Electron-beam doping of Si into GaAs: The annealing behaviour of photoluminescence

Abstract

Si impurities are introduced in (100)-oriented undoped semi-insulating GaAs at 50°C by using an electron-beam doping method from a Si impurity sheet, which is in contact with a GaAs surface. The Si surface is irradiated with a fluence of ∼ 5 × 10 17 electrons cm −2 at 7 MeV. Before and after annealing at 300°C for 20 min with a SiO 2-cap layer, the photoluminescence spectra at 77 K indicate two dominant peaks which are probably attributed to silicon acceptors, Si As, at 1.48 eV and gallium antisite defects, Ga As, at 1.445 eV. When the annealing temperature is higher than 600°C, the band-gap transition spectra appear at 1.51 eV. The hole concentration for a sample annealed at 700°C is measured to be 1–4 × 10 16 cm −3 with a nearly constant depth distribution in the range of 0.5–5 μm.