Neutron Irradiation Impact on AlGaN/GaN HEMT Switching Transients

Abstract

Current transient spectroscopy (CTS), was used to measure the impact of neutron irradiation on output currentlimiting charge traps in AlGaN/GaN HEMTs with time constants from 10 ms to 1800 s. We find that coupling between discrete traps was apparent, in contrast to the commonly employed assumption of independent trap (dis)charging, and increased after 14 MeV neutron irradiation of 2 × 10 13 n/cm 2 and above. Irradiation to a high dose of as much as 7.8 × 10 14 n/cm 2 , which is comparable to eight years exposure to a harsh radiation environment such as the ITER neutral beam injector prototype, increased trapped charge density, and reduced transient drain current to as little as 75% of its equilibrium value. These changes are consistent with displacement damage estimates based on radiation transport calculations.

Neutron Displacement Damage Cross Section in GaN: Numerical Evaluations and Differences With Si

“…The results for the TRIM function are slightly different: they are below for energies under MeV and above otherwise. At low energies, one would think that the different threshold energy assumptions would induce differences, but the 14 N(n,p) 14 C reaction predominates the other reactions on the lower energy range. The importance of the large neutron cross section from the N14(n,p) reaction was recently reflected in observed Single Event Effects in SRAMs [45] and is seen again in this analysis.…”

Characterization of traps in GaN-based HEMTs by drain voltage transient and capacitance deep-level transient spectroscopy

“…It can be noticed that the voltage transients in figure 2(b) gradually decreased to a steady state as time increased and can be explained as follows. In the off-state operation, the electrons from the gate can be trapped in the AlGaN barrier or GaN buffer due to the electric field distributed in the depletion region [7,[30][31][32]. When the gate voltage switched to 0 V, the captured electrons get detrapped and enable the recovery of the two-dimensional electron gas (2DEG) density [9,10], and thus the transient drain voltage gradually decreased under a constant drain current in figure 2(b) [21].…”

Research on the Synergistic Effect of Total Ionization and Displacement Dose in GaN HEMT Using Neutron and Gamma-Ray Irradiation

“…As the representative of the wide bandgap semiconductor devices, the gallium nitride high-electron-mobility transistor (GaN HEMT) has excellent electrical performance, hightemperature resistance, high power, and resistance to extreme radiation environments, which could meet the needs of new-generation spacecraft energy systems [1][2][3][4]. When a nuclear-powered spacecraft works in space, in addition to radiation damage caused by energetic particles, the comprehensive radiation environment with neutrons and gamma rays could also lead to performance degradation or even device failure of electronic systems by displacement damage effects (DDD) and total dose effects (TID) [5][6][7][8][9]. According to the reports [10,11], at a distance of 5.3 m from the 461 MW nuclear reactor core, normalized by the power, the neutron flux with an energy greater than 3 MeV is 2.13 × 10 8 n•cm −2 •s −1 •MW and an energy smaller than 0.4 MeV is 9.84 × 10 8 n•cm −2 •s −1 •MW.…”