Nanosecond Risetime Pulse Characterization of SiC pn Junction Diode Breakdown and Switching Properties

Single-shot nanosecond risetime pulse testing of SiC devices is demonstrated to reveal unique and highly crucial device performance information not obtainable by conventional DC and RF electrical testing. This paper describes some strikingly important device behaviors observed during pulse-testing experiments of 4H-SiC pn junction diodes. Specific observations include: 1) a remarkably fast and catastrophic diode failure mechanism in which an SiC diode fails at a fast-risetime pulse amplitude well below the DC-measured breakdown voltage, 2) positive temperature coefficient of breakdown voltage behavior in selected 4H-SiC diodes, and 3) average minority carrier lifetimes extracted from reverse recovery switching transients that are dominated by device perimeter surface recombination effects instead of the carrier lifetime inherent to the bulk SiC material itself. All three of these pulse-revealed behaviors provide important insights into fundamental physical issues that impact the performance and reliability of SiC-based electronics, especially high-power SiC devices.