OXIDATION AND 6H-SIC-SIO2 INTERFACES

For hexagonal SiC the oxidation is slower for the Si-terminated surface as compared to the C-terminated surface. This has been related to an unknown interface compound. Our angle resolved x-ray photoelectron spectroscopic (ARXPS) analysis of oxidized Si-(OOl) and C-(001) surfaces of 6E/-SiC reveals the interface oxide Si4C4xO2 (x<2), seemingly a reaction product of a peroxidic O2 bond to a SiC double layer. This oxide occurs in larger thickness (— 1 nm) at the slowly oxidizing Si-(OOl) surface, whereas the C-(001) surface shows smaller amounts, only, diminishing fast with oxidation above 1000 K. Evidence is presented that the oxidation of SiC to SiO2 is retarded by a Si4C4_xO2 interface layer. Our ARXPS analysis is consistent with amorphous SiO2 containing less than 3% Si4C4O4 as oxidation product of Si4C4_xO2. © 1995, American Vacuum Society. All rights reserved.