Vibrational study on the carbonization of Si surface

The initial carbonization of Si (100) and (111) in the temperature range 600–1200°C, under atmospheric pressure, was investigated by probing changes of the surface Si–H vibrational modes using FTIR-ATR. When the samples were exposed to C3H8 with H2 at 1000°C, without cooling down after in-situ etching, both Si–H vibrational modes associated with carbonization and Si–H vibrational modes indicating a H-terminated clean Si surface were observed simultaneously. This indicates that initial carbonization occurred as an island growth mode. When the samples were exposed to C3H8 with H2 and heated up to the temperature range 600–1200°C, with a cooling down process after in-situ etching, Si–H vibrational modes associated with carbonization with broad spectral feature were obtained in the temperature range 1050–1200°C. This indicates that the carbonized surfaces were microscopically rough.