Crosstalk suppression of CMOS compatible AlN based SAW devices on low resistive Si(100)



Aluminum nitride (AlN) based high frequency surface acoustic wave (SAW) devices are produced by using a new CMOS compatible concept. Textured c-axis oriented AlN films have been deposited on tungsten based embedded interdigital transducers (IDTs) by the reactive pulse DC-sputter technique within the thermal budget of back end of line (BEOL) processes. Two SAW Rayleigh modes with different acoustic velocities were measured and identified by finite element method (FEM) simulation (Kaletta and Wenger, FEM Simulation of Rayleigh waves for CMOS compatible SAW devices based on AlN/SiO2/Si(100) (Elsevier Ultrasonics, available online 18 April 2013, ISSN 0041-624X, 10.1016/j.ultras.2013.04.009) [1]). Electromagnetic crosstalk between in- and output IDTs via low resistive Silicon substrates is one of the most troublesome sources of integrated SAW devices. The impact of several device parameters like the acoustic aperture, the number of fingers and the delay line length on the electromagnetic crosstalk was studied and routes for optimizing SAW filter designs on low resistive Si(100) will be presented. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)