Proton irradiation impact on interface traps under Schottky contact in AlGaN/GaN heterostructure

The effect of 3 MeV proton irradiation on interface traps under a Schottky contact in an AlGaN/GaN heterostructure has been investigated in this work. Utilizing the frequency-dependent conductance technique, the detailed information about interface traps under different proton doses has been evaluated. When the proton irradiation dose is increased to 5 × 1014 H+/cm2, it is observed that the deepest energy level of interface traps changes from 0.375 eV to 0.346 eV and the shallowest energy level changes from 0.284 eV to 0.238 eV. The corresponding energy range expands from 0.091 eV to 0.108 eV. Especially, the trap density at the deepest energy level and that at the shallowest energy level are reduced by 65% and 93%, respectively. Transmission electron microscopy and energy dispersive x-ray spectroscopy are also used to assess the Schottky contact interface, and no element inter-diffusion is observed after proton irradiation. The reverse gate leakage current decreases with an increase in the proton irradiation dose, which agrees with the reduction in interface trap density.