Nano-Scale Native Oxide on 6H-SiC Surface and its Effect on the Ni/Native Oxide/SiC Interface Band Bending

Abstract

Native oxide layer with thickness of about 1 nm was found easy to form on 6H-SiC surface during transporting from cleaning process to vacuum chambers, which was examined by x-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). The interface band bending was studied by synchrotron radiation photoelectron spectroscopy (SRPES). For the native-oxide/SiC surface, after Ni deposition, the binding energy of Si 2p red-shifted about 0.34 eV, which suggested the upward bending of the interface energy band. Therefore, the native oxide layer should be considered on the study of SiC devices because it may affect the electron transport properties significantly.

Analysis of Thin Thermal Oxides on (0001) SiC Epitaxial Layers

“…Note that although the formation of a native oxide layer of up to 10 Å has been observed after a wet cleaning process [4], we did not find any indication of native oxide after our cleaning step neither by XPS nor CV measurements. Current-voltage (IV) measurements were conducted to determine the leakage current through the oxides.…”