Post-implantation defects instability under 1 MeV electron irradiation in GaAs

The influence of 1 MeV electron irradiation on the stability of post-implantation defects in GaAs has been investigated. The n-type GaAs wafers of <100> orientation were implanted with 150 keV As+ ions below the amorphization threshold at RT using the implantation dose of 2x10(13) ions cm(-2) at a constant flux of 0.1 muA cm(-2). Then the implanted samples were irradiated with a scanned beam of 1 MeV electrons from a Van de Graaff accelerator in a dose range (0.5-5.0)x10(17) cm(-2) at 320 K. RBS and channeling spectroscopy of 1.7 MeV He-4(+) ions were used to determine the depth distribution of defect concentration before and after 1 MeV irradiations. New results of an "oscillatory" behaviour of the damage level as a function of 1 MeV electron fluence are presented.