The Role of SiO in Si Oxidation at a Si-SiO2 Interface

Abstract

Deal and Grove (1) modeled thin oxide growth by a Si-SiO2 interfacial reaction whose rate is expected to vary linearly with time and exhibit a first order dependence on oxidant pressure. Deviations from this model, which increase with a decrease in temperature, are observed during oxidation in dry O2 for oxides ≤ 30 nm thick. To account for the unexplained thin oxide growth process, it was proposed (2) that molecular SiO is formed in parallel with SiO2. SiO formation and transport from the Si-SiO2 interface into SiO2 are identified as as a parallel oxidation process that originate at the interface and that affect Si02 growth. Experimental studies supporting this previously proposed model show a) evidence of significant SiO transport for oxide films that are ≲ 30 nm thick and b) that oxidation to SiO2 is inhibited by blocking the intermediate step in which SiO forms.