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

doi:10.1016/j.tsf.2005.07.309

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 journal › Article › peer-review

14 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 (P_Ar) of 1.33 × 10 ^{- 1} Pa mixed with a wide range of O₂ partial pressures (P_O) from 1.33 × 10^{- 4} to 4 × 10^{- 1} Pa, equivalent to P_O-to-P_Ar ratios (P_{O / Ar}) from 1 × 10^{- 3} to 3. The effect of varying P_{O / 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 P_{O / Ar} induces a sequence of phase transitions from nanocrystalline β-W(O) (P_{O / Ar} ≤ 0.1), amorphous WO₂ (P _{O / Ar} = 0.6) to amorphous WO₃ (P_{O / Ar} 2). When annealed in argon atmosphere, the amorphous WO₂ and WO ₃ exhibit a very different magnitude of crystallization temperature (T_c) and can be transformed, respectively, into monoclinic WO ₂ (T_c = 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 T_c of 500 °C.

Original language	English
Pages (from-to)	301-306
Number of pages	6
Journal	Thin Solid Films
Volume	493
Issue number	1-2
DOIs	https://doi.org/10.1016/j.tsf.2005.07.309
Publication status	Published - Dec 22 2005
Externally published	Yes

Keywords

Sensors
Sputtering
Tungsten oxide
X-ray diffraction

ASJC Scopus subject areas

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

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10.1016/j.tsf.2005.07.309

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

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.",

keywords = "Sensors, Sputtering, Tungsten oxide, X-ray diffraction",

author = "Ghen, {G. S.} and Liao, {W. L.} and Chen, {S. T.} and Su, {W. C.} and Lin, {C. K.}",

year = "2005",

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doi = "10.1016/j.tsf.2005.07.309",

language = "English",

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AU - Ghen, G. S.

AU - Liao, W. L.

AU - Chen, S. T.

AU - Su, W. C.

AU - Lin, C. K.

PY - 2005/12/22

Y1 - 2005/12/22

N2 - 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.

AB - 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.

KW - Sensors

KW - Sputtering

KW - Tungsten oxide

KW - X-ray diffraction

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ER -

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

Abstract

Keywords

ASJC Scopus subject areas

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