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arXiv · 1104.3518

Atomic layer deposition and superconducting properties of NbSi films

Thomas Proslier·Jeffrey A. Klug·Jeffrey W. Elam·Helmut Claus·Nicholas G. Becker·Michael Pellin
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Abstract

Atomic layer deposition was used to synthesize niobium silicide (NbSi) films with a 1:1 stoichiometry, using NbF5 and Si2H6 as precursors. The growth mechanism at 200oC was examined by in-situ quartz crystal microbalance (QCM) and quadrupole mass spectrometer (QMS). This study revealed a self-limiting reaction with a growth rate of 4.5 {\AA}/cycle. NbSi was found to grow only on oxide-free films prepared using halogenated precursors. The electronic properties, growth rate, chemical composition, and structure of the films were studied over the deposition temperature range 150-400oC. For all temperatures, the films are found to be stoichiometric NbSi (1:1) with no detectable fluorine impurities, amorphous with a density of 6.65g/cm3, and metallic with a resistivity {\rho}=150 {\mu}{\Omega}.cm at 300K for films thicker than 35 nm. The growth rate was nearly constant for deposition temperatures between 150-275oC, but increases above 300oC suggesting the onset of non-self limiting growth. The electronic properties of the films were measured down to 1.2K and revealed a superconducting transition at Tc=3.1K. To our knowledge, a superconducting niobium silicide film with a 1:1 stoichiometry has never been grown before by any technique.

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Thomas Proslier, Jeffrey A. Klug, Jeffrey W. Elam, Helmut Claus, Nicholas G. Becker, Michael Pellin. 2011-04-18. Atomic layer deposition and superconducting properties of NbSi films. https://arxiv.org/abs/1104.3518

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