Analysis of the role of the parasitic BJT of Super-Junction power MOSFET under TLP stress

The Super-Junction power Metal-Oxide-Semiconductor Field-Effect-Transistor (SJ-MOSFET) is one of the main switches in solar, lighting, consumer, server, and telecom applications. Among other market requirements a long lifetime is crucial, thus device robustness and reliability are decisive in quality assessment. Several failures are attributed to the action of the parasitic Bipolar Junction Transistor (BJT) inherent to the physical structure of the SJ-MOSFET. Our purpose is to gain insight into the role of the parasitic BJT under fast voltage pulse condition and to determine if the Transmission Line Pulse (TLP) can be used as a new method for predicting the Single Event Burnout (SEB) sensitivity of SJ-MOSFETs. SEB is caused by extreme localized triggering of the parasitic BJT while the whole device is in the off-state. However, TLP is uniform across a device and drives it into the avalanche multiplication regime. We demonstrate by direct comparison to equivalent SJ-Diodes that the parasitic BJT stabilizes the SJ-MOSFET when subjected to high voltage pulses generated by a TLP system. We conclude that the fast voltage method is not suited for emulating cosmic ray induced failure, but shows immense potential in analyzing device failure in other regimes.