Synchrotron radiation photoemission spectroscopic study on the room temperature oxidation of Si(001); H formed by hyperthermal atomic/molecular beams

Tagawa, Masahito*; Yokota, Kumiko*; Yoshigoe, Akitaka ; Teraoka, Yuden

A laser detonation atomic beam method forms intense, hyperthermal, pulsed broad atomic/molecular beams. Translational energy of impinging atoms ranging 1-10eV can promote surface chemical reactions without activating physical sputtering. Therefore, atomic beams with hyperthermal energies are effective for lowering a process temperature of surface modification. In this study, an Si(001):H surface was exposed to hyperthermal O-atom beam at room temperature and the surface oxide film formed was analyzed by synchrotron radiation photoemission spectroscopy at BL23SU in SPring-8. It was made clear that the oxide film formed by a hyperthermal O-atom beam exhibited some unique features. (1)The atomic beam oxide film contains less amount of suboxides compared with conventional high-temperature oxidation. (2)A distribution of suboxide is different from high-temperature oxidation; i.e., suboxides concentrated at SiO surface rather than Si/SiO interface. The suboxide distribution can be explained by the back diffusion of interstitial Si atom. (3)An impinging energy affects the direct oxidation reaction. (4)Silicon nitride can also be formed by hyperthermal N/N beam.