Trapping Effects on Leakage and Current Collapse in AlGaN/GaN HEMTs

In this paper, we showcase our investigation regarding the effect of acceptor traps in GaN buffer and AlGaN barrier layers on the leakage current and current collapse in GaN high-electron-mobility transistors. The dependence of current collapse and leakage current on the density and energy level of traps is carefully considered. With an increase in trapping density from 1015 cm−3 to 1018 cm−3, the leakage current was significantly reduced from 80.2% to 1.76% in the buffer layer and 95% to 12.6% in the barrier layer, while the current collapse increased from 6% to 89.8% in the buffer layer and 0.3% to 17.5% in the barrier layer. The effects of current collapse and leakage were more noticeable in the buffer layer than in the barrier layer. Different energy levels (0.75 eV, 1.8 eV, and 2.85 eV) of acceptor traps were likewise studied. It was demonstrated that high-energy traps induced a lower amount of leakage, while the current collapse was greater. Based on these results, a balanced trade-off between the current collapse and the leakage current is proposed.