Functional extension and upgrade of a reactive ion etching tool

利用所要求的资金，将对物理学院洁净室的反应离子蚀刻系统进行升级，增加感应耦合等离子体激发选项。电感耦合等离子体技术允许独立调节离子和等离子体密度。通过这种方式，可以非常精确地控制蚀刻过程，这对于当前的许多研究项目来说是不可或缺的。升级至关重要的项目之一是范德华异质结构的研究。例如，它将允许制造允许研究双层石墨烯中脆弱的分数量子霍尔效应的样品。此外，实验计划调查与扭曲层的二维材料的电子结构。一个目标是更好地理解在扭曲的石墨烯双层中观察到的超导状态。为了揭示这种货车德瓦耳斯异质结构的内在性质，必须防止与衬底的任何相互作用。这可以通过将功能层封装在绝缘氮化硼中来实现。对于该工艺，具有精确控制蚀刻速率的电感耦合等离子体模式是绝对必要的。此外，电感耦合等离子体模式还允许具有高纵横比、高形状保真度和低边缘粗糙度的纳米结构蚀刻，这对于用于相干X射线成像的X射线光学领域是至关重要的，以便在多个尺度上研究生物系统的结构。在这一点上，应用于等离子体技术是至关重要的衍射光学的进一步发展和实现纳米结构的X射线阳极，它可以在低功率下产生纳米焦点。最终，该小组计划展示新概念“芯片上的X射线光学”，旨在实现新颖的泵浦探测，干涉，断层扫描和X射线量子光学实验。升级后的等离子体工具的另一个用例是研究固体和纳米结构中的超快现象，这将允许开发和应用合适的光谱学，显微镜和衍射技术。为此，需要极其紧凑的电子光学器件。它计划制造下一代电子光学使用光刻工艺结合深反应离子蚀刻在应用蚀刻模式。

With the requested funding, the Reactive Ion Etching System in the cleanroom of the Faculty of Physics will be upgraded with the option of inductively coupled plasma excitation. The inductively coupled plasma technology allows an independent adjustment of the ion and the plasma density. In this way, the etching process can be controlled very precisely, which is indispensable for many current research projects. One of the projects that the upgrade is critical for is the investigation of van-der-Waals heterostructures. For example, it will allow to fabricate samples that allow to investigate the fragile fractional quantum Hall effect in bilayer graphene. Additionally, experiments are planned to investigate the electronic structure of 2D materials with twisted layers. One goal is to gain a better understanding of the superconducting state which has been observed in twisted graphene double layers. In order to reveal the intrinsic properties of such van der-Waals heterostructures, any interaction with the substrate must be prevented. This can be achieved by encapsulating the functional layers in insulating boron nitride. For this process, the inductively coupled plasma mode with a precise control of the etching rate is absolutely essential. Moreover, the inductively coupled plasma mode also allows nanostructure etching with high aspect ratio, high shape fidelity and low edge roughness which is critical for the field of X-ray optics for coherent X-ray imaging in order to investigate the structure of biological systems on multiple scales. At this point, the applied for plasma technology is crucial for the further development of diffractive optics and for the realization of nanostructured X-ray anodes, which can generate a nano-focus at low power. Ultimately, the group plans to demonstrate the new concept "X-ray Optics on a Chip", which is intended to realize novel pump-probe, interferometric, tomographic and X-ray quantum optical experiments. A further use case for the upgraded plasma tool is the investigation ultrafast phenomena in solids and nanostructures where it will be allow the development and application of suitable spectroscopy, microscopy and diffraction techniques. For this purpose, extremely compact electron optics are required. It is planned to fabricate next-generation electron optics using lithographic processes in combination with deep reactive ion etching in the applied for etching mode.