12.5 kV GaN Super-Heterojunction Schottky Barrier Diodes

This article reports GaN super-heterojunction Schottky barrier diodes (SHJ-SBDs) with substantially improved performance. Metal-2DEG sidewall n-ohmic contacts were deployed to achieve low contact resistance of $0.75~\Omega ~ \cdot ~mm$ , avoiding the risk of abnormally high contact resistance caused by inaccurate etch depth control. A pGaN notch formed near the cathode successfully eliminated excessive hole conduction caused by the sidewall n-ohmic contact. Isolation was improved by a high-energy Al implantation step. The resulting SHJ-SBD exhibited a breakdown voltage (BV) of 12.5 kV and a specific resistance of 100.8 $\text{m}\Omega ~ \cdot ~cm^{2}$.