Influences of pre-oxidation nitrogen implantation and post-oxidation annealing on channel mobility of 4H-SiC MOSFETs

•Values of μFE for SiC DMODFETs are increased by increasing with the temperature and time for post-oxidation annealing.•SiC DMODFETs with nitrogen implantation in active region achieved higher values of μFE.•Values of IDS increased significantly with more nitrogen implantation energy attributed to the changing of counter doping in the DMOSFET p-well. Detailed investigations on the pre-oxidation nitrogen implantation and post-oxidation annealing processes for the improvement of channel mobility and specific on-resistance in 4H-SiC MOSFETs are reported. The results indicate that higher temperature and time for NO nitridation annealing process lead to higher field-effect channel mobility and lower specific on-resistance attributed to the good interface properties of SiC and SiO2 of MOSFETs. Furthermore, more nitrogen implantation energy and dose improved the channel mobility and specific on-resistance due to higher Id and less fixed charge, traps, and defects at the SiO2/SiC interface. The threshold voltages and blocking performance of MOSFETs are influenced by pre-oxidation nitrogen implantation conditions attributed to changing of counter doping mechanism in the DMOSFET p-well.