Effect of hydrogen plasma treatment on the electrical properties for SiC-based power MOSFETs

Abstract

This study investigates the effects of hydrogen plasma treatment on the leakage current and capacitance characteristics of metal–insulator–semiconductor (MIS) structures on SiC substrate. The H2 plasma treatment resulted in improved breakdown voltage and reduced defect density (Nd) in an atomic-layer-deposited 30 nm-thick Al2O3 (top)/15 nm-thick SiO2 bi-layer dielectric. The breakdown voltage in Al2O3/SiO2 bi-layer dielectric after H2 plasma treatment was improved by about 6.2% (initial 47 V). The value of Nd decreased by about one order in the Al2O3/SiO2 bi-layer dielectric from 2.3 × 1011/cm2 to 3.4 × 1010/cm2 after H2 plasma treatment. Further, the interface trap density (Dit) of Al2O3/SiO2 bi-layer dielectrics was 1.4 × 1012 cm−2·eV−1, and 50% of that of the SiO2 single dielectric film.