Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Postersession Superconductivity: Josephson Junctions, SQUIDs, Heterostructures, Andreev Scattering, Vortex Physics, Cryodetectors, Measuring Devices, Cryotechnique
TT 32.3: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Ramp-type Josephson junctions with YBa2Cu3O7 and Nb electrodes — •Andreas Blank, Markus Turad, Christoph Maurer, Christoph Back, Reinhold Kleiner, and Dieter Koelle — PhysikalischesInstitut & Center for Collective Quantum Phenomena, UniversitätTübingen, Germany
We present our status of the development of an improved ramp-type Josephson junction technology for fabrication of all-high Tc junctions with YBa2Cu3O7 (YBCO) electrodes and PbBa2Cu3O7 (PBCO) barrier, and hybrid YBCO/Au/Nb junctions. The fabrication is done in a UHV cluster tool for the deposition of oxide thin films by pulsed laser deposition (PLD) using in-situ high-pressure RHEED for monitoring the thin film growth. Deposition of Nb and Au thin films is done by dc magnetron sputtering and electron beam evaporation, respectively, in two separate processing chambers. A milling chamber equipped with a high-frequency inductively-coupled plasma source allows surface cleaning and etching with argon and/or oxygen, reactive ion etching with SF6 and removal of resist structures in an oxygen plasma. The substrate holder in the milling chamber allows in-situ adjustment and variation of the milling angle and additional rotation of the substrate about its normal axis, in order to realize an isotropic milling process, which is essential for the fabrication of 2-dimensional arrays of Josephson junctions. Initial results on the properties of fabricated ramp junctions will be shown.