Fabrication of niobium titanium nitride thin films with high superconducting transition temperatures and short penetration lengths

Lei Yu, Rakesh Singh, Hongxue Liu, Stephen Y. Wu, Roger Hu, D. Durand, John Bulman, John M. Rowell, Nathan Newman

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

We report a systematic study of the superconducting and normal state properties of reactively sputtered Nb0.62Ti0.38N thin films deposited on thermally oxidized Si wafers. The superconducting transition temperature (Tc) was found to increase from 12 K for films prepared on unheated substrates to over 16 K for films prepared on substrates maintained at 450°C. A Nb buffer layer was found to improve Tc by ∼0.5 K for growths at lower substrate temperatures. The films fabricated at 450°C have an amply smooth surface (1.5 ± 0.25 nm root mean square roughness), a sufficiently high Tc, and sufficiently small penetration depth (200 ± 20 nm at 10 K) to be useful as ground planes and electrodes for current-generation 10 K rapid single-flux quantum circuit technology.

Original languageEnglish (US)
Pages (from-to)44-47
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume15
Issue number1
DOIs
StatePublished - Mar 1 2005

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Keywords

  • Coherence length
  • Low-temperature superconductors
  • Niobium nitride (NbN)
  • Niobium titanium nitride (NbTiN)
  • Penetration depth
  • Thin film

ASJC Scopus subject areas

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

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