Impact of load-pulse duration on power-cycling capability of SiC devices

Inhalt:
In this paper, we discuss the influence of different load-pulse durations ton on the power-cycling (PC) capability of SiC devices. We show that for all tested times between 0.5 s and 60 s, the failure mechanism remains solder degradation, as already known for ton=2 s. An assumed power law dependence of cycle numbers on turn-on time is described by two similar fitting approaches with and without saturation. Dependencies are extracted from the data by the least-square fitting procedure. Both derived parameter sets are similar to known values for silicon chips. Thus, different mechanical properties of the base material do not influence the ton dependency; only the absolute number of cycles is reduced. Additionally, we are able to verify the degradation models proposed by [1 – Herold, C.; Schäfer, M.; Sauerland, F.; Poller, T.; Lutz, J.; Schilling, O.: Power cycling capability of Modules with SiC-Diodes; Proc. CIPS, 2014].