SURFACE-ACOUSTIC-WAVE PROPERTIES IN ZNO ALN/SI STRUCTURE/

The propagation characteristics of surface acoustic waves (SAW's) in Z nO/AlN/Si three-layered structure are theoretically studied with speci al attention to the effect of a piezoelectric AlN buffer layer. The di spersion curve of the SAW velocity, the electromechanical coupling coe fficient and the displacements are calculated as functions of the thic knesses of the ZnO and AIN films for the zeroth Rayleigh and Sezawa mo des. Sezawa mode SAW's with high phase velocities up to 5430 m/s and l arge electromechanical coupling coefficients up to 4.2% were found to propagate in ZnO/AlN/Si structure. The results could be useful for the further development of monolithic SAW devices integra;ted with Si ele ctronics.