An　annealing　process　at　120°C　with　supercritical　fluid　(SCF)　is　proved　to　be　highly　efficient　in　improving　the　quality　4H-SiC/SiO2　in　MOSFET　devices.　The　peak　field-effect　mobility　of　the　fabricated　lateral　4H-SiC　MOSFET　on　(0001)　Si　face　was　improved　to　72.3　cm2/V.　s,　which　is　about　twice　as　much　as　the　state-of-the-art　results　of　post　oxidation　annealing　process　in　the　mostly　used　nitrogen-oxide　atmosphere.　The　low　temperature　avoids　the　re-oxidation　and　material　decomposing　issues　of　high　temperature.　As　a　result,　the　reliability　of　the　dielectric　layer　is　significantly　enhanced.　What＇s　inspiring　is　that　the　proposed　efficient　low　temperature　annealing　process　is　compatible　with　the　standard　4H-SiC　MOSFET　fabrication　process.　©　2021　IEEE.