A study on turn-off, and on-resistance and short-circuit capability trade-off characteristics in 1.2 kV SiC MOSFETs

Abstract This paper presents experimental evaluations of the trade-off characteristics of the turn-off loss ( E OFF )—slew rate of the drain current density ( d J D / d t ) using the latest 1.2 kV SiC trench and planar metal-oxide-semiconductor field-effect-transistors (MOSFETs). It found that smaller reverse transfer capacitances ( C rss ) improved E OFF − d J D / d t . This was because of the moderately low doping density of the n-drift layer and the optimally designed gate structures. Experimental and numerical explorations were also conducted to identify structures that improve on-resistance ( R on,sp )—short-circuit capabilities (SCWT). The trench MOSFETs achieved suppressed peak drain current densities in the short-circuit state while keeping low R on,sp , indicating superior R on,sp —short-circuit withstanding time (SCWT) to planar MOSFETs. Furthermore, the trench MOSFETs with narrower and higher doping J-FET regions can improve the trade-off. In conclusion, trench MOSFETs with optimized J-FET regions exhibited superior R on,sp —SCWT trade-off characteristics while showing comparable E OFF − d J D / d t to planar MOSFETs.