Effects of deposition and annealing atmospheres on phase transition of tungsten oxide films grown by ultra-high-vacuum reactive sputtering

G. S. Ghen, W. L. Liao, S. T. Chen, W. C. Su, C. K. Lin

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A series of oxygen-contained tungsten films were grown on Si(100) substrates without intentional heating by ultra-high-vacuum reactive magnetron sputtering at a constant argon pressure (PAr) of 1.33 × 10 - 1 Pa mixed with a wide range of O2 partial pressures (PO) from 1.33 × 10- 4 to 4 × 10- 1 Pa, equivalent to PO-to-PAr ratios (PO / Ar) from 1 × 10- 3 to 3. The effect of varying PO / Ar on phase evolution was evaluated by annealing the films in a controlled atmosphere (argon or oxygen) at 500 or 700 °C for 1 h. Grazing incident X-ray diffraction and transmission electron microscopy, together with the data of electrical resistivity and deposition rate, reveal that gradually increasing PO / Ar induces a sequence of phase transitions from nanocrystalline β-W(O) (PO / Ar ≤ 0.1), amorphous WO2 (P O / Ar = 0.6) to amorphous WO3 (PO / Ar 2). When annealed in argon atmosphere, the amorphous WO2 and WO 3 exhibit a very different magnitude of crystallization temperature (Tc) and can be transformed, respectively, into monoclinic WO 2 (Tc = 500 °C) and tetragonal WO3 (T c = 700 °C). However, the oxidizing atmosphere plays a role to accelerate significantly the crystallization of the amorphous WO2 into a completely different phase (monoclinic WO3) at a significantly reduced Tc of 500 °C.

Original languageEnglish
Pages (from-to)301-306
Number of pages6
JournalThin Solid Films
Volume493
Issue number1-2
DOIs
Publication statusPublished - Dec 22 2005
Externally publishedYes

Fingerprint

tungsten oxides
Reactive sputtering
Ultrahigh vacuum
ultrahigh vacuum
Oxide films
Tungsten
oxide films
Argon
sputtering
Phase transitions
argon
Annealing
atmospheres
annealing
Crystallization
crystallization
controlled atmospheres
grazing
oxygen
Oxygen

Keywords

  • Sensors
  • Sputtering
  • Tungsten oxide
  • X-ray diffraction

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Effects of deposition and annealing atmospheres on phase transition of tungsten oxide films grown by ultra-high-vacuum reactive sputtering. / Ghen, G. S.; Liao, W. L.; Chen, S. T.; Su, W. C.; Lin, C. K.

In: Thin Solid Films, Vol. 493, No. 1-2, 22.12.2005, p. 301-306.

Research output: Contribution to journalArticle

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