Development of Virtual Experiment System for Growth Process of Functional Crystals

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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.