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 diff erent oxidation procedures, source/drain implant species and implant activa tion temperature. The fixed oxide charge and the field-effect mobility in t he inversion layer have been extracted, with best values of 1.8 x 10(12) cm (-2) and 14 cm(2) N-s, respectively. The interface state density, D-it clos e to the conduction band of 4H-SiC has been extracted from the subthreshold drain characteristics of the MOSFETs. A comparison of interface state dens ity, 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/SiO2 interface quality.