichi Institute of Advanced Material Study, Kyushu University, Associate Professor, 機能物質科学研究所, 助教授 (90291509)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OZOE Hiroyuki Institute of Advanced Material Study, Kyushu University, Professor, 機能物質科学研究所, 教授 (10033242)
|
|---|
| Project Period (FY) |
1997 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Keywords | MOLECULAR DYNAMICS / POINT DEFECTS / IMPURITY / SEMICONDUCTOR / ELECTRONIC DEVICES / DIFFUSION / PRESSURE / MIGRATION / シリコン / 酸素 / 拡散係数 |
|---|
| Research Abstract |
Molecular dynamics simulation was carried out to estimate diffusion constants and mechanism of point defects such as a single vacancy and a self-interstitial atom under hydrostatic pressure. Stillinger-Weber potential was used as a model potential, which is widely accepted for modeling of silicon crystals and melts. We obtained the following results on a self-interstitial atom from the calculation. 1) Diffusion constants of self-interstitial are almost independent of pressure within a range from -50 to +50 k bar. 2) A self-interstitial atom diffuses with a formation of dumbbell structure, which is aligned in [110] direction. For single vacancy, the following were clarified. 1) Diffusion constants of vacancy are also independent of pressure within a range from -40 to +40 k bar. 2) A vacancy diffuses with a switching mechanism to nearest neighbor lattice site.
Molecular dynamic simulation of an oxygen atom in silicon crystal and the melt was also carried out to obtain diffusion constants of oxygen in the melt. The simulation using mixed potential in the melt in which an oxygen atom and 216 silicon atoms were taken into account has been carried out. Vibration frequencies of oxygen and vacancy-oxygen (V-O) pair in the crystal have been calculated. Calculated frequency of oxygen and V-O pair were 1000 and 800 cmィイD1-1ィエD1, respectively, while experimental results which were obtained from Fourier transform spectra of infrared absorption (FTIR) are 1100 and 830 cmィイD1-1ィエD1, respectively. Oxygen diffusion constant was obtained in elevated temperature of 1700 K. Calculated diffusion constant of oxygen in the melt was 2x10ィイD1-4ィエD1 cmィイD12ィエD1/sec.
|
