Fabrication of new Interdigital Transducers for Surface Acoustic Wave Device

El Fissi, Lamia [UCL] Jaouad, A. [Department of Electrical and Computer, Engineering Faculty of Engineering Sherbrooke, Canada] Vandormael, Denis [SIRRIS-Liege Science Park, Seraing/Belgium] Francis, Laurent [UCL]

We investigate high-performance interdigital transducers (IDTs) for the generation of surface acoustic waves (SAWs) on AT-cut quartz, where the metal fingers are embedded in the substrate. Three micromachining techniques are used to manufacture SAW structures, namely an inductively coupled plasma, a laser etching and a reactive ion etching. An evaporated layer of Al and a Ni thick electroplating are used to grow the metals in the micromachining structures. A chemical mechanical polishing (CMP) technique is used to remove the exceeding metal and keep a flat surface. The electrical characterizations indicate that the fabricated devices are suited for sensing proposes with a low insertion loss and a linear phase. Results are reported emphasizing the efficiency of the Ni damascene process to manufacture SAW sensors with the embedded structures.