Micromachined sensor array using thin film resonators

This paper describes the design, modeling and implementation of a microsensor array using aluminum nitride thin film resonators. A finite element method, formulated to accommodate the anisotropic and piezoelectric properties of aluminum nitride, is used to model acoustic wave coupling between resonators and to define the mask design. Two arrays on the same aluminum nitride membrane were fabricated using standard semiconductor processing. The measurements were in agreement with the modeling. A multilayer Mason model was applied to investigate the mass loading and viscoelastic effects via hydrogen absorption on the PdNi coated TFR. The preliminary H₂ sensitivity tests on a TFR hydrogen sensor are also presented.