Recent Developments and Challenges of Edge Termination Techniques for Vertical Diamond Schottky Barrier Diodes

Thanks to its excellent material properties, diamond-based power electronic devices have garnered widespread attention. The realization of large-sized (over 2 inches) and high-quality single-crystal diamond wafers has significantly accelerated the industrialization of diamond semiconductor materials and devices. Over years of development, diamond Schottky barrier diodes (SBDs) have evolved into three primary device structures: lateral conduction type, quasi-vertical conduction type, and vertical conduction type. However, the performance of these devices has yet to fully unlock the potential of diamond materials. Efficient edge termination structures need to be designed to synergistically optimize the forward turn-on voltage, on-resistance, and off-state breakdown voltage. This paper reviews the research progress on various existing edge termination structures of diamond SBDs, analyzes the advantages of each structure, and discusses the key challenges faced in the device fabrication processes.