Influence of AlGaN back-barrier on irradiation tolerance of AlGaN/AlN/GaN HEMTs

•We model the effect of AlGaN back-barrier on irradiation tolerance of AlGaN/AlN/GaN.•The 2DEG mobility and density before and after proton irradiation are calculated.•The mechanism AlGaN back-barrier impairs the irradiation tolerance is discussed. The introduction of AlGaN back-barrier increases the confinement of the two-dimensional electrons and further improves the high-frequency performance of AlGaN/AlN/GaN HEMTs. We investigate the effect of AlGaN back-barrier on irradiation tolerance of GaN-based HEMTs in terms of 2DEG density and electron scattering. The Schroödinger-Poisson equations are solved using a self-consistency method to calculate the conduction energy band and 2DEG density, which takes into account the Ga vacancies caused by proton irradiation. The electron scattering depending on phonons, ionized impurities, dislocations, and the interface AlN/GaN interface roughness is also studied, and 2DEG mobility is calculated for GaN-based HEMTs with and without back-barrier. The calculation results show that, after the same proton irradiation, the 2DEG density and mobility in GaN-based HEMT with back-barrier decrease more dramatically than that without back-barrier. The results may give some suggestions to those designing the radiation-resistant GaN-based HEMTs.