Laser-Induced Surface Acoustic Waves for Thin Film Characterization

Abstract

<jats:p>Knowledge of mechanical properties of thin films is essential for most of their applications. However, their determination can be problematic for very thin films. LAW (Laser-induced acoustic waves) is a combined acousto-optic method capable of measuring films with thickness from few nanometers. It utilizes ultrasound surface waves which are excited via short laser pulses and detected by a PVDF foil. Properties such as Young’s modulus, Poisson’s ratio and density of both the film and the substrate as well as film thickness can be explored.Results from the LAW method are successfully compared with nanoindentation for Young’s modulus evaluation and with optical method for film thickness evaluation and also with literature data. Application of LAW for anisotropy mapping of materials with cubic crystallographic lattice is also demonstrated.</jats:p>

Simulating the filament morphology in electrochemical metallization cells

“…A nanotemplate radius r tem = 2 nm was assumed and the resulting curves for different plausible Young's moduli are plotted. For the Young's modulus of SiO 2 , various values have been reported in literature, from 10 − 40 GPa [55], up to 100 GPa [56]. For thin film HfO 2 values up to 180 GPa have been reported [57].…”

Intrinsic Thermomechanical Properties of Freestanding TEOS-SiO2Thin Films Depending on Thickness

“…Previous researches reported that the tensile properties of the SiO 2 film, utilizing various methods such as nanoindentation, , bulge test, beam bending, , resonance frequency, phase velocity measurement, and Brillouin spectral analysis, have been reported. The CTE of the SiO 2 film was measured via curvature difference resulting from residual stress due to CTE mismatch with the substrate. ,, The presence of the substrate makes it difficult to measure the intrinsic thermomechanical properties of SiO 2 thin films using these methods.…”