Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 17: Cryogenic Detectors and Cryotechnique
TT 17.6: Talk
Wednesday, September 7, 2022, 11:00–11:15, H22
Opimization of MoSi film deposition for superconducting single-photon detectors in the telecom c-band — •Stefanie Grotowski1, Lucio Zugliani2, Rasmus Flaschmann2, Stefan Strohauer1, Christian Schmid2, Fabian Wietschorke2, Sven Ernst1, Simone Spedicato1, Mirco Metz2, Björn Jonas2, Kai Müller2, and Jonathan Finley1 — 1Walter Schottky Institute and Physics Department, Technical University of Munich, Germany — 2Walter Schottky Institute and Department for Electrical and Computer Engineering, Technical University of Munich, Germany
Superconducting single-photon detectors (SSPDs) are a crucial building block for photonic quantum technologies. With regard to the telecommunication infrastructure, SSPDs sensitive in the telecom c-band are required. A promising material in this regard is MoSi, as it unites a small superconducting energy gap enabling high sensitivity while maintaining a high transition temperature. In this work we aim at optimizing the magnetron co-sputtering deposition to achieve high transition temperatures (Tc). We vary the stoichiometry and find maximized Tc values for Mo rich films until an upper limit of around 80% Mo is reached. Above this critical concentation grazing incidence diffration reveals the transition to a polycrystalline phase in the material. Moverover, the working pressure during deposition influences both Tc and structure as well. We find that a low working pressure improves the Tc, but a minimum pressure is required to ensure an amorphous deposition. Finally, with the optimized parameter set we measured a Tc of 8.4 K for 20 nm and 6.2 K for 4.5 nm thin films.