Reactive Magnetron Sputter Deposition of Superconducting Niobium Titanium Nitride Thin Films with Different Target Sizes

Boy Gustaaf Cornelis Bos, David Johannes Thoen, E. A.F. Haalebos, P. M.L. Gimbel, T. M. Klapwijk, J. J.A. Baselmans, Akira Endo

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)
135 Downloads (Pure)

Abstract

The superconducting critical temperature (T-\mathrm{c} > 15 K) of niobium titanium nitride (NbTiN) thin films allows for low-loss circuits up to 1.1 THz, enabling on-chip spectroscopy and multipixel imaging with advanced detectors. The drive for large-scale detector microchips is demanding NbTiN films with uniform properties over an increasingly larger area. This paper provides an experimental comparison between two reactive dc sputter systems with different target sizes: A small target (o100 mm) and a large target (127 mm × 444.5 mm). This paper focuses on maximizing the T-\mathrm{c} of the films and the accompanying I-V characteristics of the sputter plasma, and we find that both systems are capable of depositing films with T-\mathrm{c} > 15 K. The resulting film uniformity is presented in a second manuscript in this volume. We find that these films are deposited within the transition from metallic to compound sputtering, at the point where target nitridation most strongly depends on nitrogen flow. Key in the deposition optimization is to increase the system's pumping speed and gas flows to counteract the hysteretic effects induced by the target size. Using the I-V characteristics as a guide proves to be an effective way to optimize a reactive sputter system, for it can show whether the optimal deposition regime is hysteresis-free and accessible.

Original languageEnglish
Article number7752761
JournalIEEE Transactions on Applied Superconductivity
Volume27
Issue number4
DOIs
Publication statusPublished - 1 Jun 2017

Keywords

  • Optimization methods
  • reactive sputtering
  • submillimeter wave detectors
  • superconducting critical temperature
  • superconducting device fabrication
  • superconducting thin films

Fingerprint Dive into the research topics of 'Reactive Magnetron Sputter Deposition of Superconducting Niobium Titanium Nitride Thin Films with Different Target Sizes'. Together they form a unique fingerprint.

Cite this