ANALYSIS OF THE SHORTCOMINGS OF THE MATTHEWS-BLAKESLEE THEORY OF CRITICAL THICKNESS AT HIGHER STRAINS

The Matthews-Blakeslee equilibrium theory provides predictions of the critical thickness of a strained heteroepitaxial layer as a function o f misfit strain and material constants. At low strains the prediction is double Valued with one value producing a physically reasonable resu lt for the critical thickness. At higher strains, no prediction is pro vided at all. It is shown that these features arise from a particular approximation which increases in importance for larger strains and hen ce for reduced critical layer thickness. A correction is proposed whic h lessens the influence of this approximation and which provides a sin gle-valued prediction for all layer thicknesses, thus extending the us eful range of applicability of the Matthews-Blakeslee theory.