Berlin 2024 – scientific programme

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DS: Fachverband Dünne Schichten

DS 11: Poster I (joint session DS/MM/O)

DS 11.10: Poster

Wednesday, March 20, 2024, 17:00–19:00, Poster B

RF-sputtering of Nb and NbN thin films for quantum transport studies — •Peer Heydolph, Vincent Strenzke, Isa Moch, Annika Weber, Lars Tiemann, and Robert Blick — Center for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany

Niobium plays a vital role in research and applications, contributing to advancements in superconductivity, quantum computing, and high-performance electronics. Here, we investigate the impact and interdependence of growth parameters on the properties of radio-frequency (RF)-sputtered niobium (Nb) and niobium nitride (NbN) thin films with a high critical temperature for applications in nanostructures and quantum transport studies at 4.2 Kelvin. We demonstrate that high quality superconducting films can be consistently produced even in a basic sputtering setup. We systematically varied the growth parameters such as the power of the RF-plasma and the flow of argon and nitrogen and survey their effects and interdependence on the properties of the thin films. The quality of the resulting films was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) and profilometer measurements to gauge the film thickness. For electrical characterization at various temperatures and magnetic fields we employed a PPMS cryostat. We found that lower flow rates or RF powers do not necessarily lead to a higher critical temperature for NbN, which is in agreement with previous publications. Furthermore, it is crucial to finely tune all parameters and take into account their interdependencies.

Keywords: Thin films; Deposition; Sputter; Niobium; Niobium nitride