ARSENIC PRECIPITATE ACCUMULATION IN ALTERNATELY SI BE DELTA-DOPED GAAS GROWN BY LOW-TEMPERATURE MOLECULAR-BEAM EPITAXY/

The precipitation of arsenic in alternately [Si]=1.0 x 10(13) cm(-2) a nd [Be]=1.0 x 10(14) cm(-2) delta-doped GaAs grown at low temperature by molecular beam epitaxy has been studied using transmission electron microscopy. Following annealing at 600, 700 and 800 degrees C, As pre cipitates were found to form preferentially not only on planes of Si b ut also on planes of Be. The as-grown and annealed samples were also c haracterized using secondary ion mass spectroscopy, and the results re vealed that the interdiffusion of Si and Be dopants due to annealing w as discernible. This is the first observation of As precipitate accumu lation on Be delta-doped planes in low-temperature grown GaAs.