Long-term reliability of gate-oxide in Cascode GaN power devices under proton irradiation with different energies

In this paper, the effects of proton irradiation with different energies on the long-term reliability of gate-oxide in Cascode enhanced GaN power device is studied. The typical degradation of electrical properties was observed. In contrast, the gate current was increased by about two orders of magnitude after 25 MeV and 60 MeV proton irradiation, while the gate current was unchanged significantly after 100 MeV proton irradiation. By using time-dependent dielectric breakdown (TDDB) method confirms that the risk of gate current leakage is increased under proton irradiation. The breakdown time of gate dielectric becomes shorter after proton irradiation, which is not conducive to the long-term and stable application of GaN power devices. In addition, SRIM simulation results show that the interaction cross section between low-energy protons and target nucleus is larger, which will cause more defects in the device, leading to the low-energy proton damage becomes more severe. Proton irradiation produces defects in the gate-oxide layer that shorten the breakdown time of the device gate-oxide layer, ultimately resulting the long-term reliability of the device was reduced.