Analytical and Structural Investigations of the Metal - Enhanced Oxidation of SiC - MOS Structures

摘要

The purpose of this work is to study the chemical and structural variations across the MEO SiO_2/4H-SiC interfaces in order to compare results with standard thermally oxidized and NO annealed samples, and correlate these process variations with the improved mobility of the SiC MOS devices. The MEO SiC-MOS structures were studied via X-ray Photo-Electron Spectroscopy (XPS), EELS and TEM. Both XPS and EELS analyses indicate that the major elements C, Si and O go through changes of their chemical states in the interface transition regions from SiC to SiO_2. Structural characterization with TEM reveal contrast changes at the near interface regions that indicate local chemical and/or stoichiometric variations, but no structural degradation or amorphization of the top few atomic SiC layers. XPS depth profile studies suggest that these changes have occurred up to ～ 200 nanometers deep down into the SiC substrate.