DIFFUSIVITIES AND ACTIVITIES OF S IMPLANTED INTO GAAS THROUGH AN AS-DOPED A-SI-H FILM

Sulfur (S) ions are implanted at 500 keV into GaAs through 120 nm a-Si :H films doped with arsenic atoms at a concentration of 2 x 10(20) cm( -3). The samples are annealed in Ar gas at temperatures of 700-1000 de grees C for 15 min. The sheet carrier concentration increases with inc reasing implant dose and annealing temperature. The diffusivity of the S atoms decreases with increasing implant dose. Silicon (Si) atoms ar e also doped from the a-Si:H films into GaAs during annealing and S+ i mplantation. The distribution of the Si atoms becomes slightly shallow er as the implant dose increases. The carrier concentrations, however, are left unchanged by Si doping.