Effects of radiation damage in gan and related materials

Due to their relatively high average bond strengths, GaN and related materials are inherently radiation hard when compared to the more conventional Si and GaAs. For example, experimental evidence suggests that GaN is several orders of magnitude more resistant to radiation damage than GaAs, ie. it can withstand radiation doses at least two orders of magnitude higher than those degrading GaAs of similar doping level. We review the literature on different types of ionizing radiation on GaN, InGaN and AlGaN materials and devices, including high electron mobility transistors and light-emitting diodes. A comparison of theoretical and experimental threshold displacement energies is given, along with a summary of energy levels introduced by different forms of radiation, carrier removal rates and role of existing defects. In terms of heterostructures, experimental data shows the radiation hardness decreases in the order AlN/GaN >AlGaN/GaN > InAlN/GaN, consistent with the average bond strengths in the Al-based materials. Future areas for research are identified, including the strong asymmetry in carrier removal rates in n- and p-type GaN and the interaction of radiation defects in doped nitrides with the high dislocation in this material.