Comprehensive trade-off strategy for SiC MOSFETs using buried-MOS configuration

Abstract

While silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) have entered commercial markets, they still rely on specialized device structural approaches tailored to meet specific application demands. The intricate and interdependent relationships among diverse physical parameters of SiC MOSFETs have not been fully elucidated to address the trade-offs that influence each other. This study aims to clarify these complex relationships and propose a well-balanced trade-off strategy. The proposed buried-MOS configuration ensures a harmonious balance among lower R_on,sp, reduced C_GD, and milder E_OX without compromising breakdown voltage (BV), thereby optimizing the interconnected physical parameters of SiC devices and significantly enhancing their high-voltage, high-frequency performance and reliability. The experimental results quantitatively demonstrate the advantages of the buried-MOS structure: high-frequency figure of merit high-frequency figure of merit (HF-FOM) (R_DS,on × C_GD) by 2.5×, HF-FOM (R_DS,on × Q_GD) by 2.2× and Baliga figure of merit (BFOM = 4BV²/R_on,sp) by 1.7× compared with the conventional BOX-MOS. Importantly, this approach embodies both theoretical significance and practical applicability, which is compatible with the existing large-scale manufacturing processes and requires no additional steps.