The outstanding oxidation resistance, thermo-mechanical stability, and chemical inertness of alumina, but also the synthesis of phase pure polymorphs attract particular attention in academia and industry. Especially, the difficulties regarding the synthesis of α- or γ-structured Al₂O₃ by physical vapor deposition techniques are still strong limitations. Within this study, we investigated in detail the influence of 2 at.% tungsten in the Al-target on the process stability and phase formation during reactive DC magnetron sputtering as well as high power impulse magnetron sputtering (HiPIMS) of Al₂O₃-based coatings. The small addition of W to the Al target allows to increase the oxygen partial pressure by more than 200% while maintaining a stable deposition process. Ion mass spectroscopy measurements yield a promising high fraction of ¹⁶O⁺ and ³²O₂⁺, when operating the W-containing target in the metal-to-poisoned transition mode. A significant increase of ¹⁶O⁺ is further provided by the target surface oxide in poisoned mode. Detailed time-of-flight ion mass spectroscopy investigations during one HiPIMS pulse show a clear temporal separation of the individual ions arriving at the substrate plane during the pulse on-time, allowing for controlled ion attraction by synchronizing the bias pulse to the discharge impulse. Equal amounts of ²⁷Al⁺ and ³²O₂⁺ can be attracted using a bias on-time between 400 μs and 900 μs in the “off-time” (after glow) leading to a dense and nano-crystalline coating. Detailed electron microscopy investigations show the presence of metallic phase fractions for higher duty cycles (7.5%). Decreasing the duty cycle to 3.75% leads to amorphous coatings when operating the Al-target at the highest oxygen partial pressure in metallic mode.

氧化铝出色的抗氧化性、热机械稳定性和化学惰性，以及相纯多晶型物的合成在学术界和工业界引起了特别关注。特别是，通过物理气相沉积技术合成α-或γ-结构的Al ₂ O ₃的困难仍然是很大的限制。在这项研究中，我们详细研究了 Al 靶中 2 at.% 钨对反应性直流磁控溅射以及 Al ₂ O _{3 的}高功率脉冲磁控溅射 (HiPIMS) 过程稳定性和相形成的影响基涂料。在铝靶中少量添加 W 可以将氧分压提高 200% 以上，同时保持稳定的沉积过程。当以金属到中毒的过渡模式操作含 W 目标时，离子质谱测量产生了有希望的高分数¹⁶ O ⁺和³² O ₂ ⁺。显着增加¹⁶ O ⁺由中毒模式中的目标表面氧化物进一步提供。在一个 HiPIMS 脉冲期间详细的飞行时间离子质谱研究显示，在脉冲导通期间到达基板平面的单个离子在时间上有明显的分离，允许通过将偏置脉冲与放电脉冲同步来控制离子吸引。等量的²⁷ Al ⁺和³² O ₂ ⁺可以在“关闭时间”（辉光后）中使用 400 μs 和 900 μs 之间的偏置导通时间吸引，从而形成致密的纳米晶体涂层。详细的电子显微镜研究表明，存在较高占空比 (7.5%) 的金属相部分。当以金属模式在最高氧分压下操作铝靶时，将占空比降低到 3.75% 会导致非晶涂层。