Damage effect and mechanism of Darlington tubes caused by intense electromagnetic interference

A two-dimensional electron-thermal model of the PNP type Darlington tube is established, and the transient behaviors of the Darlington tube in the forward-active region are simulated with the injection of high power microwaves (HPMs) and electromagnetic pulses (EMPs) from the collector. A discussion and a comparison of the damage effects and the mechanism of the device under the injection of HPMs and EMPs are performed. The results show that temperature variation has a periodic rule of "decrease-increase" and temperature elevation occurs in the positive half-period, and the cylindrical region of base-emitter junction of the second transistor (near the emitter of the Darlington tube) is susceptible to damage when HPM signals are injected. While temperature keeps rising and the rate of increase presents a tendency of "rapid-slow" until the device burns out under the injection of EMP signals, and the damage location is the same as the damage area of HPM injection. In addition, the damage mechanism during the positive half-period of HPM injection is similar to that of EPM injection. Finally, the dependence relations of damage energy and damage power of EMPs and HPMs on pulse-width are obtained in a nanosecond range. It is demonstrated that energy threshold increase slowly while power threshold decrease with the increasing of pulse-width.