The drain-induced barrier lowering (DIBL) effect in 4H-SiC MESFETs has been studied using the physical drift and diffusion model. Our simulation results showed that the high drain voltage typically applied in short-channel 4H-SiC MESFETs could substantially reduce the channel barrier and result in large threshold voltage shift. It is also found that the DIBL effect is more dependent on the ratio of the gate length to channel thickness (Lg/a), rather than the channel thickness itself. In order to minimize the DIBL effect, the ratio of Lg/a should be kept greater than 3 for practical 4H-SiC MESFETs.

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