Synthesis and characterization of polyvinylpyrrolidine assisted tantalum pentoxide films

Vaidyanathan Subramanian, Nicholas Ndiege, E. G. Seebauer, Mark A. Shannon, Richard I. Masel

Research output: Contribution to journalArticlepeer-review


Micron thick tantalum pentoxide (Ta2O5) films have been proposed as thermal insulating layers in microchemical systems, but so far it has been difficult to deposit thick enough films over complex substrates. So far sol-gel films cracked upon heating whenever the film thicknesses were above 350 nm. A 350 nm thick film is too thin for effective insulation. Other techniques are not suitable for coating the complex structures associated with microchemical systems. In this paper we report sol-gel synthesis of 1.6 μm thick tantalum pentoxide (Ta2O5) films. The films are almost crack free, and adhere to silicon surfaces even upon flashing to 900 °C. The key to the synthesis is the addition of Polyvinylpyrrolidine (PVP) to the sol. Films grown in the absence of PVP all show cracks upon calcination to 900 °C while few cracks are seen with PVP. X-ray diffraction and Fourier transform infra red analysis show that orthorhombic Ta2O5 is formed in all cases. X-ray photoelectron spectroscopy shows the O:Ta ratio to be 2.8:1. This shows that sol-gel is a viable process for making the micron thick films of Ta2O5 needed as insulators for microchemical systems.

Original languageEnglish (US)
Pages (from-to)4784-4792
Number of pages9
JournalThin Solid Films
Issue number15
StatePublished - Jun 2 2008


  • Binder
  • Films
  • PVP
  • Polyvinylpyrrolidine
  • Sol-gel
  • TaO
  • Tantalum oxide
  • X-ray diffraction

ASJC Scopus subject areas

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


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