Processing Issues for Reliable 4H-SiC MOSFET

This paper reports on some relevant processing issues for 4H-SiC MOSFETs. In particular, the work focuses on the behavior of gate oxide and channel mobility with respect to the post-deposition treatments performed to improve the electronic quality of the SiO2/SiC interface. A comparison between different treatments of the gate oxides in atmospheres containing nitrogen or phosphorus is reported, showing a nice correlation between the interface states density Dit and the channel mobility ?FE measured in lateral devices. In spite of the good mobility results obtained using POCl3, nitridation processes in N2O of the gate oxide shows a better reliability in terms of leakage current and flat band voltage stability. Finally, a comparison of the Ron vs VB performances of the available SiC MOSFETs with GaN HEMTs is reported.