title: Characteristics of MgxZn1-xO thin film bulk acoustic wave devices.
abstract: Piezoelectric thin film zinc oxide (ZnO) and its ternary alloy magnesium zinc oxide (MgxZn1-xO) have broad applications in transducers, resonators, and filters. In this work, we present a new bulk acoustic wave (BAW) structure consisting of Al/MgxZn1-xO/n(+)-ZnO/r-sapphire, where Al and n+ type ZnO serve as the top and bottom electrode, respectively. The epitaxial MgxZn1-xO films have the same epitaxial relationships with the substrate as ZnO on r-Al2O3, resulting in the c-axis of the MgxZn1-xO being in the growth plane. This relationship promotes shear bulk wave propagation that affords sensing in liquid phase media without the dampening effects found in longitudinal wave mode BAW devices. The BAW velocity and electromechanical coupling coefficient of MgxZn1-xO can be tailored by varying the Mg composition, which provides an alternative and complementary method to adjust the BAW characteristics by changing the piezoelectric film thickness. This provides flexibility to design the operating frequencies of thin film bulk acoustic wave devices. Frequency responses of devices with two acoustic wave modes propagating in the specified structure are analyzed using a transmission line model. Measured results show good agreement with simulation.
authors: School of Engineering, Rutgers University, Piscataway, NJ 08854, USA.
authors: Richard H
authors: RH
authors: Wittstruck
authors: Xiaojun
authors: X
authors: Tong
authors: Nuri W
authors: NW
authors: Emanetoglu
authors: Pan
authors: P
authors: Wu
authors: Yimin
authors: Y
authors: Chen
authors: Jun
authors: J
authors: Zhu
authors: Sriram
authors: S
authors: Muthukumar
authors: Yicheng
authors: Y
authors: Lu
authors: Arthur
authors: A
authors: Ballato
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D003198:Computer Simulation; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017616:Magnesium Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008956:Models, Chemical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D015034:Zinc Oxide / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D017616:Magnesium Compounds; D015034:Zinc Oxide