Effect of excess vacancies in ion beam synthesis of SiC nanoclusters

SiC nanoclusters are synthesized in Si by simultaneous dual implantation using two ion beams, of C and Si ions. This implantation mode is associated with extra excess vacancy generation. The effect of vacancies on SiC synthesis is investigated in this study. The amount of synthesized SiC is compared for different implantation modes, simultaneous and sequential ones. Sequential pre-deposition of vacancy defects in Si before the C implantation is performed by additional Si and He implantation. The simultaneous dual beam implantation is found to be the only method to improve SiC synthesis. The generation of both excess and He induced vacancies by a sequential implantation process is disadvantageous for SiC nanocluster formation. The pre-deposition of vacancy defects is accompanied by higher crystal damage and/or the defects are annealed out during the subsequent C implantation at temperatures above 400 °C. Vacancies must be created “in-situ” during C implantation to achieve enhanced output of SiC.