Study On AlN Thin Piezoelectricity Film And Simulation Of Film Bulk Acoustic Resonator Filter

FBAR filter with miniaturized, high Q,high frequency，high power capacity andintegration etc,are the next generation filter of replacing SAW filters. The FBAR filters areRF filters which are most likely to achieve RF module fully integration.Based on the basic principles of FBAR resonator, the element studied impedance ofAlN-based FBAR unit under different electromechanical coupling coefficients, andsimulated frequency charareristic of the device of different electrode thickness corrections.Establishing Mason model of Au-AlN-Mo’s FBAR unit, based on the model and the mostsimple ladder-type filter structure we researched difference of the filter performance asseries-parallel FBAR unit section area ratio and the number of cascaded unit change.We hasgot five cascaded structure filter with good transmission performance, then make the AlNdielectric loss introduce Mason model to re-examine the five cascaded filter transmissioncharacteristics. It was further optimized, and we ultimately got a good performance of theFBAR filter. Finally, we studied transmission characteristics of the FBAR filter withdielectric loss as electromechanical coupling coefficient changes,got allowable range ofelectromechanical coupling coefficient, which provide guidance for the reasearch of highlyoriented piezoelectric aluminum nitride thin film.Through the guidance of the simulation results of FBAR filter, we carried out a studyof AlN films, and obtainaluminum nitride film with a rocking curve FWHM of4.5°, whichhave a rough estimate of its electromechanical coupling coefficient of5%which meet theFBAR filter requirements. At the same time, we expanded our work which include study ofthe film surface roughness, composition and surface-interface morphology of AlN films,wehave visual representation of the C-axis oriented AlN thin film.