| Abstract |
Schottky-diodes in silicon (Si) are well-known for their problematic blocking behaviour at hightemperatures and high blocking voltages. High leakage currents [1] and self-heating can lead to athermal runaway [2] due to the fatal feedback loop of both. Devices produced of silicon carbide (SiC)are expected to avoid this problem by much lower leakage currents due to the higher Schottky barrierheight [1]. Accordingly, this problem was supposed to be solved for good. However, early SiCSchottky-diodes suffered from non-ideal leakage current densities [3] [4] [5] and were highlyendangered by thermal runaway. In this work the blocking stability of current SiC-Schottky- and SiCpin-diodes is investigated by means of calculation and measurement. Different leakage mechanisms inSchottky- and pin-diodes lead to different voltage and temperature dependencies of the leakagecurrent. The temperature difference _Td, for which a doubling of the leakage current IR occurs, issignificantly higher for SiC-Schottky- and SiC-pin-diodes at nominal voltage than for Si-pin-diodes.Experiments show, that the thermal stability is achieved even under worst cooling conditions or duringhigh temperature operation and thermal runaway during blocking is no longer a limiting factor withinthe specified operating range. However, when going to higher voltages or operating temperatures therisk of thermal runaway has to be reassessed. |
