Relationship of Nb Surface Morphology and Al Coverage to the Intrinsic Stress of Magnetron-Sputtered Nb Films

K. Tsukada, J. Kawai, G. Uehara, H. Kado

Research output: Contribution to journalLetter

16 Citations (Scopus)


To optimize Nb/Al-AlOx/Nb Josephson junctions, atomic force microscopy is used to study the morphology of dc magnetron-sputtered Nb and Al. When the intrinsic stress of Nb films is varied by adjusting Ar pressure, the roughness of Nb films is correlated with the intrinsic stress. Stress-free Nb films have a smooth surface, without depressions, and a roughness of 14.6 A. The roughness of Al deposited on the Nb films reflects the roughness of the underlying Nb, and an Al thickness of more than 40 A is needed to cover the Nb surface without interruption.

Original languageEnglish
Pages (from-to)2944-2946
Number of pages3
JournalIEEE Transactions on Applied Superconductivity
Issue number1
Publication statusPublished - Mar 1993
Externally publishedYes


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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