Semipolar (11 2¯ 2) AlN/AlGaN quasi-vertical Schottky barrier diodes grown on m-sapphire

Abstract

In this work, we demonstrate the semipolar (11 2¯ 2) AlN/AlGaN Schottky barrier diodes (SBDs) on m-plane sapphire by metal organic chemical vapor deposition. Owing to the combination of high quality ultra-wide bandgap aluminum nitride (AlN) as the drift layer and AlGaN as the current spreading layer, the quasi-vertical (11 2¯ 2) AlN/AlGaN SBDs exhibit impressive characteristics with a low room temperature ideal factor of 2.05, a high barrier height of 1.89 eV, a rectification ratio of more than 108, the current density of larger than 1 A/cm2, the low specific on-resistance Ron,sp of about 3 Ω.cm2, and the low leakage current of about 1.22 × 10−5 mA/cm2 at 200 V reverse voltage. Especially, the performance of (11 2¯ 2) AlN/AlGaN quasi-vertical SBDs is substantially better than that of single-layer (11 2¯ 2) AlN or AlGaN lateral SBDs, and even comparable to the state-of-the-art polar c-plane AlN-based SBDs reported so far. This work marks a significant milestone in advancing semipolar AlN-based SBDs and shows a promising potential for yielding high-performance ultra-wide bandgap power devices.