Heavily Si-doped (5 x 1019/cm3) low-temperature GaAs, sandwiched between undoped low-temperature GaAs layers, was grown by using molecular beam epitaxy and was annealed at up to 900C. Transmission electron microscopy showed that, within the first few minutes of annealing, an accumulation of As precipitates formed near to each doped/undoped low-temperature interface. During further annealing, Si segregation to As precipitates was detected, using secondary ion mass spectroscopy, in the form of delta-like peaks at the As precipitate accumulations. It was found that the Si diffusion coefficient was initially independent of concentration, at a value of 2.5 x 10-13cm2/s, and was comparable to diffusion under intrinsic conditions in As-rich material when grown at normal temperatures. During annealing for 1h, the Si concentration in the As precipitates reached 2.5 x 1020/cm3.

Si Diffusion and Segregation in Low-Temperature Grown GaAs. K.L.Kavanagh, J.C.P.Chang, P.D.Kirchner, A.C.Warren, J.M.Woodall: Applied Physics Letters, 1993, 62[3], 286-8