Effect of processing conditions on inversion layer mobility and interface state density in 4H−SiC MOSFETs

N-channel, inversion mode MOSFETs have been fabricated on 4H−SiC using different oxidation procedures, source/drain implant species and implant activation temperature. The fixed oxide charge and the field-effect mobility in the inversion layer have been extracted, with best values of 1.8×10 12 cm −2 and 14 cm 2 /V-s, respectively. The interface state density, D it close to the conduction band of 4H−SiC has been extracted from the subthreshold drain characteristics of the MOSFETs. A comparison of interface state density, inversion layer mobility and fixed oxide charges between the different processes indicate that pull-out in wet ambient after reoxidation of gate oxide improves the 4H−SiC/SiO 2 interface quality.