Breakdown Mechanisms in <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> Trench-MOS Schottky-Barrier Diodes
Taylor Moule, Stefano Dalcanale, Akhil S. Kumar, Michael J. Uren, Wenshen Li, Kazuki Nomoto, Debdeep Jena, Huili Grace Xing, Martin Kuball
Abstract
The breakdown mechanisms of >1kV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> trench-MOS Schottky-barrier (SB) diodes (SBDs) are investigated during step-stressed voltage measurements. We demonstrate the use of current leakage noise to characterize leakage mechanisms. Comparing the normalized current noise characteristics of a set of trench-MOS SBDs to a metal-oxide-semiconductor capacitor (MOS-CAP) and a planar SBD test structure, the origin of two leakage mechanisms can be discerned. At low biases, leakage is dominated by barrier tunneling at the SB interface. At higher biases, non-reversible soft-breakdown events are observed, with a sharp increase in leakage current associated with breakdown at the oxide interface. Beyond these non-reversible soft-breakdown events, localized Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> leakage paths dominate the leakage noise signature. Changes in the dominant leakage mechanism, under reverse bias stress, have implications for the voltage ratings and lifetimes of reduced surface electric field (RESURF) devices that incorporate oxide layers for enhanced breakdown fields.