藍寶石基底之多層壓電薄膜結構的表面聲波元件特性分析

Characteristics of Surface Acoustic Waves in Sapphire-based Multi-layer Piezoeletric Structure

歐祐呈(You-Cheng Ou)

指導教授 ： 羅如燕

義守大學/電機資訊學院/電機工程學系/碩士(2014年)

https://doi.org/10.6343/ISU.2014.00125

摘要

本論文針對表面聲波元件做特性分析，模擬元件是以藍寶石(Sapphire)為基底，搭配壓電材料所構成的多層壓電薄膜結構，如雙層結構ZnO/Sapphire、IDT/ZnO/Sapphire、ZnO/IDT/Sapphire，三層結構IDT/AlN/ZnO/Sapphire、AlN/ZnO/Sapphire 、AlN/IDT/ZnO/Sapphire，並利用有限元素法分析結構的波傳特性，在不同壓電材料厚度下對前三模態的表面聲波速度與機電耦合係數的影響，進而分析不同材料的金屬電極以及改變IDT於結構中的位置對多層壓電結構的影響。經過模擬並計算聲波特性後，可以發現雙層結構在(100)ZnO/(Cu)IDT/Sapphire結構的第二模態有最高的機電耦合係數，而三層結構則在(100)AlN/(Cu)IDT/(100)ZnO/Sapphire結構的第二模態有最高的機電耦合係數。

關鍵字

表面聲波 ； 藍寶石 ； 氧化鋅 ； 機電耦合係數

並列摘要

The purpose of this research was to investigate the propagation characteristics of surface acoustic waves (SAWs) in sapphire-based, multi-layer piezoelectric structures, which consist of two-layer structures such as ZnO/Sapphire, Interdigital transducers (IDT)/ZnO/Sapphire and ZnO/IDT/Sapphire; three-layer structures such as IDT/AlN/ZnO/Sapphire, AlN/ZnO/Sapphire and AlN/IDT/ZnO/Sapphire. The finite element method (FEM) was applied to analyze the effects of the thicknesses of piezoelectric films on the characteristics of SAWs. Phase velocities and coupling coefficients of the first three modes were calculated and presented. The effects of electrode materials as well as the positions of IDTs were also studies. Simulation results indicated that among the two-layer structures, the second mode of (100)ZnO/(Cu)IDT/Sapphire exhibited the highest coupling coefficient, while for the three-layer structures the second mode of (100)AlN/(Cu)IDT/(100)ZnO/Sapphire had the highest one.

並列關鍵字

surface acoustic wave ； Sapphire ； ZnO ； electromechanical coupling coefficient

參考文獻

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