Correlation between channel mobility and shallow interface traps in SiC metal–oxide–semiconductor field-effect transistors

Abstract
The shallow interface trap density near the conduction band in siliconcarbide(SiC) metal–oxide–semiconductor (MOS)structure was evaluated by making capacitance–voltage measurements with gate-controlled-diode configuration using the n-channel MOSfield effect transistors(MOSFETs). The close correlation between the channel mobility and the shallow interface trap density was clearly found for the 4H- and 6H-SiC MOSFETs prepared with various gate-oxidation procedures. This result is strong evidence that a significant cause of the poor inversion channel mobility of SiCMOSFETs is the high density of shallow traps between the conduction band edge and the surface Fermi level at the threshold.