CALCULATION OF STRESSES IN IN0.12GA0.88AS TERNARY BULK CRYSTALS WITH COMPOSITIONALLY GRADED IN1-XGAXAS LAYERS ON GAAS SEEDS

A theoretical model is proposed to calculate the stress distribution in a crystalline heterostructure under consideration of the difference between lattice constants of the constituent crystal layers. This model is applied to calculate the stress distribution in the structure In0.12Ga0.88As ternary bulk crystal/compositionally graded In1-xGaxAs (0.88 less-than-or-equal-to x less-than-or-equal-to 1) layer/GaAs seed, which is one of the candidates to obtain ternary In0.12Ga0.88As bulk crystals with small stresses. It is found that the stress in the bulk crystals can be reduced using thick graded layers. The curvature radius of the structure was calculated as a function of thickness of the graded layer.