CONTROL OF AS PRECIPITATION IN LOW-TEMPERATURE GAAS BY ELECTRONIC ANDISOELECTRONIC DELTA-DOPING

A systematic study of electronic (Si and Be) and isoelectronic (In and Al) delta-doping effects on the formation of arsenic precipitates in GaAs grown by molecular beam epitaxy (MBE) at low substrate temperatur e is presented. Both electronic dopant Si and isoelectronic dopant In are found to accumulate As precipitates in postgrowth-annealed samples , while the precipitate accumulation effect is more prominent for Si t han In. As precipitate is depleted from regions doped with Be or Al. T he results suggest that the electronic property of impurity does not h ave a direct correlation with the As precipitation process. The effect s of doping concentration and postgrowth annealing temperatures are al so reported. The ability to control the As precipitates in low-tempera ture materials should lead to a wide variety of device applications.