Demonstration of high voltage (600–1300 V), high current (10–140 A), fast recovery 4H-SiC p-i-n/Schottky(MPS) barrier diodes

Abstract

In this work, the design, fabrication, and testing of improved, high power 4H-SiC merged p-i-n/Schottky(MPS) diodes, in the 600–1300 V voltage range, are described. Both DC and transient test results are presented. The diodes were designed with a multi-step junction termination extension (MJTE) to improve the blocking voltage. The MJTE design allows full utilization of the superior breakdown properties of SiC. At 600 V, the highest forward current capability of a packaged MPS diode showed a current of 50 A at 2 V and 140 A at 4 V. At 1300 V, the current was 4 A at 2 V and 10 A at 4 V. In addition, the SiC MPS diode reverse voltage showed excellent suppression of the Schottky leakage current at temperatures up to 250 °C. The transient properties were measured with an inductively loaded half-bridge inverter circuit at high current and high temperatures (high- T). Results showed that the replacement of Si freewheeling diodes by SiC diodes results in far less storage charge in the diodes and substantial reduction in diode turn-off energy loss, especially at high- T. Switching measurements at currents up to 230 A compared a SiC MPS and a state-of-the-art Si diode; the MPS showed a 47% energy loss reduction at room temperature and 84% at 200 °C. The IGBT energy loss reduction, when using an MPS diode, was 15% at room temperature and 45% at 150 °C. The use of MPS diodes should result in improved efficiency when used in power electronics applications.