Epitaxially grown n-type films, doped with Si to concentrations of 2 x 1015 or 2 x 1016/cm3, were exposed (at room temperature) to 200, 350, and 500MeV proton irradiation using fluences of between 3 x 1011 and 1015/cm2. The effects of irradiation were determined by means of low-temperature continuous photoluminescence spectroscopy. Two radiation-induced donor-to-acceptor transitions were observed. One at 1.476eV was associated with the Ga vacancy acceptor, VGa, and the another at 1.482eV was related to Si at an As site acceptor, SiAs. The relative introduction rates of these 2 defects were measured in irradiated samples, before and after annealing (550C, 0.5h). The introduction rates were higher than those predicted by relativistic elastic scattering cross-section theory for the energy range which was used here. It was concluded that inelastic scattering contributed to the cross-section. The introduction rates were lower than those predicted by non-ionizing energy loss calculations in the 200 to 500MeV energy range. It was suggested that the proton inelastic scattering parameter which was used in non-ionizing energy loss calculations required reconsideration. A relativistic inelastic scattering formula gave better agreement with experimental data.

C.Carlone, M.Parenteau, A.Houdayer, P.Hinrichsen, J.Vincent: IEEE Transactions on Nuclear Science, 1997, 44[6], 1856-61