Forward bias annealing of proton radiation damage in NiO/Ga2O3 rectifiers

17 MeV proton irradiation at fluences from 3–7 × 1013 cm−2 of vertical geometry NiO/β-Ga2O3 heterojunction rectifiers produced carrier removal rates in the range 120–150 cm−1 in the drift region. The forward current density decreased by up to 2 orders of magnitude for the highest fluence, while the reverse leakage current increased by a factor of ∼20. Low-temperature annealing methods are of interest for mitigating radiation damage in such devices where thermal annealing is not feasible at the temperatures needed to remove defects. While thermal annealing has previously been shown to produce a limited recovery of the damage under these conditions, athermal annealing by minority carrier injection from NiO into the Ga2O3 has not previously been attempted. Forward bias annealing produced an increase in forward current and a partial recovery of the proton-induced damage. Since the minority carrier diffusion length is 150–200 nm in proton irradiated Ga2O3, recombination-enhanced annealing of point defects cannot be the mechanism for this recovery, and we suggest that electron wind force annealing occurs.

在垂直结构的NiO/β - Ga₂O₃异质结整流器中，当注量为3 - 7×10¹³ cm⁻²的17 MeV质子辐照时，在漂移区产生的载流子去除率在120 - 150 cm⁻¹范围内。对于最高注量，正向电流密度最多降低了2个数量级，而反向泄漏电流增加了约20倍。在需要去除缺陷的温度下热退火不可行的此类器件中，低温退火方法对于减轻辐射损伤具有重要意义。虽然之前已表明在这些条件下热退火对损伤的恢复有限，但之前尚未尝试过通过从NiO向Ga₂O₃注入少数载流子进行非热退火。正向偏压退火使正向电流增加，并使质子诱导的损伤得到部分恢复。由于在质子辐照的Ga₂O₃中少数载流子扩散长度为150 - 200 nm，点缺陷的复合增强退火不可能是这种恢复的机制，我们认为发生了电子风力退火。