The junction edge leakage current and the blocking I-V characteristics of commercial glass passivated thyristor devices

Unreliable performance of thyristor devices at junction temperature higher than 125-150degC, cannot be understood if non-negligible leakage current flow at the junction edge is not taken into consideration. Current-voltage blocking (off-state) characteristics have been investigated for medium power thyristor devices available on the market. Typical results are shown at room and high temperature. A split of the two blocking characteristics is attributed to the edge junction leakage current component. Leakage current voltage dependence like V^ln/ where n varies in the range 1-5 is possible. At high temperature, no saturation tendency of the blocking leakage current is observed. Such results are not understandable by considering only the bulk component of the junction current