Improvement of charge trapping by hydrogen post-oxidation annealing in gate oxide of 4H–SiC metal–oxide–semiconductor capacitors

Abstract

The effect of hydrogen postoxidation annealing (POA) on the reliability of gate oxide formed in 4H–SiC metal–oxide–semiconductor (MOS) capacitors has been investigated. Argon POA at 1200 °C and hydrogen POA were carried out over a temperature range of 400–1000 °C to improve the properties of 4H–SiC/SiO2 interface and thermal gate oxide. Interface state density Dit decreases as the temperature of hydrogen POA increases and saturates at 800 °C. Additionally, the characteristics of charge trapping in gate oxide against the electron injection was greatly improved by the hydrogen POA above 800 °C. Hence, we can conclude that the hydrogen POA at high temperature is effective for improving the Dit and reliability of gate oxide formed in 4H–SiC MOS devices.