4H-SiC Junction Barrier Schottky Diodes and Power MOSFETs with High Repetitive UIS Ruggedness

A test procedure for repetitive unclamped inductive switching (R-UIS) is presented and the results are reported for state-of-the-art 4H-SiC Schottky barrier diodes (SBDs) and MOSFETs. The energies at failure are 8.3, 8.9, and 10.3 J/cm2 for SBD parts rated to 700, 1200, and 1700 V, respectively. The cumulative thermal effects are intentionally weak for this evaluation, and under these conditions the energies to failure are less than 10% lower for repetitive than single-pulse UIS. $1200\ \mathbf{V}/40\ \mathbf{m}\ \mathbf{\Omega}$ MOSFET parts were stressed with 100 mJ pulses and the integrity of the gate oxide was assessed with a TDDB test. The times to failure for fresh and stressed parts are effectively the same. Tests on parts from several SiC device suppliers showed that high R-UIS ruggedness is a major differentiator of Microsemi's SiC technology.