Analysis of the UIS behavior of power devices by means of SPICE-based electrothermal simulations

This paper presents an accurate, yet computationally effective, 3-D simulation strategy devised for the UIS analysis of multicellular power transistors, which accounts for electrothermal effects and is based on a circuit representation of the whole device under test. The approach is exploited to examine the correlation between the shape of the avalanche curve of IGBTs and the physical mechanisms occurring during UIS discharging. In particular, an in-depth investigation is performed on a current hopping phenomenon that – although not usually destructive – entails a reduction in both ruggedness and reliability of the device.