Fracture resistance of Ti-Ag thin films deposited on polymeric substrates for biosignal acquisition applications

The ability of magnetron sputtered Ti-Ag thin films deposited on polymeric substrate to be used as sensors for biosignal acquisition is investigated. Influence of the Ag content on the microstructure of TiAgx thin films prepared by magnetron sputtering is characterized by X-ray diffraction and electron microscopies. Three characteristic composition ranges are identified: Ti-rich, Ti-Ag and Ag-rich thin films. Their mechanical and electrical properties are then evaluated. Thin film fracture resistance on polymer substrate (polyethylene terephthalate) is studied by scanning electron microscopy micrographs performed during an in situ uniaxial stretching test. The key role of thin film composition and microstructure is highlighted, pointing out the positive effect of silver.