Radiation Effects in AlGaN/GaN HEMTs and Ga2O3 Diodes

Earlier device generations of GaN-based HEMTs were primarily sensitive to displacement damage, and then only at high particle fluence [1]. More recently, devices have become sensitive to TID effects at much lower fluence, as illustrated in Fig. 1 [1], [2]. When GaN-based HEMTs are irradiated with 1.8 MeV protons (Fig. 1(a)), negative threshold-voltage
$V_{\text{th}}$
shifts are observed, consistent with donor-like defect activation. When devices are irradiated with 10-keV X-rays (Fig. 1(b)), for which energies are well below displacement-damage thresholds, negative
$V_{\text{th}}$
shifts are observed [1], [2]. This is strong evidence of TID-induced defect activation. At higher proton fluences, displacement damage leads to the creation of new acceptor-like defects in the devices, e.g., N and Ga vacancies [1], [3]. In subsequent studies on research-grade and industrial AlGaN/GaN HEMTs, TID-irradiation is demonstrated both to activate previously uncharged defects and passivate previously charged defects [1], [4].