An Improved 4H-SiC Trench Gate MOSFETs Structure with Low On-Resistance and Reduced Gate Charge

In this paper, an improved 4H-SiC trench-gate metal-oxide-semiconductor field effect transistors (UMOSFETs) structure with low on-resistance and reduced gate charge is proposed. The added n-type region in the improved structure reduces on-resistance of the device significantly while maintaining same breakdown voltage. The gate of the improved structure is designed as a p-n junction to reduce the gate-charge. The specific on-resistances of the improved 4H-SiC UMOSFETs is 1.87 mΩ.cm2 at VGS=18 V and VDS=10 V, compared with 4.48 mΩ.cm2 for the conventional p+ shielding UMOSFETs structure with same breakdown voltage. The on-resistance and figure of merit (FOM = VBR2/Ron) improve by 58.3% and 103.6%, respectively. Compared with the conventional structure, the results show that gate-drain charge of the improved structure can be improved by 23.8%.