Thermal stability of beryllium atoms in Be δ-doped GaAs grown on GaAs(111)A by molecular beam epitaxy

We report on the thermal stability of Be in δ-doped GaAs layers grown on misoriented GaAs(111)A substrates. The diffusion coefficients of Be tend to become large as the substrates are misoriented from (110) to (001). These diffusion coefficients of Be are larger than those of Si used as a p-type dopant. The estimated activation energy of Be diffusion on GaAs(111)A is 1.42±0.12 eV and is smaller than that of Si-acceptor. This study indicates that the diffusion of Be is due to an interstitial diffusion mechanism; this is in contrast to that of Si-acceptor, which is due to a vacancy diffusion mechanism.