Carbon Ejection from a SiO2/SiC(0001) Interface by Annealing in High-Purity Ar

We found that carbon-associated byproducts formed at the dry-oxidized SiO2/SiC(0001) interface could be decomposed and be taken out to the SiO2 side by high-purity Ar annealing. We evaluated the concentration of the ejected carbon atoms in the SiO2 by secondary ion mass spectrometry, and discovered that it clearly depends on the condition of oxide formation (dry-oxidation, nitridation treatment, and phosphorus treatment). This work provides an indirect but unambiguous evidence for the carbon-byproducts existing at the SiO2/SiC interfaces, and also indicates that the phosphorus treatment removes the carbon-byproducts, leading to significant reduction of interface defects.