Improvement of the trade-off between Qrrand IDSSin trench field plate power MOSFETs by proton irradiation of the cathode side

Abstract

Reducing the reverse recovery charge (Qrr) in field plate (FP)-MOSFETs improves the power consumption of DC/DC converters. Although lifetime killer is used to reduce Qrr, this increases the off-leakage current. In this study, local lifetime killer in FP-MOSFET is first demonstrated by proton irradiation. A damage peak on the cathode side is found to have more advantages than anode damage and uniform damage. Both the Qrr-IDSS trade-off and the inherent dynamic avalanche in FP are successfully improved by cathode damage. Furthermore, a low surge voltage with soft recovery waveforms is achieved by cathode damage owing to internal FP snubber. Therefore, local lifetime killer on the cathode side has the potential to realize FP-MOSFETs with low power consumption, low noise, good reliability, and high-speed operation.