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-pO2) ambient is effective in reducing the interface state density (DIT) at a SiC (0001)/SiO2 interface near the conduction band edge (EC) of SiC. The DIT value at EC − 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-pO2 annealing does not degrade the oxide dielectric property (breakdown field ∼10.4 MV cm−1).