Spurious Suppression without Energy Dissipation in Aluminum--Nitride-Based Thin-Film Bulk Acoustic Resonator Using Thin Ring on Electrode Edge

We examined the suppression of spurious responses beneath the resonant frequency in an aluminum-nitride-based thin-film bulk acoustic resonator (FBAR) by a two-dimensional (2D) finite element method (FEM) and dispersion analysis of waves. The results confirmed that the 0th-order asymmetric mode ($A_...

Full description

Saved in:
Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 51; no. 7; pp. 07GC11 - 07GC11-5
Main Authors Hara, Motoaki, Kuwano, Hiroki
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.07.2012
Online AccessGet full text

Cover

More Information
Summary:We examined the suppression of spurious responses beneath the resonant frequency in an aluminum-nitride-based thin-film bulk acoustic resonator (FBAR) by a two-dimensional (2D) finite element method (FEM) and dispersion analysis of waves. The results confirmed that the 0th-order asymmetric mode ($A_{0}$ mode) influences the resonance characteristics. As a result of these findings, we propose a structure having a thin ring on the electrode edge to take advantage of this $A_{0}$ mode in suppressing spurious responses.
Bibliography:Influence of spurious responses in a ladder-type filter. Schematic illustration of the cavity-type FBAR. FEM model of the FBAR: (a) basic model and (b) multistep structure. Equivalent circuits of the FBAR. Relationship between the quality factors and the electrode size $W$. Characteristics of the multistep structure. Dispersion diagram of the FBAR: (a) calculation model and (b) calculated diagram. FEM model of proposed structure. Characteristics of the proposed structure. Characteristics of respective models. $Q_{\text{rl}}$ for the multistep and proposed structures. $Q_{\text{arl}}$ for the multistep and proposed structures. $\mathit{SR}_{3}$ for the multistep and proposed structures.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.51.07GC11