Open Access

ARTICLE

Effect of Growth Direction on Twin Formation in GaAs Crystals Grown by the Vertical Gradient Freeze Method

by A.N. Gulluoglu¹, C.T. Tsai²

1 Department of Material Science and Engineering, Marmara University, Goztepe, Istanbul, Turkey.
2 Department of Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA.

Computer Modeling in Engineering & Sciences 2000, 1(1), 85-90. https://doi.org/10.3970/cmes.2000.001.085

Abstract

Twins in growing crystals are due to excessive thermal stresses induced by the temperature gradients developed during the growth process. Twinning is an important defect in advanced semiconductor crystals such as GaAS and InP. The objective of this study is to develop a computational model to predict the twin formation in the Gallium Arsenide (GaAs) crystals grown by the vertical gradient freeze method (VGF). A quantitative quasi-steady state thermal stress model is developed here for predicting the twinning formation in GaAs grown by VGF. The thermoelastic stresses in VGF grown crystal are calculated from a two-dimensional finite element analysis. Deformation twins form as a result of the high shear stresses acting on the twinning plane and in twinning direction. In the study, the resolved shear stress (RSS) distributions in the twin systems for different growth directions have been calculated. This investigation is expected to further the understanding of twinning formation during crystal growth for different growth direction.

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Keywords

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