First Experimental Demonstration of Monolithic Bidirectional Switch Using GaN Current Aperture Vertical Electron Transistor (CAVET)

Bidirectional switches (BSW) are extensively employed in power applications, particularly in AC-AC matrix converters and solid-state circuit breakers. They facilitate current flow and voltage blocking in both directions symmetrically. Conventional BSWs without monolithic integration comprise discrete power transistors with anti-parallel freewheeling diodes, which results in additional parasitic effects and a large chip area [1] . Wide bandgap semiconductors including Silicon Carbide (SiC) and Gallium Nitride (GaN) have been investigated for building monolithic-integrated BSWs. Particularly, GaN-based monolithic BSWs using High Electron Mobility Transistors (HEMTs) with dual gates have been developed with a shared active region [2] . Owing to the two-dimensional electron gas (2DEG), GaN HEMTs perform reverse conduction in the absence of a body diode [3] . Vertical power device topologies are preferred over lateral counterparts by reducing on-resistance at a given breakdown rating [4] , and thus bidirectional vertical devices have drawn great interest. Monolithic BSWs based on SiC vertical transistors have been studied [5 , 6] , but to the best of our knowledge, no reports exist on GaN vertical devices. GaN Current Aperture Vertical Electron Transistors (CAVETs) are favorable for MHz high-frequency switching due to high carrier mobility [4] , showing a potential to outperform SiC MOSFETs with lower losses by simulation [7] . We demonstrated a monolithic BSW using GaN CAVETs for the first time, and the reverse conduction of CAVETs was investigated.