Valence band structure and band offset of 3C- and 4H-SiC studied by ballistic hole emission microscopy

Abstract

p-type Schottky barriers in Pt/3C-SiC contacts have been measured using ballistic hole emission microscopy (BHEM) and estimated to be ∼0.06 eV higher than identically prepared Pt/p-type 4H-SiC contacts. This indicates the 3C-SiC valence band maximum (VBM) is ∼0.06 eV below the 4H-SiC VBM, consistent with the calculated ∼0.05 eV type-II valence band offset between these polytypes. We also observe no evidence of an additional VBM in 3C-SiC, which supports the proposal that the second VBM observed in BHEM spectra on 4H-SiC is a crystal-field split VBM located ∼110 meV below the highest VBM.