Counter-doped MOSFETs of 4H-SiC

In this paper, we investigate the effect of counter-doping of nitrogen at the channel region of epitaxial n-channel 4H-SiC MOSFETs on the channel mobility and the threshold voltage. From this study, we have found that the channel mobility steeply improves as the nitrogen dose increases. At a dose of 2/spl times/ or 2.5/spl times/10/sup 12/ cm/sup -2/ the enhancement MOSFET has achieved an effective channel mobility of 20 cm/sup 2//Vs or a field effect mobility of 38 cm/sup 2//Vs at a peak.