Study on Crystal Breakage Mechanism in Bulk InxGa1-xAs Grown by Two-Step MCZM Method

An analytical study has been carried out for understanding the breakage mechanism in bulk In_xGa_1- xAs crystal grown by the two-step multi-component zone melting (MCZM) method. It was confirmed from Raman scattering and energy dispersive X-ray experiments that large amount of strain was induced by the compositional variation in bulk In_xGa_1-xAs. It was anticipated that this large amount of strain could be the main cause of the cracks observed on the cut surface of the In_xGa_1- xAs crystal. In order to understand the crystal breakage mechanism clearly, the quantitative amount of strains and their distributions were evaluated using an axially symmetrical strain model for the existing-like compositional profile. It was found that the strains were increased gradually during the first step and then decreased drastically at the end of this step. This drastic changing behavior of strains could be the main cause of the breakage in the bulk In_xGa_{1 - x}As crystals grown by the two-step MCZM growth process