Short-Channel Effects in SiC MOSFETs Based on Analyses of Saturation Drain Current

In this brief, the minimum channel length (the channel length at which short-channel effects (SCEs) begin to occur) in SiC MOSFETs was experimentally determined. We fabricated 4H-SiC MOSFETs with various channel lengths and acceptor concentrations and analyzed their electrical characteristics. We propose a method for determining the minimum channel length in silicon carbide (SiC) MOSFETs, focusing on the increased rate of the drain current in the saturation region, and define the minimum channel length for the fabricated SiC MOSFETs with various acceptor concentrations in the p-body region. The relationship between the minimum channel length and the acceptor concentration for these SiC MOSFETs shows a similar tendency to that for Si MOSFETs. The obtained minimum channel lengths in the SiC MOSFETs are slightly longer than those in Si MOSFETs, which is caused by the larger built-in potential of SiC compared to that of Si and the existence of a high density of interface states, which enhance the SCEs. This work provides guidelines for the design of SiC MOSFETs that utilize very short-channel structures.