X-ray characterization of Si δ-doping in GaAs

Abstract

High-resolution triple-axis x-ray diffractometry has been used to examine the structural properties of a δ-doped superlattice of sixty periods, each consisting of half a monolayer of Si and 500 Å of GaAs, grown by molecular beam epitaxy (MBE) at 400 °C under an arsenic flux. The measurements indicated that the superlattice was of high structural quality. Using dynamical simulation, it was demonstrated that the period variation was equal to 3%, while the silicon spreading was no greater than 2 monolayers. It was possible to extract this information because of the high-resolution diffractometer which produced the theoretical line shape and wide dynamic range. Using a simple model, it was deduced that virtually all Si atoms were located on Ga lattice sites.