Crack formation in tensile strained III-V epilayers grown on InP substrates

摘要

Layers of InxGaAlx.xAs with x<0.53 grown on InP(OOl) are under tension. Beyond a critical thickness, governed by the lattice misfit, such layers prefer to relieve their stored energy by crack formation. In this paper, experimental observations of this critical thickness over a range of misfits are compared with the predictions of a simple theory. Measurements of crack profiles and separations have allowed us to estimate the amount of stored elastic energy in such layers and explain why cracks penetrate beyond the epilayer into the substrate.