STUDY ON DEFECT FORMATION IN BULK CRYSTAL FOR ELECTRONIC DEVICES

分子动力学模拟被用来估计的扩散常数和点变形的机制，如一种单一的真空和一种在液压压力下的自内部原子。Stillinger-Weber潜力被用作模型潜力，但在很大程度上被接受用于硅晶体和金属的建模。我们在计算中发现了以下的结果：自国际原子。（1）自内部扩散常数在-50到+50千巴的范围内几乎是独立的。（2）一种自间原子差异与哑铃结构的形成有关，在[110]方向上对齐。因为是单身，所以下面的事情是明确的。（1）真空的扩散常数在-40至+40千巴的范围内也是独立的。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。该模拟使用混合潜力在熔化的氧气原子和216硅原子被输入到帐户已经被携带出来。氧气和真空氧（V-O）对的振动频率在晶体中已经计算。Oxygen and V-O pair were 1000 and 800 cm D1-1 D1， respectively， while experimental results which were obtained from Fourier transform spectra of infrared absorption （FTIR） are 1100 and 830 cm D1-1 D1， respectively。氧气扩散常数在1700 K的升高温度下被发现。在melt was 2 x10中D1-4中D1 cm中D12中D1/sec。

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.