| The wireless industry, especially the mobile applications has rapidly grown with the maturity of Si integrated technologies. Increasing innovative applications demand newer technologies or novel processes and, at the same time should integrate with existing standard Complementary Metal-Oxide-Semiconductor (CMOS) technology. Bulk Acoustic Wave (BAW) resonators form core elements in highly advanced Radio frequency (RF) front end and radio modules. They are of prime importance due to their small size and low loss. Their impact on radio frequency and sensing systems has motivated the development of new innovative applications.;The principle of acoustic resonance at Gigahertz frequencies is achieved using Thin Film Resonators (TFRs). They are manufactured in CMOS foundry for low cost batch fabrication and potential integration with other integrated circuitry. Accurate modeling of the electrical performance of these RF-MEMS (Microelectromechanical Systems) resonators depends on how precisely the values of physical parameters of the materials used in its design are known and if all the requirements have been met. Hence this Ph.D. dissertation addresses these sophisticated designing, fabrication and characterization aspects.;During our industrial productions of these resonators it was found that these parameters generally vary from one material manufacturer to another and the processing methods used during fabrication. Hence a method is also demanded to determine these values based on resonator's electrical measurements. We have developed a simple, quick, and inexpensive method to determine the effective acoustic velocity and density values of the materials used in the resonator. The experiment comprises of generating various electrical impedance peaks in the wideband spectrum of the resonator that are material sensitive and correlate to the acoustic properties of the structure. The same resonators were tested and matched over temperature variations to generate information for the extraction of their temperature coefficients of frequency as well. The materials used in our experiment were Silicon Dioxide (SiO2), Molybdenum (Mo), Aluminum Nitride (AlN), Tungsten (W) and Aluminum Copper (AlCu). |
