Difference of near-interface strain in SiO2 between thermal oxides grown on 4H-SiC by dry-O2 oxidation and H2O oxidation characterized by infrared spectroscopy

Structural difference of near-interface oxides at thermally grown SiO2/4H-SiC interfaces between dry-O-2 oxidation and H2O oxidation was investigated using infrared spectroscopy for both on Si- and C-faces. We found that H2O oxidation results in a significant reduction of the intrinsic strain of SiO2 in the near-interface region compared to dry-O-2 oxidation, while such strain was not affected by the change of oxidation temperature and O-2 partial pressure in the case of dry-O-2 oxidation. The peak broadness observed in the near-interface region was also smaller for H2O oxidation than for dry-O-2 oxidation, which indicated a formation of an oxide with more uniformity in microscopic structures. A strong correlation between the strain of near-interface oxides and the formation of near-interface oxide traps was suggested from the clear difference of the characteristics of metaloxide- semiconductor capacitors fabricated with different oxidants. Published by AIP Publishing.