Low-temperature re-oxidation of near-interface defects and voltage stability in SiC MOS capacitors

Abstract

We proposed a solution to improve the interface property and voltage instability of silicon carbide metal–oxide–semiconductor (SiC MOS) capacitors by eliminating near-interface defects with a single oxygen element. Results indicated that the quality of the silicon dioxide (SiO2) film and SiC/SiO2 interface and the voltage stability of SiC MOS capacitors were simultaneously improved by the proposed process. The mechanism underlying the improvement in the electrical performance of SiC MOS capacitors by oxygen plasma re-oxidation annealing (OP-ROA) could be elaborated by analysing the results of secondary ion mass spectroscopy and X-ray photoelectron spectroscopy. We believe that the OP-ROA process can eliminate C- and Si-related defects and silicon oxycarbide (SiOxCy) and reduce the thicknesses of the interface–transition region, thereby decreasing relative Si and C contents near the SiC/SiO2 interface. The evolution of C-related defect structures was simulated through density functional theory calculation, which was performed as a supplemental analysis.