Effect of Atomic-Level Roughness on Vertical β-Ga₂O₃ Schottky Barrier Diode and High-Temperature Performance

We demonstrate the atomic scale surface roughness of β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> epitaxial layer by developing a two-step inductively coupled plasma and wet-repair treatment. The superior surface roughness of 0.12 nm and close-to-unity ideal factor (n) of 1.05 were achieved using optimized surface treatment on vertical β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Schottky barrier diodes (SBDs). Compared to untreated samples, the blocking capability was enhanced with increasing breakdown voltage (BV) above 1.6 times. Furthermore, a comprehensive analysis of the electrical properties at high temperature was analyzed to verify that the improved Ni/β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> interface quality can lead to an enhancement of the device performance. When subjected to an off-state stress of -100 V at 175°C, the surface-treated SBDs perform stable forward characteristics with slight current-density degradation (∆J<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf><0.01%). The results pave the way for further improving the surface quality of β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> devices and validate the potential of SBDs in high-temperature power application scenarios.