Fabrication and characterization of 4H-SiC planar MESFETs

The planar 4H-SiC MESFETs were fabricated by employing an ion-implantation process instead of a recess gate etching process, which is commonly adapted in compound semiconductor MESFETs, to eliminate potential damage to the gate region during etching process. Excellent ohmic and Schottky contact properties were achieved by using the modified RCA cleaning of 4H-SiC surface and the sacrificial thermal oxide layer. The fabricated MESFETs was also free from drain current instability, which the most of SiC MESFETs have been reported to suffer for the charge trapping. The drain current recovery characteristics were also improved by passivating the surface with a thermal oxide layer and eliminating the charge trapping at the surface. The performance of fabricated MESFETs was characterized by analyzing the small-signal equivalent circuit parameters extracted from the measured parameters.