Study of Spatial Distribution of Piezoelectric Properties of ZnO Films by Acoustic Resonator Spectroscopy
- PDF / 822,747 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 16 Downloads / 141 Views
ICAL PROCESSES IN ELECTRON DEVICES
Study of Spatial Distribution of Piezoelectric Properties of ZnO Films by Acoustic Resonator Spectroscopy S. G. Alekseeva, *, V. A. Luzanovb, and N. I. Polzikovaa aKotelnikov
Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow, 125009 Russia Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino Branch, Fryazino, 141190 Russia *e-mail: [email protected]
bKotelnikov
Received June 12, 2020; revised June 12, 2020; accepted June 20, 2020
Abstract—Using broadband acoustic resonator spectroscopy, an almost twofold increase in the frequency of optimal excitation of the composite microwave resonator of shear bulk acoustic waves is found when the distance from the substrate to the magnetron axis during the deposition of a ZnO film by magnetron sputtering is changed. The frequency characteristics of the resonator structure are simulated and an explanation of the change in the optimal excitation frequency by the inhomogeneity of the inclination of the ZnO film texture’s axis over the thickness is proposed. DOI: 10.1134/S1064226920110017
INTRODUCTION Bulk acoustic wave (BAW) resonators with piezoelectric (PE) films as transducers, as well as filter structures based on them, find applications in telecommunications, radar, sensor, and other systems due to their small size, low power consumption, and high Q-factor in the gigahertz frequency range [1–4]. In recent years thin-film PE transducers of microwave BAWs have also been in high demand as a source of coherent phonons for fundamental and applied research in the fields of quantum acoustodynamics, microwave magnetic straintronics, phononics, etc. [5–7]. A thin-film transducer is a PE layer (ZnO, AlN, PZT, etc.) with a thickness from fractions to several microns, placed between thin-film metal electrodes, to which a microwave voltage is applied. The transducer depending on the direction of the piezoactive axes can excite BAWs with the polarization parameter of elastic displacement. For applications in microwave filters, piezoelectrics with a polar axis directed along the normal to the film are required, with the help of which longitudinal BAWs (with elastic polarization also directed along the normal), are excited. However, to solve some problems, the use of shear waves is required, for the excitation of which the deposition of PE films with the axis of PE texture inclined at a certain angle to the normal is necessary [8]. Among such tasks is the development of highly sensitive gravimetric sensors for operation in a liquid medium [4], in which longitudinal waves experience significant attenuation, so their application is difficult. The possibility of PE
excitation of shear BAWs is of interest for the development of magnetic sensors, controlled or switched by electric and (or) magnetic fields magnetoelectric hybrid microwave structures (filters, phase shifters, etc.), and also for studying the properties of new materials and structures, including the interaction of transverse p
Data Loading...
