IN-SITU X-RAY PHOTOEMISSION SPECTROSCOPIC STUDIES OF AL SIO2 INTERFACE FORMATION/

A structural model for the Al/SiO2 interface system after an oxidation -reduction reaction is proposed. Thermal dependence of the initial sta ges of the Al/SiO2 interface formation process is investigated by in s itu x-ray photoemission spectroscopy analysis and secondary ion mass s pectrometry measurements of depth profiles. An abrupt interface withou t any reaction is confirmed when the interface is formed at room tempe rature. During Al deposition on SiO2 at substrate temperatures beyond 300 degrees C, oxidation-reduction reaction occurs that produces Al2O3 and reduces metallic Si at the interface. The reduced Si spreads thro ughout the entire Al layer uniformly and the thin Al2O3 layer acts as a diffusion barrier that limits the reaction in the very vicinity of t he interface. This suggests a distinct layer ordering of the reacted s ystem, Al(Si)/Al2O3/SiO2.