1200V 4H-SiC MOSFET with a High-K Source Gate for Improving Third-Quadrant and High Frequency Figure of Merit Performance

TL;DR

A new 1200V 4H-SiC MOSFET design improves performance in high-frequency power applications by reducing voltage and capacitance.

Contribution

A novel High-K source-gate structure is introduced to enhance third-quadrant and high-frequency performance in SiC MOSFETs.

Findings

The reverse conduction voltage is reduced from 2.79 V to 1.53 V with the new structure.

The gate-to-drain capacitance is reduced by incorporating a shielding area in the design.

HF-FOM metrics Cgd × Ron,sp and Qgd × Ron,sp are decreased by 48.1% and 58.9%, respectively.

Abstract

This paper proposes a 1200V 4H-SiC MOSFET incorporating a High-K dielectric-integrated fused source-gate (HKSG) structure, engineered to concurrently enhance the third-quadrant operation and high-frequency figure of merit (HF-FOM). The High-K dielectric enhances the electric field effect, reducing the threshold voltage of the source-gate. As a result, the reverse conduction voltage drops from 2.79 V (body diode) to 1.53 V, and the bipolar degradation is eliminated. Moreover, by incorporating a shielding area within the merged source-gate architecture, the gate-to-drain capacitance Cgd of the HKSG-MOS is reduced. The simulation results show that the HF-FOM Cgd × Ron,sp and Qgd × Ron,sp of the HKSG-MOS are decreased by 48.1% and 58.9%, respectively, compared with that of conventional SiC MOSFET. The improved performances make the proposed SiC MOSFEET have great potential in high-frequency power applications.

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