Vertical GaN Schottky Barrier Diode Using Nitrogen Ion Implantation to Form a Donut-Shaped Channel

This paper proposes the use of nitrogen ion implantation to form circular and donut-shaped channels in vertical GaN Schottky barrier diodes (SBDs). Nitrogen ions with a dose of 1 × 10¹⁵ cm⁻² and energy of 100/150 keV were used to form a current blocking layer to separate the channel from the mesa edge, thus reducing the etching damage-induced leakage in the reverse bias. SBDs with circular and donut-shaped channels exhibited reduced leakage current, and hence, increased breakdown voltage. In addition, the SBD with a donut-shaped channel exhibited improved specific on-resistance (R_ON) because it had a wider current spread than did the SBD with a circular channel. Moreover, a floating metal ring (FMR) was added to the SBD with a donut-shaped channel to improve the forward- and reverse-bias characteristics.