Dispersion of electrical characteristics and short-circuit robustness of 600V E-mode GaN transistors

This paper presents an experimental study of the robustness of 600 V normally-off GaN High Electron Mobility Transistors (HEMT) submitted to Short-Circuits (SC) operations. The obtained results reveal a severe dispersal in terms of SC robustness: some devices were able to support SC of a very long duration but others failed immediately, for the same electrical and thermal initial constraints. In order to understand this dispersal, static characterizations and collapse-related measurements have been carried out on a large number of devices from the same manufacturer with the same blocking voltage and different current ratings. Then, destructive short-circuits were launched on these transistors. Finally, the time leading to failure (TLF) for a given DC voltage was correlated with the parameters extracted from the characterizations.