Research On The Damage Effect And Mechanism Of Silicon PNP Darlington Transistor Caused By Microwaves

As an important form of high electromagnetic pulse(HEMP),high power microwave(HPM)has the characteristics of high frequency,short pulses(tens of nanoseconds)and high power,which can cause temporary and permanent damage on the electronic equipment and semiconductor devices through the front door coupling and back door coupling.Therefore,it is very significant for microwave protection to study the interference and damage effects of electronic equipment and semiconductor devices which is induced by HPM.Darlington transistor is widely used in large load driving circuit,power amplifier circuit,switch circuit and automatic control circuit because of its advantages such as large current,high gain,small volume,fast switching speed and easy integration.In this paper,a two-dimensional electron-thermal model of the silicon PNP monolithic Darlington transistor structure is established for the first time,the damage effects and mechansim of the Darlington transistor in the forward-active region are simulated with the injection of HPM.The main studies and conclusive results are as follows:Firstly,the transient behaviors of the monolithic Darlington transistor in the forward-active region are simulated with the injection of HPM from the collector,base and emitter,respectively.By analyzing the variations of the internal distributions of the electric field,the current density and the temperature with time,a further discussion and a comparison of the damage effects and the mechanism of the device under the injection of HPM are performed.The results show that the base injection is easier to burnout the device than collector injection,and there are two damage points which are between the base and the emitter of T1 and T2 transistor,respectively.the device is the least vulnerable when HPM is injected from the emitter,and only one damage location lied in the cylindrical region of base-emitter junction of T2 transistor.The damage location of collector injection is the same as the emitter injection.Secondly,the influence of microwave parameters and structure parameters on device was discussed when HPM is injected from collector.The results indicate that the damage time decreases with increasing amplitude;the increase of the frequency not only reduces the damage time of the device,but also affects the distribution of the damage location;for the repetitive pulse with same pulse width and different pulse repetitive frequency(PRF),temperature accumulation increases as PRF increases,and the peak temperature has almost no change when PRF is lower than 200 KHz;for a certain average power,the value of temperature accumulation decreases with the increases of duty cycle;in addition,three kinds of voltage signals,such as triangle wave,sine wave and square wave,are respectively injected from the collector.Simulation results show that the square is easier to burnout the device than the sine wave,and the triangle wave is the most difficult to damage the device.In addition,the reinforcement method of device is discussed,the results indicate that the lower the substrate concentration is,the less damage to the device;meanwhile,a series of resistor in the emitter can effectively prolong the damage time of the device;besides,the structure of monolithic Darlington transistor can also affect the damage effects.Finally,The dependence of damage energy and damage power of EMP injection and HPM injection from collector on pulse-width are obtained in a nanosecond.The results show that the damage energy threshold increases with the increase of pulse-width,while the damage power threshold decreases with the increase of pulse-width.A conclusion can be made that EMP injection can burnout the device using less energy and power compared with HPM injection.The relation between the damage power and the pulse width of base injection and emitter injection are given respectively,and the result of comparison manifest that the damage power threshold of the base injection is the smallest,and the damage power threshold is maximum when HPM or EMP is injected from the emitter.The work of this paper has some theoretical guiding significance for HPM damage effect and mechanism research of electronic devices and equipment.