Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity - Poster Session

TT 30.67: Poster

Monday, March 31, 2014, 15:00–19:00, P2

Microfabrication of Metallic Magnetic Calorimeters — C. Enss, A. Ferring, A. Fleischmann, L. Gamer, L. Gastaldo, J. Geist, •D. Hengstler, S. Kempf, M. Krantz, A. Pabinger, C. Pies, C. Schötz, V. Schultheiß, and T. Wolf — KIP Heidelberg University.

Metallic Magnetic Calorimeters (MMCs) are low temperature particle detectors that nowadays can reliably be produced with multilayer microfabrication techniques. Moreover, the consequent use of these techniques allows for the fabrication of thousands of virtually identical detectors as it is required for large detector arrays. Using various examples of current MMC detectors which are actively used for spectroscopic measurements, we present our state-of-the-art microfabrication processes. This includes the fabrication of micron wide Nb lines with critical current densities close to the bulk value, persistent current switches allowing for a preparation of a persistent current in these Nb lines, temperature sensors made of co-sputtered Au:Er with concentrations between 200 ppm and 900 ppm, as well as overhanging particle absorbers made of electroplated gold with thicknesses between 3 µm and 200 µm. We also discuss a process for thermal anchoring the detectors through a Si wafer by connecting both sides of the wafer with the help of a DRIE-ICP etch and a Au electroplating process. Finally, we discuss the fabrication of thin, large-area (A > 1 cm²) free-standing absorbers which are connected to the solid substrate only via some stems with a very small diameter.