Survivability of AlGaN/GaN HEMT

Using harmonic balance simulations, we have examined the survivability limiting mechanisms of a 0.2 mu m T-gate AIGaN/GaN HEMT device under RF overdrive. Simulations are performed using a 4-finger 200 mu m AlGaN/GaN HEMT device model. Two catastrophic failure mechanisms are identified. At low quiescent drain-source voltages (<10V), the forward turn-on of the gate diode may exceed the burnout limit, resulting in a sudden failure. Increasing the quiescent drainsource voltage increases the peak drain-gate voltage and changes the failure mechanism to gate-drain reverse breakdown. The model is consistent with experimental measurements.