Degradation in AlGaN/GaN HEMTs irradiated with swift heavy ions: Role of latent tracks

摘要

AlGaN/GaN high electron mobility transistor (HEMT) devices were irradiated with swift heavy ions at different fluences. From structural and electrical studies, it was found that SHI irradiation leads to a significant deterioration of structural and electrical properties of the devices. Positive threshold voltage V-th was found to increase by about 85% as a result of irradiation with 1540-MeV Bi-209 ions at fluence of 1.7 x 10(11 )ions/cm(2), while this threshold voltage value was increased by 55% after irradiation with 2300-MeV Xe-129 at a fluence of 4 x 10(11) ions/cm(2). The maximum saturation drain current I-ds was decreased by about two orders of magnitude in the device after irradiation with Bi-209 ions. Quasi-continuous tracks were observed visually in the devices after irradiation with Bi-209 ions. The observed defects and disorders induced in the devices by SHI irradiation were found responsible for the decrease in carrier mobility and sheet carrier density, and finally, these defects resulted in the degradation of electrical characteristics of HEMTs.