Formation process of 1 ML oxide on Si(110) surface and development of interfacial bonding structures

Yamamoto, Yoshihisa*; Togashi, Hideaki*; Kato, Atsushi*; Suemitsu, Maki*; Narita, Yuzuru*; Teraoka, Yuden; Yoshigoe, Akitaka 

Formation processes of one atomic oxide layer and time evolution of chemical bonding states at the interface were investigated by using real-time photoemission spectroscopy with synchrotron radiation. Time evolutions for oxide components (Si:n=1-4) of Si2p photoemission spectra, observed in the conditions of 813K substrate temperature and 1.110 Pa O pressure, were analyzed. Rapid increase of Si component until oxygen dose of 10 L indicates existance of a reaction path through the Si state. On the other hand, contrary to the Si(001) oxidation, the Si component was larger than the Si component during oxidation. Reaction mechanisms was considered from these facts. Oxygen insertion into chain-like Si-Si bonds densely existing on the (110) surface (A bond) and Si-Si bonds on the (-110) surface is an origin of the first layer oxidation at Si(110) surface. The A bonds may be oxidized partially due to storage of oxidation strains.