Gate leakage mechanisms of AlN/GaN High electron mobility transistors

In this paper, the gate leakage current of AlN/GaN high electron mobility transistors (HEMTs) at different temperatures and different gate bias voltages was investigated. The gate leakage mechanisms were described by using the dependence between temperature and gate DC characteristics. At room temperature, the maximum saturation current was 868.2 mA/mm, the off-state current was 1x10(-1) mA/mm, and the maximum transconductance was 320 mS/mm at V-d=6 V. The gate leakage mechanisms of AlN/GaN HEMTs were decomposed into two disparate components, including thermionic emission (TE) and Pool-Frenkel (PF) emission. The fitting results show that at the temperatures between 300K and 400K, as the temperature increasing, the gate leakage mechanism was in accordance with the Poole-Frenkel (PF) emission model at reverse gate voltage bias. At forward gate voltages, the gate leakage current was following thermionic emission (TE) model.