Characterization of microstructure, interfacial reaction and diffusion of immiscible Cu(Ta) alloy thin film on SiO2 at elevated temperature

C. J. Liu, Jen-Sue Chen, Y. K. Lin

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16 Citations (Scopus)

Abstract

Thin films of pure Cu along with Cu alloys with 0.1 or 2.3 atom % Ta were deposited on SiO2-covered Si substrates and subsequently annealed at 500-800°C in a vacuum. X-ray diffraction indicates that as compared to the pure Cu sample, the face-centered cubic Cu(111) interplanar spacing increased in the as-deposited Cu (2.3 atom % Ta) sample because the Ta additives dissolved in the Cu films, indicating a nonequilibrium, super-saturated Cu(Ta) solid solution formed by cosputtering deposition. After annealing, the resistivity of all samples was reduced and the lattice spacing of Cu(Ta) films was restored to that of pure Cu film. Scanning electron microscopy shows that the surface of the Cu (2.3 atom % Ta) system remained smooth, and transmission electron microscopy reveals that the degree of Cu grain growth was very small after annealing. Rutherford backscattering spectrometry indicates that the Cu(Ta) samples exhibited less diffusion of Cu into SiO2 after annealing at 700°C, which can be attributed to the formation of a Ta2O5 (or TaOx) layer at the Cu(Ta)/SiO2 interface, as revealed by X-ray photoelectron spectroscopy analysis. The connections between the Ta alloying contents and the microstructural as well as interfacial characteristics of Cu on SiO2 are discussed.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume151
Issue number1
DOIs
Publication statusPublished - 2004 Feb 16

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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