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

摘要

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℃ and hydrogen POA were carried out over a temperature range of 400-1000℃ to improve the properties of 4H-SiC/SiO_(2) interface and thermal gate oxide. Interface state density D_(it) decreases as the temperature of hydrogen POA increases and saturates at 800℃. Additionally, the characteristics of charge trapping in gate oxide against the electron injection was greatly improved by the hydrogen POA above 800℃. Hence, we can conclude that the hydrogen POA at high temperature is effective for improving the D_(it) and reliability of gate oxide formed in 4H-SiC MOS devices.