Characterization of thermally oxidized Ti/SiO_2 gate dielectric stacks on 4H-SiC substrate

摘要

The structural and electrical characteristics of thermally oxidized Ti/SiO_2 gate dielectric stacks on 4H-SiC substrates have been investigated. X-ray photoelectron spectroscopy shows a good stoichiometry of TiO_2 films formed by thermal oxidation of evaporated Ti. No evidence of the formation of titanium silicide at the surface as well as in the interfacial layer was observed. Electrical measurements show, in particular, no signature of an increase in interface state density towards the conduction band edge of 4H-SiC. The improved leakage current with higher breakdown field of 11 MV/cm makes TiO_2/SiO_2 stacks a potential gate insulator for high-power SiC devices.