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TT: Fachverband Tiefe Temperaturen
TT 15: SC: Fabrication and Characterization
TT 15.6: Talk
Monday, March 14, 2011, 17:45–18:00, HSZ 301
Structural characterization of buried superconducting Ga rich films in Si — •Jan Fiedler1,2, Viton Heera1, Richard Skrotzki1, Thomas Herrmannsdörfer1, Matthias Voelskow1, Arndt Mücklich1, Bernd Schmidt1, Wolfgang Skorupa1, Gerhard Gobsch2, Manfred Helm1, and Jochen Wosnitza1 — 1Institute of Ion Beam Physics and Materials Research and Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), P.O. Box 51 01 19, D-01314 Dresden, Germany — 2Experimental Physics, Institute of Physics, Ilmenau University of Technology, Weimarer Str. 32, 98693 Ilmenau, Germany
Recently it has been shown that heavily p-doped group-IV semiconductors such as diamond, silicon and germanium can become superconducting at low temperatures. Here, we present a study of Ga-implanted Si that becomes superconducting due to precipitation after annealing. Ion implantation allows introducing a high Ga dose (4E16cm-2) in Si that leads to peak concentrations far beyond the solid solubility limit. Rapid thermal annealing (RTA) causes redistribution of the Ga and re-crystallization of the amorphous implanted Si layer. After annealing at temperatures up to 850°C the implanted layers are polycrystalline and contain Ga-rich precipitates. Structural investigations by means of RBS/C measurements and TEM demonstrate a high density of precipitates at the interface of a protective SiO2 layer and the silicon substrate. At optimized annealing conditions (600-700°C) such samples become superconducting with critical temperatures up to 7 K [1]. [1] Skrotzki R. et al. , Appl. Phys. Lett. 97 (2010) 192505