Carbon impurities at a Si-SiO₂ interface

During post-oxidation annealing of Si-SiO2 structures in inert ambients at elevated temperatures, an interfacial reaction occurs in which β-SiC is thermally oxidized at a Si-SiO2 interface. Precipitates of β-SiC are identified at the interface after adding molecular SiO to the anneal ambient. When SiO concentrations are reduced, oxidation occurs at SiC impurity sites. The reaction is detected from voids that form in the oxide film as SiO2 and interfacial β-SiC are consumed.. The annealing studies indicate that interfacial carbon impurities are oxidizable and will react in parallel with Si during thin SiO2 growth in O2. The role of carbon contamination during oxidation is reviewed with emphasis on those factors that affect accumulation and oxidation of SiC at the interface. © 1993.