COMPARISON OF THE ANNEALING BEHAVIOR OF HIGH-DOSE NITROGEN-IMPLANTED,ALUMINUM-IMPLANTED, AND BORON-IMPLANTED 4H-SIC

Room temperature free carrier concentrations exceeding 1 X 10(18) cm(- 1) have been achieved with 1000 degrees C implants into 4H-SiC using N and Al (1 X 10(17) cm(-3) using B). A decrease in resistivity is obse rved for annealing temperatures above similar to 1300, similar to 1500 , and similar to 1750 degrees C for N, Al, and B, respectively. Ruther ford backscattering spectroscopy measurements indicate almost complete recrystallization for N-implanted samples and partial recrystallizati on on the silicon, but not the carbon, sublattice for B- and Al-implan ted samples. An implant and species related step formation is also obs erved. Only boron is observed to diffuse appreciably. A crystal stoich iometry and Fermi level dependent model is proposed to explain the act ivation results. (C) 1998 American Institute of Physics.