Chao Peng

Hydrogen-terminated diamond field-effect transistors (H-diamond FETs) are promising for space electronics because of their high breakdown field, thermal stability, and radiation tolerance. However, their response to proton irradiation and the associated degradation mechanisms remain insufficiently understood. Here, depletion-mode H-diamond FETs are irradiated with 5 MeV protons at fluences of 1 × 1011, 1 × 1012, and 1 × 1013 p/cm2. At the highest fluence, the on-state current evaluated at a fixed gate overdrive decreases by approximately 43%, the peak transconductance decreases from 7.74 to 2.77 mS/mm, the subthreshold swing increases from 300 to 960 mV/dec, the gate leakage current increases by approximately four orders of magnitude, and the 99% current-stabilization time increases from 0.84 to 4.56 ms. Capacitance–voltage measurements reveal a positive flatband voltage shift consistent with radiation-induced negative trapped charge. Gate-controlled deep-level transient spectroscopy identifies three hole trap states at ET − EV = 0.354, 0.462, and 0.662 eV, including two states that emerge after irradiation and one preexisting state enhanced by irradiation. These results support two coupled degradation pathways: gate-stack ionization damage primarily affects threshold voltage, leakage, subthreshold behavior, and carrier stabilization, whereas displacement-related defects in diamond are associated with mobility and transconductance degradation.

Hydrogen-terminated diamond field-effect transistors (H-diamond FETs) are promising for radiation-tolerant electronics, but the response of the Al2O3/H-diamond gate stack to swift heavy ions remains insufficiently understood. Here, H-diamond FETs were irradiated with 1260 MeV Kr+ ions at fluences ranging from 1 × 106 to 1 × 108 ions/cm2 under different gate-bias conditions. DC, gate leakage, C–V, transient, and deep-level transient spectroscopy (DLTS) measurements were performed to evaluate device degradation. As the fluence increased, the threshold-voltage shift (ΔVth) increased from 2.50 ± 0.17 to 11.50 ± 0.51 V, while the relative transconductance reduction increased from 19.51% ± 1.12% to 65.16% ± 0.60%. At 1 × 108 ions/cm2, the subthreshold swing increased from approximately 0.240 to 0.400 ± 0.014 V/dec, and the 90% rise time increased from 0.24 to 0.44 ms. Degradation was more pronounced under positive gate bias during irradiation, suggesting field-assisted charge trapping. The increased gate leakage, C–V distortion, and 3.7-fold enhancement of the DLTS signal are consistent with irradiation-induced trapped charge and electrically active defects in the gate stack. These results identify gate-dielectric charge stability and Al2O3/H-diamond interface quality as key targets for radiation hardening.

We report a two-regime degradation behavior in NiO/β-Ga2O3 heterojunction diodes subjected to 1864 MeV Ta swift heavy ions (linear energy transfer in Si ≈ 75 MeV cm2/mg) over a fluence range from 1 × 108 to 1 × 1011 ions/cm2. At low fluences (≤1 × 109 ions/cm2), the devices retain rectification while exhibiting reduced forward current density (JF), increased specific on-resistance (Ron,sp), and enhanced reverse leakage current (JR), consistent with donor compensation in the β-Ga2O3 drift layer. Capacitance–voltage (C–V) analysis reveals a monotonic reduction in the net carrier concentration (Nnet) with carrier-removal rates (Rc) on the order of 107 cm−1, indicating a quasi-linear compensation regime. When the fluence approaches 1 × 1010 ions/cm2, rectification collapses and normal turn-on behavior is lost. The capacitance becomes weakly voltage dependent, suggesting deviation from linear compensation. Cross-sectional scanning transmission electron microscopy reveals densely distributed nanoscale latent tracks in the drift layer, while cross-sectional scanning electron microscopy shows pronounced ∼2 μm interfacial warping near the NiO/β-Ga2O3 junction. These results indicate a transition from a low-fluence quasi-linear carrier-compensation regime to a high-fluence failure regime associated with structural instability, where severe carrier compensation and failure-associated structural perturbations are both observed.

This study investigates the mechanism of single-event burnout (SEB) in NiO/β-Ga2O3 heterojunction diode (HJD) induced by atmospheric neutron. The degradation mode and physical mechanism are evaluated through current–voltage (I–V) measurement, emission microscopy, technology computer-aided design (TCAD), focused ion beam (FIB), and scanning electron microscopy (SEM) analysis. The experimental results indicate that the reverse bias voltage is a critical factor influencing SEB failure of NiO/β-Ga2O3 HJD. SEB occurs when the reverse bias reaches 750 V, characterized by a sharp increase in cathode current and catastrophic failure. Electrical characterization after SEB shows complete loss of rectifying behavior and reverse voltage withstand capability. TCAD simulations indicate that secondary particles generated by neutron interactions produce electron–hole pairs along their trajectory, which accelerate under the strong electric field in the drift layer, triggering impact ionization and current surge. Intense impact ionization leads to lattice temperature exceeding the melting point of β-Ga2O3, causing thermal runaway and burnout. FIB and SEM analysis confirms melt voids spanning the entire drift layer and part of the substrate, consistent with simulation results. These findings clarify the SEB mode and mechanism in NiO/β-Ga2O3 HJD and provide insights for evaluating their performance in harsh radiation environments.

This study investigates single-event burnout (SEB) effects in β-Ga2O3 Schottky barrier diodes under heavy ion irradiation. Bi, Ta, and Kr ions with linear energy transfer (LET) values of 99.7, 75, and 37 MeV/(mg·cm2), respectively, were used in the experiments. The results show that the SEB threshold voltage decreases with increasing LET, indicating a strong dependence on energy deposition. In addition, reverse bias is identified as a critical triggering condition for SEB, which occurs only when the applied voltage is high enough to initiate thermal runaway and cause irreversible damage. To further elucidate the failure mechanism, Kr ions were selected for detailed investigation. technology computer-aided design simulations combined with scanning electron microscopy-based failure analysis revealed that transient current surges can rapidly elevate the local temperature. Once the temperature reaches the melting point of Ga2O3 material, SEB is triggered by irreversible thermal failure. Moreover, the failure sites were primarily located at the edge of the Schottky junction, indicating structural vulnerability in this region. These findings clarify the LET and reverse bias dependence of SEB in ultra-wide bandgap devices and provide insights into radiation-hardened design.

This paper investigates the single-event burnout (SEB) effect of β-Ga2O3 Schottky barrier diode (SBD) under atmospheric neutron irradiation, including the degradation modes and physical mechanisms. The experimental results indicate that the reverse bias voltage (UR) is a critical factor influencing SEB failure of β-Ga2O3 SBD devices. When UR reaches 600 V, SEB failure occurs, characterized as a sudden loss of voltage-blocking capability during atmospheric neutron irradiation. The Emission Microscope and Scanning Electron Microscopy analysis reveal that SEB events occur at the edge of the Schottky junction, with the damaged area forming an approximately elliptical molten “void.” Geant 4 and TCAD simulation results show that the incidence of secondary ions, such as Cr, causes a rise in the lattice temperature inside the device, with the maximum lattice temperature increasing as UR increases. When UR is sufficiently high, the local lattice temperature reaches the melting point of the Ga2O3 material, ultimately leading to SEB failure. This study provides valuable theoretical support for Ga2O3-based power devices in aerospace applications.

In this work, we study the electrical performance of AlGaN/GaN high-electron-mobility transistors following irradiation with 14 MeV neutrons at fluences of 3 × 1012, 7.4 × 1012, 1.2 × 1013, and 1.0 × 1014 n/cm2. The results reveal that at a neutron fluence of 7.4 × 1012 n/cm2, there is a notable increase in the saturation drain current, a negative shift in threshold voltage, and an enhancement in peak transconductance. As the fluence continues to increase, the electrical characteristics of the device begin to deteriorate. However, at a fluence of 1.0 × 1014 n/cm2, the electrical performance is still better than that before irradiation. The defect evolution induced by neutron irradiation is studied by utilizing low-frequency noise (LFN) and deep-level transient spectroscopy (DLTS) techniques. LFN analysis shows only slight changes in interface state density, while DLTS results reveal a significant reduction in deep-level defects after irradiation. We speculate that bulk defects in the GaN or AlGaN layers predominantly influence device performance variations. Neutron irradiation facilitates the recombination of original defects, thereby decreasing the concentration of deep-level defects in the device. This decrease in deep-level defects alleviates carrier trapping by defects, resulting in an increased carrier concentration and improved electrical performance of the device.

This article investigates the single event effects (SEEs) of SiC power MOSFETs by laser irradiation. The single event burnout (SEB) and leakage current increase phenomenon are observed under pulsed laser two-photon absorption (TPA) conditions. The energy threshold for SEE corresponding to different bias voltages is obtained. An improved equivalent linear energy transfer (ELET) model is proposed to correlate the laser-induced SEE and the heavy-ion-induced SEE in SiC MOSFETs. Experimental results show that when laser energy exceeds 42 nJ, the error between the ELET values from the improved model and linear energy transfer (LET) from heavy-ion experiments is as low as 5%, significantly enhancing the accuracy of laser evaluation.