Critical thicknesses of highly strained InGaAs layers grown on InP by molecular beam epitaxy

Abstract

The growth and relaxation of highly strained In82Ga18As and InAs epilayers grown by molecular beam epitaxy, at 525 and 450 °C, on InGaAs lattice matched (LM) to InP, have been investigated using reflection high energy electron diffraction (RHEED) techniques. RHEED oscillations, three-dimensional growth mode onsets, and relaxation onsets have been measured. Strong strain and temperature effects have been observed on both growth mode and plastic relaxation mechanism. It is suggested that plastic relaxation could occur through two competing mechanisms, misfit dislocations or ‘‘3D island dislocations’’ and that the actual mechanism can be predicted using specific temperature dependent laws for the critical thicknesses.