Over 450 V breakdown voltage in diamond vertical Schottky barrier diodes with anodic self-aligned mesa termination

In this work, diamond vertical Schottky barrier diodes (SBDs) with anodic self-aligned mesa termination were proposed and investigated. This kind of termination structure can effectively alleviate the electric field crowding at the Schottky electrode edge to avoid premature breakdown of the SBD, thus achieving high reverse blocking voltage. The targeted device showed prominent diode properties with a specific on-resistance of 4.0 mΩ/cm⁻² and an on/off ratio of 10⁹. The maximum blocking voltage increased from 206 to 460 V after utilizing mesa termination. The reverse leakage current was maintained below 10⁻² A/cm² until breakdown occurs. The mesa termination structure was analyzed theoretically by Silvaco TCAD, whose profiles showed that electrical concentration appears at the diamond mesa sidewall, and the peak electric field strength becomes lower with increasing mesa depth. These results indicate a feasible way to modify the electric field distribution and enhance the breakdown voltage of the diamond SBD.