Diagnostics of hydrogen role in the Si surface reaction processes employing in-situ Fourier transform infrared-attenuated total reflection

The oxidation process of H-terminated amorphous Si film on Ge and the reaction mechanism of the triethylsilane (TES)/H system which allows us to deposit an organic Si film conformably have been investigated employing in-situ FTIR(Fourier transform infra red)-ATR(attenuated total reflection). This measurement was demonstrated to be a sensitive and simple method to inspect the role of H(hydrogen) in their surface reactions. In the Si oxidation case, the H-terminated Si is readily oxidized by O(oxygen) atoms. The oxidation with O2 molecules proceeds gradually as the breaking of Si-H bonds and forming of H-Si-O bonds due to binding of O atoms with the back bond of Si for 700 min. After about 700 min, dissociated O atoms rapidly penetrate the Si film, and oxidize the bulk Si, leaving both Si-H and H-Si-O bonds still on the Si surface. Next, in the TES/H reaction system, gas phase FTIR spectra obtained by reactions of H atoms or H2 molecules with TES do not show appreciable change in a wide range of pressure. Nevertheless, in-situ FTIR-ATR reveals that TES reacts easily with H atoms on the surface, desorbing H2, methyl and ethyl groups.