Real-time SR-XPS and in-situ STM studies on the initial oxidation of Si(110)-162 surface

Suemitsu, Maki*; Togashi, Hideaki*; Takahashi, Yuya*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka ; Asaoka, Hidehito  

Si(110) surface has attracted much attention for its use in the next-generation high-speed and highly-integrated devices. We have investigated the effect of mild annealing on the RT-oxidized Si(110)-162 surface by using SR-XPS and STM. After an annealing at 573K for 15min, the Si2p spectrum presented a decrease in the relative intensities of Si and Si suboxides and an increase in those of Si and Si suboxides, indicating clustering of oxygen atoms. The STM image from the annealed surface actually presented a clustered structure named "DD site", at which clustered Si adatoms appear dark for both the filled and the empty states. As far as the oxidation of Si(110) clean surface is concerned, it was clarified that there is an oxidized state that is observed completely dark by STM.