Band offsets and electronic structure of SiC/SiO2 interfaces

Abstract

The electronic structure of SiC/SiO₂ interfaces was studied for different SiC polytypes (3C, 4H, 6H, 15R) using internal photoemission of electrons from the semiconductor into the oxide. The top of the SiC valence band is located 6 eV below the oxide conduction band edge in all the investigated polytypes, while the conduction band offset at the interface depends on the band gap of the particular SiC polytype. In the energy range up to 1.5 eV above the top of the SiC valence band, interface states were found. Their electron spectrum is similar to that of sp²‐bonded carbon clusters in diamond‐like a‐C:H films suggesting the presence of elemental carbon at the SiC/SiO₂ interfaces.