A Novel Solution to the Turn-On Recovery Problem of the Floating Island Device

The floating island (FI) structure is a promising technology for power semiconductor devices, as it can reduce device-specific ON-resistance significantly. However, the structure suffers from a severe turn-on recovery hysteresis problem. In this article, the mechanism of the FI's turn-on recovery problem is elucidated. A novel n+ buffer structure is proposed to solve the problem. A mixed mode simulation of the new structure in the double pulse circuit is conducted to validate their efficacy. The SiC FI junction barrier Schottky (JBS) diode with n+ buffer has successfully overcome the turn-on recovery problem that is observed in conventional FI JBS. The specific ON-resistance is recovered to a level that is significantly lower than the conventional JBS with the same breakdown voltage. A simple model is established to describe the effect of the n+ buffer. In the end, the fabrication process of the FI structure with n+ buffer is illustrated.