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

The shallow interface trap density near the conduction band in silicon carbide (SiC) metal-oxide-semiconductor (MOS) structure was evaluated by making capacitance-voltage measurements with gate-controlled-diode configuration using the n-channel MOS field 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 SiC MOSFETs is the high density of shallow traps between the conduction band edge and the surface Fermi level at the threshold. (C) 2002 American Institute of Physics.