Electron beam doping of Si into GaAs in the overlayer Si/substrate GaAs and the sandwiched system of GaAs/Si/GaAs

Abstract

Si atoms were introduced in (100)-oriented undoped semi-insulating GaAs at 50 ° C by using an electron-beam doping method from a Si sheet. A Si sheet with a thickness t of ∼ 0.5 mm was sandwiched between two wafers of GaAs: GaAs (layer 3)/Si (layer 2)/GaAs (layer 1) (sandwiched array). The surface of layer 3 was irradiated with a fluence of 5 × 10 17 electrons cm −2 at 7 MeV. After annealing at 800 ° C for 20 min with a SiO 2 cap, the 0.6 mm thick GaAs wafers (the layers 1 and 3) converted to p-type, and the peak carrier concentrations at the surfaces of layers 1 and 3, which were in contact with the Si surface, were ∼ 3X10 17 and ∼ 4x10 17 cm −3, respectively. The photoluminescence spectra at 77 K for layers 1 and 3 indicated two dominant peaks, which were attributed to the Si acceptor, Si As,, at 1.48 eV and to the band gap transition at 1-51 eV. In the case of the sandwiched array electron-beam doping was experimentally determined to be more effective than in the case of the two layer array (an overlayer Si/substrate GaAs).