Evaluating substrate bias on the phase-forming behavior of tungsten thin films deposited by diode and ionized magnetron sputtering

Chen, G.S.; Yang, LM; Tian, Hongwei; Hsu, Ching-Tien

doi:10.1016/j.tsf.2005.02.032

Cited by 28 publications

(19 citation statements)

References 28 publications

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“…On the other hand, the XRD spectrum of the barrier layer shows no peaks revealing its amorphous structure. The formation of βphase depends on the partial pressure of oxygen (or base pressure) in the chamber, the film thickness, substrate bias and deposition rate/deposition power [22][23][24].…”

Section: Structurementioning

confidence: 99%

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CrAlSiN barrier layer to improve the thermal stability of W/CrAlSiNx/CrAlSiOyNx/SiAlOx solar thermal absorber

AL-Rjoub

Rebouta

Vieira

et al. 2019

Solar Energy Materials and Solar Cells

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A B S T R A C TThe influence of adding CrAlSiN barrier layer between the back-reflector tungsten (W) and stainless-steel substrate on thermal stability has been investigated. In previous work, after the annealing in vacuum at 600°C, tungsten diffusion from the back-reflection layer towards the stainless-steel substrate was found. In this study, a barrier layer was added and its influence upon the W diffusion was studied. Several designs of multilayer solar selective absorber for high temperature applications were used to test the thermal and chemical stability and oxidation resistance after vacuum annealing. These samples were characterized by Scanning Electron Microscopy (SEM), Rutherford Backscattering Spectrometry (RBS), X-ray diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and UV-VIS-NIR spectroscopy. All absorber tandems show good thermal stability after vacuum annealing at 600°C and the changes in optical constants solar absorptance (α) and thermal emittance (ε) are negligible. In some cases, small changes in the reflectance curves after the first step of annealing were seen. Some changes were found in the oxide layer, due to the incomplete oxidized Si atoms, as confirmed by FTIR analyses. This cannot justify the increase of NIR reflectance observed in the optical stacks after annealing, which can be due to the phase changes of the back-reflector tungsten layer. All layers of stacks are amorphous, except the tungsten layer, which is polycrystalline and shows a columnar growth. The addition of a CrAlSiN P = 0.11 Pa barrier layer between tungsten and stainless-steel substrate proved to be a good solution to control the diffusion of W atoms towards the substrate, whereas using higher nitrogen partial pressure in the high and the low absorption layers reduce the diffusion of Cr from those layers to surface.

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Section: Structurementioning

confidence: 99%

“…The decrease in the emissivity obtained with the vacuum annealing also supports this conclusion. The β-W phase has higher electrical resistivity than α-W phase [24,28], and the mentioned phase transformation contributes to the resistivity decrease of the W layer and consequent emissivity decrease.…”

Section: Thermal Stabilitymentioning

confidence: 99%

CrAlSiN barrier layer to improve the thermal stability of W/CrAlSiNx/CrAlSiOyNx/SiAlOx solar thermal absorber

AL-Rjoub

Rebouta

Vieira

et al. 2019

Solar Energy Materials and Solar Cells

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“…Reduced tungsten has a stable α-W phase while spheroidized tungsten consists of α-W phase and β-W phase. Meta-stable β-W phase results from the condensed nano-particles which covers the surface of spherical micro-particle [8]. In addition to morphological change, purification of feedstock is another advantage of thermal plasma spheroidization process.…”

Section: Resultsmentioning

confidence: 99%

High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

Han

Choi

et al. 2015

Archives of Metallurgy and Materials

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Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungsten carbide-cobalt hard metal scrap was mechanically broken into particles and then tungsten trioxide particle was recovered by hydrometallurgical method. Recovered tungsten trioxide was reduced to tungsten particle in a hydrogen environment. After that, tungsten particle was melted and solidified to make a spherical one by RF (Ratio Frequency) thermal plasma process. Well spherical tungsten micro-particle was successfully obtained from spent scrap. In addition to the morphological change, thermal plasma process showed an advantage for the purification of feedstock particle.

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“…In this work, we investigate the CTE and the residual stresses of tungsten (W) coatings deposited by Pulsed Laser Deposition (PLD). W coatings are of particular interest in a wide range of technological applications, such as in microelectronic and optoelectronic devices, as absorption layers in X-ray lithography [22,23,24], and in nuclear fusion energy [25,26,27]. Thanks to the high versatility of PLD in tuning many process parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

Coefficient of thermal expansion of nanostructured tungsten based coatings assessed by substrate curvature method

et al. 2018

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The in plane coefficient of thermal expansion (CTE) and the residual stress of nanostructured W based coatings are extensively investigated. The CTE and the residual stresses are derived by means of an optimized ad-hoc developed experimental setup based on the detection of the substrate curvature by a laser system. The nanostructured coatings are deposited by Pulsed Laser Deposition. Thanks to its versatility, nanocrystalline W metallic coatings, ultra-nano-crystalline pure W and W-Tantalum coatings and amorphous-like W coatings are obtained. The correlation between the nanostructure, the residual stress and the CTE of the coatings are thus elucidated. We find that all the samples show a compressive state of stress that decreases as the structure goes from columnar nanocrystalline to amorphous-like. The CTE of all the coatings is higher than the one of the corresponding bulk W form. In particular, as the grain size shrinks, the CTE increases from 5

show abstract

Evaluating substrate bias on the phase-forming behavior of tungsten thin films deposited by diode and ionized magnetron sputtering

Cited by 28 publications

References 28 publications

CrAlSiN barrier layer to improve the thermal stability of W/CrAlSiNx/CrAlSiOyNx/SiAlOx solar thermal absorber

CrAlSiN barrier layer to improve the thermal stability of W/CrAlSiNx/CrAlSiOyNx/SiAlOx solar thermal absorber

High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

Coefficient of thermal expansion of nanostructured tungsten based coatings assessed by substrate curvature method

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