Results: 2021, 2020

The first stage of the SAWSAT project corresponds to Task. 1.1. Multiphysics piezo-electro-mechanical modeling of SAW resonators. The main result was the development of multiphysics models for the study of the propagation modes and the effect of superstrate layers. 2D multiphysics models of the surface acoustic wave (SAW) transducers were developed using the “Solid Mechanics” and “Electrostatics” modules, coupled through the “Piezoelectric Effect” module in COMSOL Multiphysics. A detailed analysis was performed in order to determine the propagation modes and resonance frequencies of transducers with 130 nm space and width and 80 nm metal thickness for four metallization types, namely titanium (Ti), gold (Au), aluminum (Al) and chromium (Cr). Additional studies were conducted on the effect of the metal layer thickness, GaN substrate thickness, as well as the effect of zinc oxide (ZnO), silicon dioxide (SiO2) and silicon nitride (Si3N4) superstrates.

 

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(a) 2D model developed in COMSOL multiphysics; (b) simulated results for the susceptance as a function of frequency for the Rayleigh propagation mode

 

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Von Misses stress distribution (color) and displacement field (arrows) at the resonance frequency for the Rayleigh propagation mode: (a) gold transducers @7.525 GHz; (b) aluminum transducers @7.02 GHz; (c) chromium transducers @6.479 GHz; (d) titanium transducers @6.777 GHz.

 

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Von Misses stress distribution (color) and displacement field (arrows) at the resonance frequency for the first order Sezawa propagation mode: (a) gold transducers @8.155 GHz; (b) aluminum transducers @8.176 GHz; (c) chromium transducers @8.121 GHz; (d) titanium transducers @8.148 GHz

All objectives of the 1^st Stage of the project were successfully accomplished.