Asymmetric strain distributions resulting from deliberately induced misfit dislocations

Abstract

Misfit dislocations oriented in a specific 〈110〉 direction have been produced in strained Si1−xGex epitaxial layers deposited on Si(001), using sites of localized crystallographic damage as dislocation sources. During a high-temperature anneal, misfit dislocation propagation from a series of parallel saw lines oriented along a particular 〈110〉 direction led to asymmetrically strained material demonstrating an orthorhombic symmetry. Processing conditions required to maximize [110]/[11̄0] asymmetry in the strain distribution are discussed. The distance of a dislocation front emanating from the sites of crystallographic damage during a high-temperature anneal has been used to measure the misfit dislocation glide velocity.