Beta-gallium oxide (β-Ga₂O₃) is an ultrawide bandgap semiconductor that has potential for power electronic applications and devices operating at high temperatures. Particularly important for these applications are its 4.9 eV bandgap, facile electron doping, and the ability to grow β-Ga₂O₃ crystals from the melt. In this work, vertical β-Ga₂O₃ Schottky barrier diodes were fabricated using Pt Schottky and Ti-based Ohmic contacts and Au contact pads on unintentionally doped n-type, ($\overline{2}01$)-oriented single crystal substrates. The diode’s temperature-dependent electrical properties up to 400 °C were investigated, and the Pt/Ga₂O₃ Schottky barrier height was determined to be close to 1.2 eV. The degradation of the contacts over multiple cycles up to 400 °C was observed, resulting in a significant increase in series resistance of the diodes by 1000× at ambient temperature after they were cycled. According to electron microscopy measurements, this degradation is likely due in part to the migration and oxidation of Ti at the top surface of the Au contact pads. This degradation highlights the need for further research and development to ensure stable Ohmic and Schottky contacts to Ga₂O₃ at temperatures above 400 °C.

中文翻译：

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β-Ga2O3肖特基势垒二极管在高温下的性能和可靠性

β-氧化镓 (β-Ga ₂ O ₃ ) 是一种超宽带隙半导体，具有在高温下工作的电力电子应用和设备的潜力。对于这些应用特别重要的是其 4.9 eV 带隙、容易的电子掺杂以及从熔体中生长 β-Ga ₂ O ₃晶体的能力。在这项工作中，垂直 β-Ga ₂ O ₃肖特基势垒二极管是使用 Pt 肖特基和基于 Ti 的欧姆接触以及非故意掺杂的 n 型上的 Au 接触垫制造的，（$\overline{2}01$) 取向的单晶衬底。研究了二极管在高达 400 °C 时的温度相关电特性，并确定 Pt/Ga ₂ O ₃肖特基势垒高度接近 1.2 eV。观察到触点在高达 400°C 的多次循环中退化，导致二极管在循环后在环境温度下的串联电阻显着增加 1000 倍。根据电子显微镜测量，这种退化可能部分是由于金接触垫顶面 Ti 的迁移和氧化。这种退化凸显了进一步研究和开发的需要，以确保在 400 °C 以上的温度下与 Ga ₂ O ₃保持稳定的欧姆和肖特基接触。