Thermal stability of SiC JFETs in conduction mode

Although they can operate at elevated junction temperature, silicon carbide power devices can in some cases fail, even at low ambient temperature. This destruction mechanism, called the thermal run-away, is described in the paper. Then, the sensitivity of normally-on SiC JFETs (SiCED) to this mechanism is evaluated using a model based on experimental measurements performed over a wide temperature range (from -50°C to 300°C). It is shown that above a certain current level, run-away can occur. An experimental test bench is used to validate the modelling and explore the safe-operating area of these devices. The measurements confirm the sensitivity of the device to thermal run-away. Mitigation techniques are discussed.