Progress in Superconductivity

The Korean Superconductivity Society (한국초전도학회)
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A Single-Flux-Quantum Shift Register based on High-$T_c$ Superconducting Step-edge Josephson Junctions

  • Sung G.Y. (Electronics and Telecommunications Research Institute) ;
  • Choi, C.H. (Electronics and Telecommunications Research Institute) ;
  • Suh J.D. (Electronics and Telecommunications Research Institute) ;
  • Han, S. K. (Electronics and Telecommunications Research Institute) ;
  • Kang, K.Y. (Electronics and Telecommunications Research Institute) ;
  • Hwang, J.S. (Dept. of Mat. Eng., Chung Nam Nat'l Univ.) ;
  • Yoon, S.G. (Dept. of Mat. Eng., Chung Nam Nat'l Univ.) ;
  • Jung, K.R. (Dept. of Physics, Univ. of Inchon) ;
  • Lee, Y.H. (Dept. of Physics, Univ. of Inchon) ;
  • Kang, J.H. (Dept. of Physics, Univ. of Inchon) ;
  • Kim, Y.H. (Korea Institute of Science and Technology) ;
  • Hahn, T.S. (Korea Institute of Science and Technology)
  • Published : 1999.08.15
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Abstract

We have fabricated and tested a simple circuit of the rapid single-flux-quantum(RSFQ) four-stage shift register using a single layer high-$T_c$ superconducting (HTS) $YBa_2Cu_3O_{7-x}$ (YBCO) thin film structure with 9 step-edge Josephson junctions. The circuit includes two read superconducting quantum interference devices(SQUID) and four stages. To establish a robust HTS RSFQ device fabrication process, we have focussed on the reproducible process of sharp and straight step-edge formation as well as the ratio of film thickness to step height, t/h. The spread of step-edge junction parameters was measured from each 13 junctions with t/h=1/3, 1/2, and 2/3 at various temperatures. We have demonstrated the simplified operation of the shift register at 65 K.

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