Study of the Wet Re-Oxidation Annealing of SiO_2/4H-SiC (0001) Interface Properties by AR-XPS Measurements

摘要

We have characterized the SiO_2/SiC system in terms of bonds and composition by angle-resolved X-ray photoelectron spectroscopy for two different oxidation processes: a standard oxidation, and a process which includes a re-oxidation step. Although the oxide is quite stoichiometric (Si~(4+) oxidation states) far away from the interface, the analyses revealed at the SiO_2/SiC boundary a complex transition layer containing "mixed" (Si-O-C) compounds. After the so-called re-oxidation procedure, we have observed a significant decrease (30%) of the Si bonds related to these (Si-O-C) species. From these results, the improvement of the electrical properties of SiO_2/SiC interface during the re-oxidation can now be clearly related to the reduction of the carbon products.