Silicon Carbide Power Devices: Progress and Future Outlook

Silicon carbide (SiC) power devices have become commercialized and are being adopted for many applications after 40 years of effort to produce large diameter wafers and high-performance device structures. This article provides a historical perspective of the key breakthroughs that were needed to make progress toward this goal. The junction-barrier-Schottky (JBS) rectifier concept was a critical innovation required to make SiC power Schottky rectifiers viable. The Baliga-Pair or cascode concept was an intermediate step to realize a practical SiC power switch in the 1990 s. An essential unique innovation created in the 1990 s was the shielded planar SiC power MOSFET structure that is now commonly used for commercial products. Shielded trench-gate SiC power MOSFETs were also proposed in the 1990 s, which led to commercial products in the last five years. Although achieving a low specific ON-resistance in SiC power MOSFETs was essential at the inception of the technology, its penetration into power electronics applications is now driven by performance metrics for high-frequency circuits. Device structural enhancements to improve the high-frequency figures of merit are described that have led to major strides in performance. This includes the JBSFET concept where a JBS diode is integrated into the MOSFET structure to suppress current flow through the body diode; the split-gate (SG) and buffered-gate (BG) MOSFET structures that reduce the gate–drain charge; and the OCTFET structure where the gate–drain overlap area is reduced. Future developments in SiC power devices include increasing the blocking voltage rating to expand the applications spectrum. In addition, a SiC monolithic bidirectional switch has been demonstrated to allow implementation of matrix converters, and a SiC monolithic reverse blocking switch has been demonstrated to allow deployment of current source inverters (CSIs).