Active area optimisation of film bulk acoustic resonator for improving performance parameters

Abstract

In this Letter, an active area optimisation technique to improve the performance parameters of the film bulk acoustic resonator (FBAR) is proposed. The active area of the back trench membrane‐based FBAR is optimised to remove the spurious modes, higher harmonic modes, and to confine the acoustic signal at its central part during the resonance. The effect of thickness variation of SiO2 layer on the performance parameters was studied using finite‐element analysis (FEA) simulation. The SiO2 film, on silicon substrate, was used as the support layer and zinc oxide was used as the piezoelectric film for the resonator. The authors have successfully demonstrated the FBAR through FEA for an optimised active area of 320 × 320 µm2, series resonance frequency (f s ) 1.249 GHz, and parallel resonance frequency (f p ) 1.273 GHz with an effective electromechanical coupling coefficient false(keff2false) of 4.65%.

Influence of Homo- and Hetero-Junctions on the Propagation Characteristics of Radially Propagated Cylindrical Surface Acoustic Waves in a Piezoelectric Semiconductor Semi-Infinite Medium

“…With the popularization of fifth-generation communication equipment and the realization of the interconnection of everything, piezoelectric materials, such as aluminum nitride (AlN), zinc oxide (ZnO), gallium nitride (GaN), and PZT, are being increasingly used in bulk acoustic wave (BAW) or surface acoustic wave (SAW) resonators, including film bulk acoustic resonators [1][2][3][4], solidly mounted resonators [5]. Some of these practical applications are closely related to the propagation characteristics of SAW in piezoelectric materials.…”

“…Since the dispersion and attenuation characteristics of cylindrical SAW are independent of the radial coordinate, the mathematical models in this paper provide theoretical guidance for studying the propagation characteristics of other types of SAW in PSC materials, such as the Rayleigh-type SAW. Since the influence of the homo-and hetero-junctions mainly concentrates on the attenuation characteristic of SAW, the discussion in this paper provides theoretical guidance for the design and manufacture of SAW resonators [3,4], energy harvesting [6,7], and acoustic wave amplification [8]. Due to the interface characteristic lengths, the first mathematical model is more complex than the second.…”

New Shear Horizontal (SH) Surface-Plasmon-Polariton-like Elastic Surface Waves for Sensing Applications

“…Another advantage of the proposed new SH elastic surface waves is the fact that they have only one component of the mechanical displacement (along axis ), which is completely uncoupled with the remaining components of mechanical vibrations, such as longitudinal (L, along axis ) and shear vertical (SV, along axis ). Multimodal coupling may be a significant problem in conventional bulk ultrasonic devices [ 16 , 17 ].…”

Influence of the Schottky Junction on the Propagation Characteristics of Shear Horizontal Waves in a Piezoelectric Semiconductor Semi-Infinite Medium

“…Only the biasing electric field parallel to the Schottky junction can provide evident influence on the attenuation characteristic of shear horizontal waves and enhance the influence of the Schottky junction; adjusting the biasing electric field can regulate attenuation characteristics of shear horizontal waves and optimize the acoustic characteristics of energy harvesters formed by PSC semi-infinite medium Since the influence of the Schottky junction mainly concentrates on the attenuation characteristic of the shear horizontal wave, the discussion in this paper provides theoretical guidance for the design and manufacture of SAW resonators, energy harvesters, and acoustic wave amplifications [29,30]. Through the first mathematical model and the interface characteristic length, we might consider the propagation characteristics of shear horizontal waves in more complex PSC materials in subsequent work, such as the PSC layered composite structures containing multi-layer Schottky junctions.…”