Ion Implantation Synthesis of Silicon Carbide
Silicon wafers with 200A of carbon deposited on the surface were implanted with 50 keV N⁺ ions at a dose of 1x10¹⁶ ions/cm² at room temperature. The implanted samples were cut to several pieces and annealed in vacuum (at a pressure of 5x10⁻⁸ torr) at temperatures of 800°C and 900°C, and inert gas at a temperature of 1000°C for 30 minutes. RBS analysis shows that after implantation carbon is distributed in the range of 0 to 1000A beneath the silicon surface, and the silicon substrate shows a disordered range of about 1400A. Carbon atoms follow an apparent Gaussian distribution in silicon substrate that is consistent with the theoretical predictions. After annealing, a buried or near surface silicon carbide grains in host silicon matrix was formed, and the disordered range narrowed. A maximum C/Si ratio of about 0.2 or less was measured for all the samples.
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