Abstract
In the research, to describe the spinodal decomposition of A³B⁵ semiconductor solid solutions, in which the substitution of the main components occurs simultaneously in each of the sublattices of the sphalerite crystal structure, the Cahn-Hilliard concepts are extended. The resulting system of differential equations is applied to describe the effect of composition modulation in Ga_xIn_1-xP_yAs_1-y solid solutions grown on InP substrates. In this case, the elastic deformation energy of a thin layer of Ga_xIn_1-xP_yAs_1-y solid solution is calculated on the assumption of its coherent conjugation with a massive InP substrate. The excess mixing of the components in the solid phase is evaluated in accordance with the simple solution model. The temperature-concentration ranges, in which the conditions for the occurrence of an oscillatory mode of relaxation of the supersaturated metastable state of the solid phase are realized, are found by analyzing phase portraits of the system. The performed analysis shows that the effect of modulation of the material composition is connected with the resonance of total entire excess energy and elastic energy. The parameters of the oscillatory process are compared with data on the effect of composition stabilization, which is experimentally observed in the growth of elastically stressed heterostructures Ga_xIn_1-xP_yAs_1-y – InP substrate.

Key words
semiconducting III-V materials, solid solutions, phase equilibrium, spinodal decomposition, stresses, crystal structure

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