Modeling, characterization and integration of thin film resonator microsensors

There is an increasing demand by using smart and miniaturized microsensors and microtransducers in the areas of automobile, environment Science and analytical chemistry. Thin film microresonators (TFRs), meriting from their small size, higher sensitivity and compatibility with VLSI process, have being investigated as microsensors. Gas or vapor absorbed species, or contacted liquids may perturb resonator mechanical, electrical and piezoelectric properties. In this dissertation, a coupled wave theory is presented and applied to analyze acoustic wave propagation phenomena both in TFR-solid and TFR-liquid phases. A two-dimensional analysis is implemented to compare with a one-dimensional model and experimental results. The analysis and characterization of polymer-coated TFR sensors are investigated, along with sensitivity and detection limit analysis. The experimental characterization of liquid-coated TFR sensors are also then investigated and discussed. In order to minimize temperature-induced drift and other possible geometrical and material mismatch, the design and implementation of a TFR microsensor array in which a differential approach was proposed have been demonstrated. The major challenge in the array design is to evaluate the wave crosstalks between individual TFRs and to investigate film mechanical strength in order to host multi-TFRs on a single substrate dice. General analytic EM design rules and numerical methods are used to model lateral wave coupling and assist the design of process masks. The processing and electrical measurements of TFR arrays are then investigated. The implementation and experimental characterization of a TFR polymer sensor array are finally presented and discussed