GROWTH-MECHANISM OF 3C-SIC LAYERS AT A LOW-TEMPERATURE REGION IN LOW-PRESSURE CVD

The growth mechanism of 3C-SiC layers on Si substrates in the temperature region lower than 1300-degrees-C has been studied in low-pressure CVD using SiH4 and C2H2 as source gases. The growth rate is dominated by the flow rate of SiH4 and is independent of that of C2H2. Stoichiometric SiC layers grow independent of the source gas composition ratio of SiH4 up to 90%. The growth mechanism is considered as follows: Adsorption of silicon atoms occurs onto the carbon covered surface and this leads some silicon to form SiC molecules and the rest to desorb from the surface. Layers with high crystallinity are grown when the growth rate is controlled to be within 4 nm/min at 1150-degrees-C. This was achieved by controlling the SiH4 supply.