Analysis of dispersive electroacoustic coupling configurations for application to gigahertz-band, temperature-compensated AlN-based acoustic devices

AlN films, 1.4–6.2 ?m thick, were sputtered on z-cut Al2O3 substrates and four electroacoustic coupling configurations were realized and characterized for x and y surface acoustic wave (SAW) propagation directions. The temperature-coefficient of delay dispersion curves of the four configurations was experimentally evaluated and eight temperature-compensated points were estimated. The velocity anisotropy of the multilayers was investigated for different AlN film thicknesses, electric excitation conditions, and temperature values. The design trade-offs required for temperature-compensated, 50 ? matched, gigahertz-range, enhanced-coupling, low loss SAW devices are provided for the four dispersive coupling configurations.