Low pressure chemical vapor deposition of silicon carbide from dichlorosilane and acetylene

The deposition of silicon carbide thin film on Si (1 0 0) wafer, using low pressure CVD of SiH2Cl2/C2H2/H2 reaction system, is investigated. The SiC film deposited at 1023 K is amorphous, 1073 K is microcrystalline, and 1173 K is (1 1 0) preferentially oriented. The deposition rate increases significantly with temperature. Deposition kinetics of surface and gas-phase paths is separated by varying the volume/surface ratio of deposition environment. The activation energy for gas-phase reaction path is estimated to be 76 kcal/mol, and that for surface reaction path is 71 kcal/mol. The experimental barrier for gas-phase reaction path is close to the values by ab initio calculation (Su and Schlegel), which range from 73 to 76 kcal/mol for the step of H2 elimination from SiH2Cl2.