Reduction of interface state density in SiC (0001) MOS structures by low-oxygen-partial-pressure annealing

Abstract

We report that annealing in low-oxygen-partial-pressure (low-p O2) ambient is effective in reducing the interface state density (D IT) at a SiC (0001)/SiO2 interface near the conduction band edge (E C) of SiC. The D IT value at E C - 0.2 eV estimated by a high (1 MHz)-low method is 6.2 ×1012 eV-1 cm-2 in as-oxidized sample, which is reduced to 2.4 ×1012 eV-1 cm-2 by subsequent annealing in O2 (0.001%) at 1500 C, without interface nitridation. Although annealing in pure Ar induces leakage current in the oxide, low-p O2 annealing does not degrade the oxide dielectric property (breakdown field ∼10.4 MV cm-1).