General characteristics of crack arrays in epilayers grown under tensile strain

A simple model is presented to describe the formation of cracks, the expected population density and their depth in tensile strained epilayers. It is shown that the critical thickness for crack formation is expected to be constant across a broad range of simple materials. The crack depth, crack spacing and critical thickness predicted by the model are shown to agree well with experimental observations on III-V compound semiconductors. Inefficiencies in the crack generation process are discussed in terms of crack vibration.