Progress in Superconductivity

The Korean Superconductivity Society (한국초전도학회)
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Fabrication of Sub-Micron Size $Al-AlO_x-Al$ Tunnel Junction using Electron-Beam Lithography and Double-Angle Shadow Evaporation Technique

전자빔 패터닝과 double-angle 그림자 증착법을 이용한 sub-micron 크기의 $Al-AlO_x-Al$ 터널접합 제작공정개발

  • Rehmana, M. (Korea Research Institute of Standards and Science) ;
  • Choi, J.W. (Department of Physics, KAIST) ;
  • Ryu, S.J. (Department of Physics, KAIST) ;
  • Park, J.H. (Korea Research Institute of Standards and Science) ;
  • Ryu, S.W. (Department of Physics, Chonnam National University) ;
  • Khim, Z.G. (Department of Physics, Seoul National University) ;
  • Song, W. (Korea Research Institute of Standards and Science) ;
  • Chong, Y. (Korea Research Institute of Standards and Science)
  • Published : 2009.04.30
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Abstract

We report our development of the fabrication process of sub-micron scale $Al-AlO_x-Al$ tunnel junction by using electron-beam lithography and double-angle shadow evaporation technique. We used double-layer resist to construct a suspended bridge structure, and double-angle electron-beam evaporation to form a sub-micron scale overlapped junction. We adopted an e-beam insensitive resist as a bottom sacrificing layer. Tunnel barrier was formed by oxidation of the bottom aluminum layer between the bottom and top electrode deposition, which was done in a separate load-lock chamber. The junction resistance is designed and controlled to be 50 $\Omega$ to match the impedance of the transmission line. The junctions will be used in the broadband shot noise thermometry experiment, which will serve as a link between the electrical unit and the thermodynamic unit.

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References

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