The leakage current degradation, single-event burnout (SEB), and single-event gate rupture (SEGR) behaviors induced by the heavy-ion irradiation in p-Channel and n-Channel power U-shaped metal–oxide–semiconductor field-effect transistors (UMOSFETs) are comparatively investigated in this article via experiments and simulations. The SEB and SEGR performances of a commercially available −100-V-rated p-Channel UMOSFET are tested under heavy-ion irradiation. The experimental results show that the sample devices can be prevented from the drain leakage current or gate leakage current degradation under the bias conditions of $V_{\mathrm {GS}} = -100$ V and $V_{\mathrm {GS}} = 0$ . However, a severe gate leakage current degradation can occur at $V_{\mathrm {DS}} = -100$ V when $V_{\mathrm {GS}} \ge 5$ V. In addition, the SEB and SEGR characteristics of a 100-V-rated n-Channel UMOSFET are obtained by simulations. The simulation results indicate that a p-Channel UMOSFET can achieve much better robustness against heavy ions compared with an n-Channel UMOSFET. Further, the leakage current degradation and failure mechanisms induced by heavy-ion irradiation are investigated via simulations. Finally, an effective method, which enlarges the width and depth of the source contact trench, is introduced to enhance the SEB tolerance of an n-Channel UMOSFET. The simulation result shows that the SEB threshold voltage can represent an increase of 23.1% with the hardening method.

In this article, the performance and triggering mechanism of the single-event burnout (SEB) of a 4H-SiC trench-gate (TG) MOSFET structure are evaluated by the 2-D numerical simulations. The novel N⁺ island buffer 4H-SiC TG MOSFET and the conventional TG 4H-SiC MOSFET are analyzed and compared to examine whether an N⁺ island region introduced in the second buffer can effectively reduce the impact ionization located at the N⁻ drift/N⁺ buffer junction and improve device tolerance to the SEB. The TCAD simulation results revealed that compared with the conventional structure, which is a simple double-buffer structure, the N⁺ island buffer-hardened structure changed the burnout threshold voltage, improving the SEB performance significantly. In addition, the results proved that the impact ionization played an important role in the SEB triggering mechanism, significantly affecting the SEB performance of the 4H-SiC TG MOSFET. The performance of the hardened N⁺ island buffer with a different dopant concentration of N-buffer 2 and a size of N⁺ island is discussed. The specific burnout threshold voltage at the optimal parameters of the proposed structure is 47% higher than that of the conventional structure.

In this paper, we propose an enhanced efficiency 4H-SiC U-shaped trench-gate MOSFET (UMOSFET) structure. The proposed device structure takes an advantage of a p ⁺ -polySi/SiC shielded region to reduce the on-state specific resistance. We show that the heterojunction diode formed by the p ⁺ -polySi and the n-drift regions improves the body diode effect, and thereby, reduces the reverse recovery charge. Further, we illustrate through simulation results that in comparison with the traditional p ⁺ -SiC shielded UMOSFET, the proposed device structure provides a 56.5% improvement in the figure of merit (including the breakdown voltage and on-resistance), and a 35.7% and 55.5% reduction in specific on-resistance and reverse recovery charge, respectively.

In this article, we investigate a new hardened GaN MISFET with an integrated Schottky contact (SC-MISFET). The new device architecture significantly improves the single-event burnout (SEB) characteristics. Compared to the field plate conventional GaN MISFET (FPC-MISFET), the Schottky metal can extract a larger number of holes, which are generated by heavy-ion irradiation. In addition, the number of carriers involved in the impact ionization process is substantially reduced. These features enable the new hardened structure to achieve a better overall SEB characteristic. After heavy-ion irradiation, the SEB threshold voltages of devices with conventional and hardened structures are 520 and 710 V, respectively.

A 1200-V rated CoolSiC Trench MOSFET structure has excellent overall electrical characteristics due to its unique asymmetric structure. However, it is sensitive to space heavy ion radiation. In this study, heavy ion irradiation experiments were conducted on 1.2 kV CoolSiC Trench MOSFET devices to calibrate the simulation structure model and critical failure conditions. The 2-D numerical simulator SILVACO TCAD was used to investigate the single event burnout (SEB) hardening method for the 1.2 kV-rated CoolSiC Trench MOSFET under high linear energy transfer (LET) values. The simulation results show that the improved CoolSiC Trench MOSFET structure can effectively enhance the SEB capability of the device without sacrificing its excellent overall electrical characteristics compared to the traditional CoolSiC Trench MOSFET. At 360 V voltage and 0.5 pC/ $\mu $ m LET value, the highest temperature is reduced from 3097 to 1502 K, and the lowest burnout threshold is increased by 200 V in the improved structure while maintaining almost unchanged characteristics at other locations.