SiN passivation with Si-rich SiN interlayer has been studied in Al_0.25Ga_0.75N/GaN HEMTs. The off-state current (@Vg = -10V) of devices with Si-rich SiN is 3.8×10^-4 mA/mm and that of devices without Si-rich SiN is 0.8×10^-2 mA/mm, respectively. The leakage mechanism of schottky gate AlGaN/GaN HEMTs is dominated by Poole-Frenkel (PF) emission. The extracted trap energy level for HEMTs with Si-rich SiN and without Si-rich SiN are 0.65 eV and 0.26 eV, respectively.
 

AlGaN/GaN HEMTs