Development of Virtual Experiment System for Growth Process of Functional Crystals

以下是本研究的结果。(1)我们开发了一个计算晶体生长过程中位错密度的轴对称程序。用该程序对Si、GaAs和InP等半导体单晶进行了位错密度分析。(2)我们开发了一个计算晶体生长过程中位错密度的轴对称程序，该程序近似地考虑了晶体弹性常数和特定滑移方向的各向异性。也就是说，晶体各向异性沿方位角方向沿着平均。这种近似使得能够进行轴对称有限元建模。用该程序计算了GaAs和InP单晶的位错密度随生长方向的变化规律。(3)我们开发了一个计算晶体生长过程中位错密度的三维计算机程序的原型版本，在该程序中，晶体的各向异性被精确地考虑。(4)我们开发了一个计算铸锭退火过程中位错密度的轴对称计算机程序。用该程序对GaAs单晶锭进行了位错密度分析。(5)我们开发了一个原型版本的三维计算机程序的位错密度评估在铸锭退火过程中，其中的晶体各向异性是完全考虑。(6)我们开发的计算机程序，可应用于各种单晶的热应力分析。这些计算机代码被集成到一个热应力分析系统的生长块体单晶，连同一个前，后处理器。

The following are results of the present research.(1) We developed an axisymmetric computer code for dislocation density evaluation during crystal growth process, in which a bulk single crystal is assumed to be isotropic. Dislocation density analyses were performed for semiconductor single crystals such as Si, GaAs and InP by using this computer code.(2) We developed an axisymmetric computer code for dislocation density evaluation during crystal growth process, in which crystal anisotropy in elastic constants and specific slip directions are approximately considered. That is, the crystal anisotropy is averaged along the azimuthal direction. Such approximation enables axisymmetric finite element modeling. The effect of growth direction on the dislocation density was made clear for GaAs and InP single crystals by using this computer code.(3) We developed a prototype version of a three-dimensional computer code for dislocation density evaluation during crystal growth process, in which the crystal anisotropy is exactly taken into account.(4) We developed an axisymmetric computer code for dislocation density evaluation during ingot annealing process, in which a bulk single crystal is assumed to be isotropic. Dislocation density analyses were performed for a GaAs ingot by using this computer code.(5) We developed a prototype version of a three-dimensional computer code for dislocation density evaluation during ingot annealing process, in which the crystal anisotropy is exactly taken into account.(6) We developed computer codes that can be applied to thermal stress analyses for various kinds of single crystals. These computer codes were integrated into a thermal stress analysis system for the growth of a bulk single crystal, together with a pre- and post-processor.