Removal of Surface Organic Contaminants during Thermal Oxidation of Silicon

The behavior of surface hydrocarbons and carbon during thermal oxidation of silicon is studied. It was established that organic contaminants are readily volatilized and do not affect, in a significant manner, the oxidation kinetics only in the case when the silicon surface during contamination is hydrophilic. The organic removal process is substantially more effective at the higher temperatures of oxidation (900°C and above) than at the low temperature of 700°C. In the latter case, a noticeable disruption of the oxidation kinetics due to organic contaminants was observed for hydrophobic surfaces, or surfaces subjected to step last. The results obtained indicate that contamination of silicon surfaces prior to oxidation with trace organics is of no major concern only when the silicon surface prior to oxidation is covered with an oxide at least 5–10Å thick.