High temperature long term stability of SiC Schottky diodes

Reliability of Silicon Carbide (SiC) power devices is still an open problem, preventing a wider application of such a promising technology. Moreover, specific reliability assessment procedures must be developed for SiC devices, as they are designed to work at temperatures well beyond those of standard Silicon devices. A detailed investigation about the reliability of 600 V, 6 A Silicon Carbide Schottky diodes is accomplished along this paper. It is based on an extensive set of high temperature reverse bias endurance tests, performed on devices featuring different packages. Only small forward voltage drop and reverse current drifts have been recorded after a 1000 h long test, confirming the parametric stability and the reliability level reached by last generation SiC Schottky diodes. Moreover, devices assembled in TO220 package without flame retardant components in the molding compound performed better than devices assembled in other TO220 packages, or assembled in hermetic TO3 package, pointing out the role played by the interface between the green molding compound and the top passivation layer in the long term parametric stability.