In this work we develop the thermoelastic analysis for prediction of slip defect generation on (001) GaAs wafers, by means of the finite element method taking into account the anisotropic structure and slip system of dislocation. The analysis for a completely circular wafer predicts that longer slip defect lines are generated at the wafer edge of θ=π/8+Δ+nπ/2, 3π/8-Δ+nπ/2 (Δ is about 3°) and the prediction well agrees with the result of the wafer heating experiment. This demonstrates that our anisotropic analysis is more accurate than simple isotropic analysis which predicts slip defect generation at the wafer edge of θ=π/8+nπ/4. According to this thermoelastic analysis, we can additionally confirm that longer slip defect lines are more prone to be generated at the <110> orientation flat (OF) edge than at the circular edge. Finally, we suggest the method of preventing slip defect generation.

In this work we investigate the mechanism of slip defect generation, using a simple heat flow simulation during an MBE process, a wafer heating apparatus, and a thermoelastic analysis from a crystallographic viewpoint. We find that the slip defect pattern predicted from the analysis agrees with the experiment and confirm that slip defects are prone to occur at orientation flat (OF) and notch edge.

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