Chemistry and resistance at metal contacts to YBa2Cu3O7high Tcsuperconducting thin films
作者:
M. T. Schmidt,
Q. Y. Ma,
L. S. Weinman,
X. Wu,
E. S. Yang,
Chin‐An Chang,
期刊:
AIP Conference Proceedings
(AIP Available online 1990)
卷期:
Volume 200,
issue 1
页码: 218-226
ISSN:0094-243X
年代: 1990
DOI:10.1063/1.39045
出版商: AIP
数据来源: AIP
摘要:
X‐ray photoelectron spectroscopy (XPS) and electrical characterization have been used to investigate metal contacts to thin films of superconducting YBa2Cu3O7−x(YBCO). The metals studied are Au, Pt, Pd, Sn, and Ti, which cover a wide range of physical properties including reactivity with oxygen and bulk resistivity. XPS was also used to investigate the sputter cleaning and subsequent heating of the YBCO films prior to contact formation. Contacts for electrical study were defined by a shadow mask, while contacts studied by XPS were formed by sequential deposition of several A˚ of metal. XPS of the O 1s, Cu 2p, and the various metal core levels confirm that the more reactive metals cause more disruption at the metal/YBCO interface. These observations of interface chemistry are correlated with contact resistivity measured at room temperature and at 77 K. We find that although Au, Pt and Pd have similar contact resistivity at room temperature, only the Au contacts show a large decrease in contact resistance at 77 K. Ti and Sn have much higher contact resistivities at room temperature than the noble metals. These results are discussed in terms of interface chemistry and material properties.
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