X-RAY CHARACTERIZATION OF SI DELTA-DOPING IN GAAS

High-resolution triple-axis x-ray diffractometry has been used to exam ine the structural properties of a delta-doped superlattice of sixty p eriods, each consisting of half a monolayer of Si and 500 angstrom of GaAs, grown by molecular beam epitaxy (MBE) at 400-degrees-C under an arsenic flux. The measurements indicated that the superlattice was of high structural quality. Using dynamical simulation, it was demonstrat ed that the period variation was equal to 3%, while the silicon spread ing was no greater than 2 monolayers. It was possible to extract this information because of the high-resolution diffractometer which produc ed the theoretical line shape and wide dynamic range. Using a simple m odel, it was deduced that virtually all Si atoms were located on Ga la ttice sites.