Scaling of dislocation cells in GaAs crystals by global numeric simulation and their restraint by in situ control of stoichiometry

Undoped GaAs crystals show dislocation cell patterns with cell dimensions of some hundred micrometer orders of magnitude larger than in metals. Nevertheless, the correlation between cell diameter and dislocation density obeys the same Holt relation. Experimental results of dislocation analysis in GaAs were correlated with global computation of the resolved shear stress distribution at growth relevant temperatures and scaled with the universal function d = Kρ−1/2 = αKGbτ−1, where d is the cell size, ρ the dislocation density, K, α the constants, G the shear modulus, b the magnitude of Burgers vector and τ is the resolved shear stress. Samples grown with in situ control of stoichiometry show nearly no dislocation patterning due to the minimised native point defect content needed for dislocation climb.