12.5 kV GaN Super-Heterojunction Schottky Barrier Diodes
Sangwoo Han, Jianan Song, Mansura Sadek, Alex Molina, Mona A. Ebrish, Suzanne E. Mohney, Travis J. Anderson, Rongming Chu
Abstract
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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.75~\Omega ~ \cdot ~mm$ </tex-math></inline-formula> , 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega ~ \cdot ~cm^{2}$ </tex-math></inline-formula> .