Young's Modulus and Poisson's Ratio Characterization of Tungsten Thin Films Via Laser Ultrasound

Grünwald, E.; Nuster, Robert; Treml, R.; Kiener, Daniel; Paltauf, Guenther; Brunner, Roland

doi:10.1016/j.matpr.2015.09.015

Cited by 18 publications

(1 citation statement)

References 15 publications

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“…The magnitude of the strain was measured as +0.457(3)%, and after correction for the LaB 6 offset of 0.019% was determined to be +0.476(3)% tensile in-plane strain. Taking the Young's modulus for W as 405 GPa (as per Grünwald et al , 2015), the resulting estimated in-plane stress was calculated to be 1.93 GPa. This value, while very large, is comparable with Lita et al (2005) who found tensile in-plane stresses in their W films on the order of 1.3 GPa.…”

Section: Resultsmentioning

confidence: 99%

Texture and strain analysis of tungsten films via Tilt-A-Whirl methodology

et al. 2022

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Tungsten (W) films have many applications in the semiconducting industry for sensor technology. Deposition conditions can significantly impact the resulting W films in terms of the phases present (α-BCC or β-A12), microstructural grain orientation (texture), and residual strain. Tilt-A-Whirl methodology has been employed for the evaluation of a W film showing both texture and residual strain. Sin2(ψ) analysis of the film was performed to quantify the strongly tensile in-plane strain (+0.476%) with an estimated in-plane tensile stress of ~1.9 GPa. The 3D dataset was also evaluated qualitatively via 3D visualization. Visualization of 3D texture/strain data poses challenges due to peak broadening resulting from defocusing of the beam at high ψ tilt angles. To address this issue, principal component analysis (PCA) was employed to diagnose, model, and remove the broadening component from the diffraction data. Evaluation of the raw data and subsequent corrected data (after removal of defocusing effects) has been performed through projection of the data into a virtual 3D environment (via CAD2VR software) to qualitatively detect the impact of residual strain on the observed pole figure.

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Section: Resultsmentioning

confidence: 99%

Texture and strain analysis of tungsten films via Tilt-A-Whirl methodology

et al. 2022

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Amorphous Silicon Self‐Rolling Micro Electromechanical Systems: From Residual Stress Control to Complex 3D Structures

2019

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In surface micromachining, the control of the residual stress of the films is crucial, as excessive stress can cause buckling, cracking, and peeling of the materials and fracture of the devices. However, the gradients of stress across the thickness of individual films or the stress mismatch in composite structural layers can be exploited to obtain highly complex 3D structures via self‐assembly, self‐bending, self‐positioning, or self‐rolling processes. Herein, the thin‐film residual stresses of amorphous silicon, TiW, AlSiCu, Cr, Au, and SiO2 are assessed using polymer substrates and tuned. Then, a stress‐mismatched bi‐layer of amorphous silicon (tensile) and TiW (compressive) is used in the fabrication of complex 3D self‐rolling micro electromechanical systems (MEMS) structures. The freestanding regions of the fabricated MEMS have a characteristic radius of curvature of ≈100 μm. Current‐induced thermal actuation of a suspended plate is demonstrated. The microfabrication process and materials used are compatible with standard cleanroom processing and with a variety of substrates. In the future, amorphous silicon photodiodes, photoconductors, or other semiconductor devices can be incorporated on complex MEMS fabricated by self‐rolling/self‐bending processes and applied to localized optical and electrical sensing.

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Surface acoustic wave spectroscopy for non‐destructive coating and bulk characterization at temperatures up to 600°C enabled by piezoelectric aluminum nitride coated sensor

Makowski,

Zawischa,

Schneider

et al. 2024

Surface & Interface Analysis

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Surface acoustic wave spectroscopy has been established as non‐destructive and fast method for characterization of mechanical properties of surfaces and bulk materials in both research and industry. The present work shows that by application of a novel and robust aluminum nitride (AlN) coated piezoelectric contact sensor the advantages of the method can be extended from room temperature to at least 600°C. An overview of sensor concepts and applications of the method is discussed first, followed by theoretical and practical considerations for design and coating of a novel temperature stable contact sensor. After fabrication of such a sensor using magnetron sputtering, it was tested in a modified surface acoustic wave spectroscopy setup with an incorporated heating table concerning signal amplitude and frequency range. The AlN coated sensor was found to perform well up to 600°C, with temperature limited by the specification of the heating table. At room temperature, performance was acceptable when compared with a conventional contact sensor using a PVDF piezoelectric foil. Application of the high temperature capabilities of the setup was demonstrated by measuring temperature stability of hydrogen‐free amorphous carbon coatings (a‐C and ta‐C) depending on their sp3 carbon ratio. In another example, high precision temperature dependent measurement of Young's modulus for ultrasonic fatigue test specimen was taken, achieving an accuracy better than 1%. Use of the developed sensor opens up new possibilities in material science for in situ study of temperature depending mechanical properties for coatings and surfaces.

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Young's Modulus and Poisson's Ratio Characterization of Tungsten Thin Films Via Laser Ultrasound

Cited by 18 publications

References 15 publications

Texture and strain analysis of tungsten films via Tilt-A-Whirl methodology

Texture and strain analysis of tungsten films via Tilt-A-Whirl methodology

Amorphous Silicon Self‐Rolling Micro Electromechanical Systems: From Residual Stress Control to Complex 3D Structures

Surface acoustic wave spectroscopy for non‐destructive coating and bulk characterization at temperatures up to 600°C enabled by piezoelectric aluminum nitride coated sensor

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