4H-SiC MOSFETs With Borosilicate Glass Gate Dielectric and Antimony Counter-Doping

In this letter, it is demonstrated that 4H-SiC MOSFETs with borosilicate glass (BSG) as the gate dielectric result in significantly higher channel mobility than standard nitride oxide annealed devices, due to lower density of near-interfacial traps at the BSG/SiC interface. Using a thin Antimony-doped surface layer in conjunction with the BSG dielectric results in higher channel mobility at room temperature. The field-effect channel mobility of such devices is found to be 180 cm
²
/V · s at low transverse electric fields (close to threshold) and 94 cm
²
/V · s at high fields (~2 MV/cm), which is about a factor of five higher than the state-of-the-art. This, along with a tunable threshold voltage, could make this approach very attractive for power MOSFET applications. However, the poor bias temperature instability of BSG is a big challenge for utilization of this dielectric.