Rapid formation of carbon-related defects in SiC induced by SiO desorption from thermally grown and ALD-deposited SiO 2 /4H-SiC(0001) stacks

In this study, we investigate how retaining SiO 2 on 4H-SiC affects carbon-related defect formation in the near-surface region of SiC during Ar annealing at 1500 ℃. The carbon-related defects in SiO 2 /SiC stacks were characterized by attenuated-total-reflection Fourier-transform infrared spectroscopy for the samples in which SiO 2 was prepared by either thermal oxidation or atomic-layer deposition. The peak associated with carbon-containing structures rapidly increased as SiO 2 thickness decreased through the SiO 2 /SiC interfacial reaction generating volatile SiO. Another peak correlated with the structures containing both carbon and oxygen appeared only in thermally oxidized samples. These results indicate that the retained SiO 2 film acts as a reactant to trigger the formation of carbon-related defects in the near surface region of SiC rather than as an inert protective layer when SiO 2 /SiC stacks are annealed at a high temperature.