Heavy ions sensitivity of power MOSFETs

In order to quantify the heavy ion sensitivity of power MOSFETs, the authors have characterized two technologies (standard and rad-hard) under different accelerators. They have performed two types of experiment: (1) irradiation of the MOSFET in the off-state, static mode, and (2) irradiation of the MOSFET in a switching converter. The tests in static mode on the standard technology have shown that above 50% of the rated voltage of the power MOSFET (100 V and 200 V) these parts can be destroyed by heavy ions. For applications needing higher voltages, the radiation-tolerant parts should be used. It was found that linear energy transfer (LET) is not the right parameter for a complete characterization. For this reason, models using only the LET spectrum are not applicable to event rate prediction of power MOSFETs in space. The energy and range of the particles should be taken into account. The irradiation of the push-pull converter has not led to an improvement of MOSFET behavior under heavy ions. The protection of the transistor depends on the converter capability to provide current to the MOSFET entering breakdown.<
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