Effects of implantation temperature on damage accumulation in Al-implanted 4H-SiC

Damage accumulation in 4H-SiC under 1.1 MeV Al-2(2+) irradiation is investigated as a function of dose at temperatures from 150 to 450 K. Based on Rutherford backscattering spectroscopy and nuclear reaction analysis channeling spectra, the damage accumulation on both the Si and C sublattices have been determined, and a disorder accumulation model has been fit to the data. The model fits indicate that defect-stimulated amorphization is the primary amorphization mechanism in SiC over the temperature range investigated. The temperature dependence of the cross section for defect-stimulated amorphization and the critical dose for amorphization indicate that two different dynamic recovery processes are present, which are attributed to short-range recombination and long-range migration of point defects below and above room temperature, respectively. As the irradiation temperature approaches the critical temperature for amorphization, cluster formation has an increasing effect on disorder accumulation, and ion flux plays an important role on the nature and evolution of disorder. Dislocation loops, which are mostly formed under high ion flux, act as sinks for point defects, thereby reducing the disorder accumulation rate. (C) 2004 American Institute of Physics.