Characteristics and Operation of a Monolithic Bidirectional GaN-on-AlN/SiC Power Transistor employing Dual-Gate

We demonstrate a novel 650 V/110 mΩ monolithic bidirectional GaN-on-AlN/SiC switch with two Schottky-type gates, which shows back-gating immunity and thus enables straightforward on-chip integration without performance degradation. GaN-based monolithic bidirectional switches (MBDSs) are increasingly reported as a promising option for converter topologies requiring devices with bidirectional voltage blocking and current conducting functionality owing to their advantages of fast-switching, reduced conduction losses, and chip area. Different from discrete unidirectional transistors, two gates are deposited on one chip and a common substrate is shared by the two subswitches. However, few results are available considering the interaction of the two gates and the impact of substrate potential, especially on dynamic performance. In this article, extensive experimental results including both static and dynamic switching characterization of the proposed MBDS are presented with a focus on the impact of the operating status of the second gate and the substrate potential. The static characteristics are also compared with discrete unidirectional devices using the same transistor technology to give more straightforward insight into the operation features of the MBDS. The dynamic characterization is performed in application-oriented operating conditions. The large potential of the proposed switch for achieving high-frequency, high power density converters is demonstrated by validating its operation based on a laboratory T-type converter prototype at 400 V dc-bus voltage, 5 A ac current, and 2 MHz switching frequency.