Single event burnout (SEB) of enhancement mode GaN high-electron mobility transistors (HEMTs) under heavy ion irradiation is systematically studied based on simulations in this work. Susceptibility to SEB of different particle incidence environments is investigated to determine the device's sensitive position. Under these conditions, the mechanism of SEB in enhancement mode HEMTs is mainly associated with the charge congestion and subsequent continuous impact ionization. A hardened HEMT structure with the gate and drain double field plates is proposed correspondingly. Apart from better output characteristics and almost 25% improvement of breakdown voltage, the hardened structure also demonstrates better tolerance of SEB. This hardened structure can modify the electric field in the high field region so that charge accumulation is reduced significantly, thus effectively decreasing the possibility of SEB's occurrence. With a vertical heavy ion strike of 63.8 MeV ·cm ² /mg linear energy transfer (LET), SEB threshold voltage of the conventional structure HEMT is 160 V, while that of the hardened structure HEMT is much higher, reaching 249 V. Besides, the hardened device exhibits better SEB tolerance than the conventional device even at different higher LET conditions. Furthermore, the contribution to SEB tolerance of each field plate is also discussed.

A comprehensive study of proton irradiation reliability on a bilayer dielectrics SiN_x/Al₂O₃ MIS-HEMT, the common Schottky gate HEMT, and a single dielectric layer MIS-HEMT with SiN_x and with Al₂O₃ for comparison is conducted in this paper. Combining the higher displacement threshold energy of Al₂O₃ with the better surface passivation of the SiN_x layer, the bilayer dielectrics MIS-HEMT presents much smaller degradation of structural materials and of device electrical performance after proton irradiation. Firstly, the least of the defects caused by irradiation suggesting the smallest structural material degradation is observed in the bilayer dielectrics MIS-HEMT through simulations. Then, DC and RF electrical performance of four kinds of devices before and after proton irradiation are studied through simulation and experiments. The smallest threshold voltage degradation rate, the smallest maximum on-current degradation and Gm degradation, the largest cut-off frequency, and the lowest cut-off frequency degradation are found in the bilayer dielectrics MIS-HEMT among four kinds of devices. The degradation results of both structural materials and electrical performance reveal that the bilayer dielectrics MIS-HEMT performs best after irradiation and had better radiation resilience.

This article reports a comprehensive investigation into the failure behavior and underlying mechanisms of a gallium nitride (GaN)-based low-noise amplifier (LNA) induced by high-power microwave (HPM) pulses. A dual-layer failure analysis framework (spanning system and device levels) is proposed to address a critical gap in existing literature: most studies focus on individual GaN high-electron-mobility transistors (HEMTs) rather than GaN-integrated LNAs under high-power electromagnetic stress. Moreover, the existing research progress on LNA reliability under HPM injection conditions is mostly about gallium arsenide (GaAs)-based LNA, such as GaAs heterojunction bipolar transistor (HBT) LNA. First, a custom-designed test system was employed to monitor the electrical performance of the GaN LNA while systematically stepped HPM pulses were injected, enabling the determination of the failure threshold. Second, the failure mechanism of the entire LNA was analyzed at the system level, and the primary failure cause of key components was identified. Obvious damage morphology was detected on one of the first-stage GaN HEMTs and a nearby resistor. Microscopic morphological analysis revealed that the GaN HEMT first undergoes breakdown, followed by a global current increase in the LNA, and ultimately the melting of the resistor—thus clarifying the cascading failure path: from HEMT breakdown to overall current rise, and finally to resistor melting. Finally, the failure mechanism on the transistor level was investigated. Via focused ion beam (FIB) etching and microscopic observation, it was found that the failure originates from electrothermally induced melting in two regions: the gate area near the HEMT input terminal and the region adjacent to the gate–source interface. Furthermore, simulations were conducted to investigate the evlution of internal electrical and thermal characteristics within the GaN HEMT. The simulation results demonstrate that the concentrated electric field and increased current density in the gate–source region lead to a rise in local lattice temperature—consistent with the damage morphology observed in experiments. These simulation results provide detailed insights into the internal evolution process of the failure and strongly support the aforementioned conclusions.