Recent advancement in wireless communication requires substantial improvement in the performance of physical devices needed to implement ubiquitous, multi band, multi standard and reconfigurable radio frequency (RF) systems. Aluminum nitride contour-mode resonators have been proven as one of the most promising technologies for the implementation of fully-integrated single-chip transceivers, but remarkable efforts are still needed to be undertaken in order to improve the performance of RF MEMS filters, local oscillators and intermediate frequency (IF) filter stages. Investigations are required to understand and control the fundamental mechanisms that limit the resonator quality factor (Q), its electromechanical coupling coefficient and its stability behavior with respect to temperature fluctuations and ambient interactions. Higher Q devices will enable record low phase noise frequency reference oscillators for handsets, GPS and radar systems. Larger electromechanical coupling coefficients translate into low losses and large bandwidth filters with a reduction of the device count per function. The aim of this project is to investigate and optimize the ambient factors and fundamental material properties that impact the performance of AlN contour-mode resonators. Process fabrication optimization, measurement and simulation-based modeling for different temperatures and designs, and material analysis techniques (SEM, TEM, AFM, X-ray diffraction) have been extensively used to characterize and tailor the materials and device properties in order to obtain high-performance resonators.
Project end date: 02/03/09