In this paper, the influence of gate voltage dependent piezoelectric polarization on the damage effect of GaN HEMT induced by high power electromagnetic pulse was investigated in detail. Firstly, the necessity of considering gate voltage dependent piezoelectric polarization charge is stated theoretically. Secondly, by adding the polarization vector of z-axis PZPE, the modified polarization model is constructed. Then series of gate injection experiments were carried out with the help of TCAD simulation software to analysis the damage effect and the influence of gate voltage dependent piezoelectric polarization on the damage threshold of GaN HEMT caused by high power EMP. The results show that the threshold power and threshold energy of the device are reduced due to the temperature rise of the device becoming steeper at the same injected power and the damage time of the device shorter when considering the gate voltage dependent piezoelectric polarization. This conclusion is very important for device design using GaN materials especially when the device operates under high voltage conditions.
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