Micromachines (Jun 2021)

Investigation of 3.3 kV 4H-SiC DC-FSJ MOSFET Structures

  • Chia-Yuan Chen,
  • Yun-Kai Lai,
  • Kung-Yen Lee,
  • Chih-Fang Huang,
  • Shin-Yi Huang

DOI
https://doi.org/10.3390/mi12070756
Journal volume & issue
Vol. 12, no. 7
p. 756

Abstract

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This research proposes a novel 4H-SiC power device structure—different concentration floating superjunction MOSFET (DC-FSJ MOSFET). Through simulation via Synopsys Technology Computer Aided Design (TCAD) software, compared with the structural and static characteristics of the traditional vertical MOSFET, DC-FSJ MOSFET has a higher breakdown voltage (BV) and lower forward specific on-resistance (Ron,sp). The DC-FSJ MOSFET is formed by multiple epitaxial technology to create a floating P-type structure in the epitaxial layer. Then, a current spreading layer (CSL) is added to reduce the Ron,sp. The floating P-type structure depth, epitaxial layer concentration and thickness are optimized in this research. This structure can not only achieve a breakdown voltage over 3300 V, but also reduce Ron,sp. Under the same conditions, the Baliga Figure of Merit (BFOM) of DC-FSJ MOSFET increases by 27% compared with the traditional vertical MOSFET. Ron,sp is 25% less than that of the traditional vertical MOSFET.

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