Reaction of SiO2 with hafnium oxide in low oxygen pressure

Abstract

A dynamic process consisting of a series of reactions during deposition of HfO2 films on SiO2-covered silicon under oxygen-deficient conditions is identified. The oxygen-deficient HfOx<2 layer absorbs the oxygen in the SiO2 layer to form fully oxidized metal oxide film. As a result, there is no silicate and silicon oxide formed at the interface with silicon substrate. Thermodynamic analysis indicates that even if there is a layer of silicate forming at the initial stage of deposition, the silicate layer will be decomposed with the progress of HfOx<2 deposition.