Theoretical and experimental investigation of gigahertz-band, temperature-compensated electromechanical coupling configurations based on AlN films

Highly c-axis oriented piezoelectric AlN films were sputtered on (0001) Al2O3 substrates and four gigahertz-range surface acoustic wave (SAW) electroacoustic coupling configurations were realized by conventional photolithographic process. The thermal sensitivity of each device was experimentally estimated and found in good accordance with the theoretical predictions. Eight gigahertz-range, thermally compensated SAW devices were obtained for specific AlN thickness, SAW propagation direction, and electrical boundary conditions. A theoretical analysis of the acoustic and electrical behavior of the four coupling structures is proposed to match the achievable performances of the SAW devices with the design requirements.