Finite element modeling and performance analysis of Surface Acoustic Wave (SAW) devices that are developed in CMOS (Complementary Metal Oxide Semiconductor) technology are presented. CMOS-SAW devices were designed, fabricated and characterized as a biosensor for breast cancer biomarker detection. A detailed 3D model with 18 CMOS layers and a structured finite element (FE) analyses methodology are laid out to extract the acoustic behavior of the substrate and the piezoelectric material of interest, zinc oxide (ZnO). A three-step analysis encompassing modal, harmonic and transient simulations is detailed. Experimental characterization results for the fabricated CMOS-SAW devices with operating frequency of 322.7 MHz show close agreement to the FE simulations with only 0.8 % deviations for operation frequency. Displacement and stress/strain maps for wave propagation are also presented. The results demonstrate that commercial FEM toolsets can provide valuable insight into understanding acousto-electric interactions and wave characteristics or can readily be used for accurate design parameter extraction through reliable pre-fabrication simulation of SAW device performance.