Trap states in AlGaN channel high-electron-mobility transistors

Frequency dependent capacitance and conductance measurements were performed to analyze the trap states in the AlGaN channel high-electron-mobility transistors (HEMTs). The trap state density in the AlGaN channel HEMTs decreases from 1.26 × 1013 cm−2eV−1 at the energy of 0.33 eV to 4.35 × 1011 cm−2eV−1 at 0.40 eV. Compared with GaN channel HEMTs, the trap states in the AlGaN channel HEMTs have deeper energy levels. The trap with deeper energy levels in the AlGaN channel HEMTs is another reason for the reduction of the reverse gate leakage current besides the higher Schottky barrier height.