Abstract
The mixed-mode interfacial adhesion strength between a gold (Au) thin film and an anisotropic passivated silicon (Si) substrate is measured using laser-induced stress wave loading. Test specimens are prepared by bonding a fused silica (FS) prism to the back side of a 〈1 0 0〉 Si substrate with a thin silicon nitride (SixNy) passivation layer deposited on the top surface. A high-amplitude stress wave is developed by pulsed laser ablation of a sacrificial absorbing layer on one of the lateral surfaces of the FS prism. Due to the negative non-linear elastic properties of the FS, the compressive stress wave evolves into a decompression shock with fast fall time. Careful selection of the incident angle between the pulse and the FS/Si interface generates a mode-converted shear wave in refraction, subjecting the SixNy/Au thin film interface to dynamic mixed-mode loading, sufficient to cause interfacial fracture. A detailed analysis of the anisotropic wave propagation combined with interferometric measurements of surface displacements enables calculation of the interfacial stresses developed under mixed-mode loading. The mixed-mode interfacial strength is compared to the interfacial strength measured under purely tensile loading.
Original language | English (US) |
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Pages (from-to) | 51-66 |
Number of pages | 16 |
Journal | Journal of the Mechanics and Physics of Solids |
Volume | 57 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2009 |
Keywords
- Decompression shock
- Dynamic wave propagation
- Laser spallation
- Mixed-mode loading
- Thin film
ASJC Scopus subject areas
- Mechanical Engineering
- Mechanics of Materials
- Condensed Matter Physics