玻璃基板上利用電子束蒸鍍法沉積氧化鋁薄膜作為高頻氧化鋅薄膜表面聲波元件之應用

Using e-beam evaporation to fabricate Al2O3 film on glass substrate for high frequency ZnO thin film SAW devices

張家齊(Chia-chi Chang)

指導教授 ： 吳慕鄉

大同大學/電機資訊學院/光電工程研究所/碩士(2010年)

摘要

隨著通訊元件朝高頻化發展，利用壓電基材之壓電換能特性的表面聲波元件已經廣受重視，使得具有高波速，高機電耦合係數，低插入損失等特性之表面聲波元件開發日漸重要。若能於低成本之基材之上成長壓電薄膜，再使用具有高聲速特性緩衝層所組合而成的表面聲波元件，不但可以對於元件操作頻率有所提升以及增加其機電耦合係數，更符合了節省成本此一重大商業取向，使得本研究更能符合現代講求輕薄短小的行動通訊產品之需求。

本研究在玻璃(Corning 7059)基板上，使用電子束蒸鍍法來沈積Al2O3薄膜作為高聲速緩衝層後，再製作指叉狀電極，然後使用射頻磁控濺鍍法來沈積ZnO薄膜作為壓電材料，比較在不同厚度的Al2O3薄膜之表面聲波元件頻率響應之變化，研究結果顯示在ZnO/IDT/Al2O3/Glass結構上隨著氧化鋁薄膜厚度增加時，波速會由2566.56 m/s提升至2823.48 m/s。研究結果證實以電子束蒸鍍法來沈積Al2O3薄膜可以取代藍寶石基板進而降低元件製作成本。

關鍵字

表面聲波元件 ； 氧化鋅

並列摘要

Now communication elements are developing towards high frequency. SAW devices must have high velocity, high electromechanical coupling coefficient and low insertion loss. SAW devices composed of the piezoelectric thin film and different substrate materials or buffer layers can improve the operating frequency of SAW devices. Consequently, SAW devices can be widely applied in mobile communication due to their small size and light weight.
This study employs Al2O3 thin film as the experimental buffer layer on glass (Corning 7059) substrate and ZnO film as the piezoelectric material to contrast the frequency responses of SAW devices. We use Al2O3 buffer layers with different thicknesses on the ZnO/Al2O3/glass structure. Successfully, the phase velocity of ZnO/IDT/Al2O3/Glass with Al2O3 thin film was increased from 2566.56 to 2823.48 m/s. The e-beam evaporated Al2O3 buffer layers with high velocity have been proved to lower the fabrication cost.

並列關鍵字

SAW devices ； ZnO

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