Passivation of Cu via refractory metal nitridation in an ammonia ambient

Daniel Adams, Terry Alford, N. D. Theodore, S. W. Russell, R. L. Spreitzera, J. W. Mayer

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45 Scopus citations

Abstract

Cu-(27at.% Ti) and Cu-(26at.% Cr) alloys codeposited on silicon dioxide substrates were isochronally annealed for 30 min at 400-700 °C in a flowing NH3 ambient. In the Cu-Ti alloy, Ti segregates to the free surface to form a TiNx(O) layer and also to the alloy-SiO2 interface to form a Ti5 Si3 TiOw bilayer structure. Therefore the resulting structure is an almost completely dealloyed Cu layer located between a surface oxygen-rich Ti nitride and Ti-silicide/Ti-oxide bilayer interfacial structure. In the Cu-Cr alloy system, Cr seems to migrate only to the free surface to form a CrNx passivation layer. A 45 nm Al film was deposited after nitridation, whereupon a second anneal was performed to evaluate these nitride layers as diffusion barriers. The Cr-nitride diffusion barrier is stable up to 600 °C compared with Ti nitride that fails at 500 °C. The Cu-Cr nitrided samples also showed an overall lower sheet resistance.

Original languageEnglish (US)
Pages (from-to)199-208
Number of pages10
JournalThin Solid Films
Volume262
Issue number1-2
DOIs
StatePublished - Jun 15 1995

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Keywords

  • Ammonia
  • Diffusion
  • Titanium nitride
  • Titanium oxide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

Cite this

Adams, D., Alford, T., Theodore, N. D., Russell, S. W., Spreitzera, R. L., & Mayer, J. W. (1995). Passivation of Cu via refractory metal nitridation in an ammonia ambient. Thin Solid Films, 262(1-2), 199-208. https://doi.org/10.1016/0040-6090(94)05805-9