10 kV, 39 mΩ·cm² Multi-Channel AlGaN/GaN Schottky Barrier Diodes

Abstract

This work demonstrates multi-channel AlGaN/GaN Schottky barrier diodes (SBDs) with a breakdown voltage (BV) over 10 kV, the highest BV reported in GaN devices to date. The epitaxial structure consists of a p-GaN cap layer and five AlGaN/GaN channels continuously grown on a low-cost 4-inch sapphire substrate. A novel device design is proposed for electric field management, i.e., the p-GaN reduced surface field (RESURF) structure, which balances the net charges in the multi-channel at reverse biases. The SBD with a 98- μm anode-to-cathode length ( L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> ) shows a BV of 9.15 kV and a specific on-resistance ( R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> \scriptscriptstyle ON</sub> ) of 29.5 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , rendering a Baliga's figure of merit (FOM) of 2.84 GW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The SBD with a 123- μm L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> shows a BV over 10 kV and a R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> \scriptscriptstyle ON</sub> of 39 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which is 2.5-fold lower than the R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> \scriptscriptstyle ON</sub> of the state-of-the-art 10-kV SiC junction barrier Schottky diodes. The Baliga's FOMs of our 4.6-10 kV GaN SBDs well exceed the SiC unipolar limit. These results show the great promise of GaN for medium- and high-voltage power electronics.

Topics & Concepts