Fig. 1. (Color online) Cross-section of the AlGaN/AlN/GaN/AlGaN HEMT structure simulated in this work.

Fig. 2. (Color online) Simulated (a) DC characteristics for different gate-source voltages and (b) transfer characteristics in the presence of acceptor and donor traps in the GaN channel compared to the case with no traps. Trap energy level is 0.3 eV below E_c for the acceptor and 0.3 eV above E_v for the donor.

Fig. 3. (Color online) Influence of acceptor traps located below the conductance band on the (a) output characteristics, (b) transfer characteristics, and (c) transconductance of the AlGaN/AlN/GaN/AlGaN HEMT device at V_ds = 5 V. Acceptor traps in the GaN channel have a density of 5 × 10¹⁷ cm⁻³.

Fig. 4. (Color online) Influence of acceptor trap concentration on the (a) output and (b) transfer characteristics and (c) the transconductance of the device. Acceptor traps in the channel are located at E_ta = 0.3 eV. The drain voltage is V_ds = 5 V.

Fig. 5. (Color online) Passivated and unpassivated structures under the same bias conditions. (a) The output and (b) transfer characteristics and (c) the transconductance of the device. Acceptor traps in the channel have a density of N_ta = 5 × 10¹⁷ cm⁻³ and are located at E_ta = 0.3 eV below the conduction band.

Fig. 6. (Color online) Influence of the temperature variations on (a) DC characteristics, (b) transfer characteristics, and (c) the transconductance of the device in the presence of acceptor traps (N_ta = 5 × 10¹⁷ cm⁻³, E_ta = 0.3 eV).

Fig. 7. Drain current recovery curve after bias stressing with a pulse width of 1 ms on the gate (V_gs = 0, −5 V and V_ds = 25 V) in the presence of acceptor-like traps (N_ta = 5 × 10¹⁷ cm⁻³, E_ta = 0.3 eV).

Fig. 8. Drain current recovery curve after bias stressing on the gate (V_gs = 0, −5 V and V_ds = 10 V) in the presence of acceptor-like traps (N_ta = 5 × 10¹⁷ cm⁻³, E_ta = 0.3 eV).

Table 1. Summary of the material parameters used in the simulations.