title: Effects of compensating the temperature coefficient of frequency with the acoustic reflector layers on the overall performance of solidly mounted resonators.
abstract: Thin film acoustic wave resonator based devices require compensation of temperature coefficient of frequency (TCF) in many applications. This work presents the design and fabrication of temperature compensated solidly mounted resonators (SMRs). The characteristics of each material of the layered structure have an effect on the device TCF but depending on the relative position with respect to the piezoelectric material in the stack. The influence of material properties of the different layers composing the device on the TCF is discussed in detail. TCF behavior simulation is done with Mason's model and, to take into account the deterioration of overall performance due to the finite lateral size and shape of the resonator, we have used 2D and 3D finite element modelling of the resonators. The overall behavior of the device for external loads is predicted. SMRs are designed according to simulations and fabricated with different configurations to obtain TCF as near to zero as possible with an optimized response. Resonators are made by depositing Mo/AlN/Mo piezoelectric stacks on acoustic reflectors. As reflector materials, conductive W and insulating WOxfilms have been used as high acoustic impedance materials. SiO2films are used as low acoustic impedance material.
authors.affiliation: Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia. Electronic address: junaid_ij2000@yahoo.com.
authors.forename: Junaid
authors.initials: J
authors.lastname: Munir
authors.affiliation: GMME-CEMDATIC-ETSI de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
authors.forename: Teona
authors.initials: T
authors.lastname: Mirea
authors.affiliation: Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
authors.forename: Mario
authors.initials: M
authors.lastname: DeMiguel-Ramos
authors.affiliation: Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.
authors.forename: M A
authors.initials: MA
authors.lastname: Saeed
authors.affiliation: Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia.
authors.forename: Amiruddin
authors.initials: A
authors.lastname: Bin Shaari
authors.affiliation: GMME-CEMDATIC-ETSI de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Iborra
keywords: Acoustic reflectors; Finite Element Analysis; Solidly mounted resonators; Temperature coefficient of frequency