Effect of postdeposition annealing on electrical properties of RF‐magnetron sputtered CeOx gate on 4H‐silicon carbide

Abstract

AbstractThis research investigated the electrical characteristics of CeOx thin films deposited on n‐type 4H‐SiC via RF‐magnetron sputtering technique. Postdeposition annealing of CeOx was performed at different annealing temperatures (400, 600, 800, and 1000 °C) for 30 min in an argon ambient. The thickness of the deposited CeOx ranging from 30 to 40 nm was measured by an ellipsometer. All annealed samples showed smooth surface morphology without any physical defects. In this work, the lowest root‐mean square surface roughness was detected at samples annealed at 1000 °C. Prior to electrical characterization, all annealed samples demonstrated a positive flat‐band voltage shift indicating that negative effective oxide charge was present in the oxide layer. The sample annealed at 1000 °C revealed the lowest effective oxide charge and interface trap density as compared with other samples. The calculated interface trap density and effective oxide charge from high‐frequency capacitance–voltage curve were correlated with leakage current density and electric breakdown field. The Fowler–Nordheim tunneling mechanism only occurred in the sample annealed at 1000 °C. The leakage current density and electric breakdown field were enhanced as the postdeposition annealing increased to 1000 °C as compared with other samples.