Impact of post-nitridation annealing in CO2 ambient on threshold voltage stability in 4H-SiC metal-oxide-semiconductor field-effect transistors

Abstract

The combination of NO annealing and subsequent post-nitridation annealing (PNA) in CO2 ambient for SiO2/SiC structures has been demonstrated to be effective in obtaining both high channel mobility and superior threshold voltage stability in SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs). N atoms on the SiO2 side of the SiO2/SiC interface incorporated by NO annealing, which are plausible causes of charge trapping sites, could be selectively removed by CO2-PNA at 1300 °C without oxidizing the SiC. CO2-PNA was also effective in compensating oxygen vacancies in SiO2, resulting in high immunity against both positive and negative bias-temperature stresses.