Superior Characteristics of Body Diode in DMOSFET Fabricated on 4H-SiC Bonded Substrate

A novel substrate of 4H-SiC bonded substrate is expected to solve issues such as decreasing the on-resistance, which has attracted much attention. Therefore, several studies have been conducted on the use of bonded substrates. In this study, we fabricated a DMOSFET on a bonded substrate and compared its static and dynamic characteristics with those on a single-crystal substrate. Consequently, the on-resistance of the DMOSFET fabricated on a bonded substrate was lower than that on a single-crystal substrate owing to the low resistivity of the polycrystalline substrate. Also, reverse recovery loss of the DMOSFET fabricated on a bonded substrate was lower than that on single-crystal substrate at high temperature due to low carrier lifetime in a drift layer. Additionally, we observed that the DMOSFET fabricated on a bonded substrate did not generate bipolar degradation despite the application of a forward-current stress of over 1500 A cm - 2 . According to these results, we expected that the carrier lifetime in both drift layer and transfer layer was decreased on a bonded substrate.