UHV Sputtering System for the Deposition of Ultrathin Films and Heterostructures

具有定制特性的薄膜和异质结构的可用性对于许多基础物理实验是必不可少的。例如，具有拓扑非平凡能带结构的材料中的特定输运效应、磁性绝缘体中的纯自旋电流或反铁磁异质结构中的磁阻效应只能在适当的样品中进行研究。这里提出的薄膜沉积系统由两个超高真空溅射室组成-一个用于在惰性气氛中沉积金属膜，一个用于在反应或氧化环境中产生氧化物层-通过负载锁连接。这两个独立的溅射室能够使用最佳工艺参数沉积高纯度金属或氧化层，而不会污染或降解室内的其他材料。此外，样品可以通过装载锁从一个溅射室转移到另一个溅射室，而不会破坏真空，因此可以制造具有非常干净的“原位”界面的金属/氧化物异质结构。这种异质结构对于研究电绝缘体中的自旋输运现象是必不可少的。特别是，我们想研究磁序（顺磁，亚铁磁，反铁磁等）的影响。在合适的金属/氧化物异质结构中的纯自旋输运现象。为此，我们打算建立晶体取代铁石榴石层的沉积，其中磁有序温度和其他磁性可以随意调整。这使得系统的自旋输运，自旋动力学和自旋波动实验在不同的磁相和跨相边界。对于磁波动的研究，超薄（几个单层厚）薄膜或具有垂直各向异性的异质结构也是感兴趣的，这只能通过最先进的沉积系统来实现。此外，我们还打算研究大的横向输运效应（反常霍尔或能斯特效应，自旋霍尔效应等）。在某些反铁磁晶体和拓扑学上非平凡的材料中，这又需要制造合适的薄膜或异质结构。最后，从中期来看，超导层和磁性层的整合将允许以空间分辨的方式研究这种界面的局部磁性和电子特性，并可能利用相应的自旋电子功能。总之，这里提出的UHV溅射系统为薄层和异质结构的沉积开辟了质的新的可能性，从而为未来几年的成功研究工作奠定了基础。

The availability of thin films and heterostructures with tailored properties is essential for many fundamental physics experiments. For example, the particular transport effects in materials with topologically non-trivial band structure, pure spin currents in magnetic insulators, or magnetoresistive effects in antiferromagnetic heterostructures can only be studied in appropriate samples. The thin film deposition system proposed here consists of two ultra-high vacuum sputtering chambers – one for the deposition of metallic films in an inert atmosphere, one for the production of oxide layers in a reactive or oxidizing environment – connected by a load lock. The two separate sputtering chambers enable the deposition of high-purity metallic or oxidic layers using optimum process parameters, without contamination or degradation of other materials in the chamber. In addition, the samples can be transferred from one sputtering chamber to the other via the load lock without breaking the vacuum, so that metal/oxide heterostructures with very clean "in-situ" interfaces can be fabricated. Such heterostructures are essential for the investigation of spin transport phenomena in electrical insulators. In particular, we want to study the influence of magnetic order (paramagnetic, ferrimagnetic, antiferromagnetic, etc.) on pure spin transport phenomena in suitable metal/oxide heterostructures. To this end, we intend to establish the deposition of crystalline substituted iron garnet layers, in which the magnetic ordering temperature and other magnetic properties can be tuned at will. This enables systematic spin transport, spin dynamics and spin fluctuation experiments in different magnetic phases and across phase boundaries. For the investigation of magnetic fluctuations, ultra-thin (few monolayers thick) films or heterostructures with perpendicular anisotropy are also of interest, which are only accessible with a state-of-the-art deposition system. In addition, we intend to investigate large transverse transport effects (anomalous Hall or Nernst effect, spin Hall effect, etc.) in certain antiferromagnetic crystals and topologically non-trivial materials, which again requires the fabrication of suitable thin films or heterostructures. Finally, in the medium term, the integration of superconducting and magnetic layers would allow studying the local magnetic and electronic properties of such interfaces in a spatially resolved manner, and to possibly exploit corresponding spin-electronic functionalities. In summary, the UHV sputtering system proposed here opens up qualitatively new possibilities for the deposition of thin layers and heterostructures, thus forming a basis for successful research work in the coming years.