High Performance 3.3KV 4H-SiC MOSFET with a Floating Island and Hetero Junction Diode

In this paper, a 3.3 kV 4H-SiC MOSFET structure with a floating island and a built-in heterojunction diode (FIHJD-MOSFET) is proposed, and analyzed by TCAD simulator. The floating island in the FIHJD-MOSFET not only improves the static performance of the device through charge balancing but also protects the P+ polysilicon region from a high electric field. Owing to this, the FIHJD-MOSFET operates stably even at high voltage, and the reverse recovery charge and the switching loss are also improved through the built-in heterojunction diode. As a result, B-FOM of FIHJD-MOSFET improved by 67.4 %, and reverse recovery charge and total switching loss were improved by 72.7 % and 66.4 % respectively, compared to conventional diffusion MOSFET (C-DMOSFET).