High-frequency surface acoustic wave device based on thin-film piezoelectric interdigital transducers

Using high-quality epitaxial c-axis PbZr0.2Ti0.8O3 films grown by off-axis magnetron sputtering onto metallic (001) Nb-doped SrTiO3 substrates, a nonconventional thin-film surface acoustic wave device based on periodic piezoelectric transducers was realized. The piezoelectric transducers consist of a series of ferroelectric domains with alternating polarization states. The artificial modification of the ferroelectric domain structure is performed by using an atomic force microscope tip as a source of electric field, allowing local switching of the polarization. Devices with 1.2 and 0.8 um wavelength,defined by the modulation period of the polarization, and corresponding to central frequencies in the range 1.50-3.50 GHz have been realized and tested.