INFLUENCE OF O2 AND OXIDE ON CL/SI SURFACE-REACTIONS

Variation of Si(111) and Si(100) surface conditions under sequential Cl2 exposure, O2 exposure, and other O-related treatments are examined by Auger electron spectroscopy (AES) and low-energy electron energy loss spectroscopy (LEELS). Cl-adsorbed Si surfaces, particularly Cl-adsorbed Si(111) surfaces, have a passivation effect under dry O2 atmosphere, where O adsorption and oxidation are suppressed. On the other hand, Cl desorption and oxidation take place immediately on Cl-adsorbed surfaces when exposed to wet environments: humid clean-room air or de-ionized water. When O2-treated Si surfaces are exposed to Cl2 atmospheres, Cl adsorption occurs on SiO(x) but not on SiO2.