Experimental Investigation and Analysis of the LDMOS FET Breakdown Under HPM Pulses

In this paper, thermal breakdown effects in a laterally diffused MOS (LDMOS) FET under the impact of high-power microwave (HPM) pulses are investigated by theoretically analyzing, modeling, and measuring. Experimental investigations of the LDMOS FET-based power amplifier (PA) are performed under different pulse durations. The measurement system consists of an adjustable HPM source, one controller, couplers, limiters, attenuators, one four-channel oscilloscope, and a DUT. By increasing the input pulse power level, electrothermal breakdown is observed. The breakdown temperature is calculated by using a 2-D analytic model based on the measured power to failure data. Then, our developed time-domain finite-element numerical algorithm is used to characterize temperature distribution and transient performance of the LDMOS FET. The energy capability, which defines the maximum energy that the device can handle, is 15.5 mJ under the pulse duration of 1 ms with a breakdown temperature of 605 K.