Degradation in electrothermal characteristics of 4H-SiC junction barrier Schottky diodes under high temperature power cycling stress

Abstract

The electrothermal characteristics and degradation mechanism of 4H-SiC JBS under high temperature power cycling (HTPC) stress were investigated based on thermal structure function, failure analysis and electrothermal simulation. Results show that, the HTPC stress at different temperature conditions (maximum junction temperature Tjmax = 150 °C and Tjmax = 200 °C) have different effects on the reverse breakdown voltage (Vbr), reverse leakage current and the on-resistance (Ron-sp). It was that the increased reverse leakage currents with HTPC stress are due to the Schottky barrier lowering at the beginning. However, as the heat concentration effect increased at the metal/4H-SiC interface, the contribution of tunneling to leakage current is the major components. So the heat flux path and thermal distribution are very crucial to the reliability of chip and package. It can be concluded that the degradations of die-attach, die surface and metal/SiC interface are the main reliability limiting factors of SiC JBS diodes under high temperature applications.