We developed a low-temperature ohmic contact formation process for N-polar GaN surfaces. Specific-contact-resistances of 9.4 × 10⁻⁵ and 2.0 × 10⁻⁵ Ω cm² were obtained using Ti/Al metal stacks on heavily-germanium-doped GaN films, which were deposited at 500 °C and 600 °C using a radical-assisted reactive sputtering method, respectively. The electrode sintering temperature was as low as 475 °C. Carrier concentrations for the 500 °C and 600 °C samples were 2.6 × 10²⁰ and 1.8 × 10²⁰ cm⁻³, respectively. These results suggest that this method is highly effective in reducing the contact resistance of GaN devices with low thermal budgets.

中文翻译：

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利用低温反应溅射技术沉积的重Ge掺杂n型GaN薄膜在N极性GaN表面上实现低比接触电阻

我们开发了一种用于 N 极 GaN 表面的低温欧姆接触形成工艺。使用重掺锗 GaN 薄膜上的 Ti/Al 金属叠层获得了9.4 × 10 ^-5和 2.0 × 10 ^-5 Ω cm ²的比接触电阻，该薄膜是使用 500 °C 和 600 °C 沉积的。分别采用自由基辅助反应溅射法。电极烧结温度低至475℃。 500℃和600℃样品的载流子浓度分别为2.6×10 ²⁰和1.8×10 ²⁰ cm ^-3。这些结果表明，该方法在降低低热预算的 GaN 器件的接触电阻方面非常有效。