Comparison of Interface State Density Characterization Methods for SiO[sub 2]/4H-SiC MOS Diodes

Four different methods for calculating interface state density in vertical metal-oxide semiconductor (MOS) capacitors were employed on the same samples. The Terman, ac, quasi-static, and Hi-Lo methods were used to extract surface state densities from the interface. Surface state densities from to were obtained, depending on the method employed. The Hi-Lo method is particularly susceptible to underestimating the trap density if UV light is not used to empty all the deep-lying traps during measurement.