IRRADIATION-INDUCED AMORPHIZATION IN BETA-SIC

Single-crystal (001) beta-SIC (3C) films have been irradiated with 360 keV Ar2+ ions at 175, 310 and 375 K and the damage accumulation after each incremental fluence has been measured insitu by Rutherford backs cattering spectroscopy in channeling geometry (RBS/C) along the [011] direction using the dual beam facilities within the Ion Beam Materials Laboratory at Los Alamos National Laboratory. The relative rate of di sordering along [011] decreases with increasing temperature. The criti cal dose for the relative disorder to reach the random level along [01 1] is 0.35 dpa (17.5 eV/atom), 0.44 dpa (22.0 eV/atom) and 0.61 dpa (3 0.5 eV/atom) at 175, 310 and 375 K, respectively. The sigmoidal increa se in relative disorder with dose is consistent with defect accumulati on processes. Although RBS/C along [011] indicates a fully random laye r at the highest dose for each temperature, ex situ RBS/C and XTEM alo ng [001] indicate some residual crystallinity remains near the surface and the end of range. (C) 1998 Elsevier Science B.V.