AS PRECIPITATE REDISTRIBUTION IN SI DELTA-DOPED LOW-TEMPERATURE GAAS

A high-resolution x-ray diffractometer and transmission electron micro scope (TEM) are used to characterize the redistribution of As precipit ates in Si delta-doped GaAs grown by molecular-beam epitaxy at low sub strate temperature (230 degrees C). The analysis results indicate that superlattice satellite peaks, as observed for samples annealed at 700 -900 degrees C for 10 min, are attributed to the formation of the GaAs /As superlattice. Also; the intensity of satellite peaks in x-ray rock ing curves and TEM observations reveals the varying degree of As preci pitates confined on the Si delta-doped planes. Furthermore, the asymme try of the satellite peaks clearly indicates the lattice expansion and contraction of the annealed low-temperature epitaxial layers.