| 研究生: |
許哲隆 Che-Lung Hsu |
|---|---|
| 論文名稱: |
以氮化鎵為基板之表面聲波元件之研製 The study of fabrication of surface acoustic wave devices on GaN based substrates |
| 指導教授: |
李清庭
Ching-Ting Lee |
| 口試委員: | |
| 學位類別: |
碩士 Master |
| 系所名稱: |
理學院 - 光電科學與工程學系 Department of Optics and Photonics |
| 畢業學年度: | 90 |
| 語文別: | 中文 |
| 論文頁數: | 78 |
| 中文關鍵詞: | 氧化鋅 、氮化鎵 、表面聲波 |
| 外文關鍵詞: | SAW, ZnO, GaN |
| 相關次數: | 點閱:14 下載:0 |
| 分享至: |
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論文摘要
本論文的研究內容為使用氮化鎵(GaN)做為基板材料,並以射頻式反應性濺鍍法(RF reactive sputtering)濺鍍氧化鋅(ZnO)壓電薄膜(Piezoelectric film)於氮化鎵基板上,再製作指叉狀電極轉換器(Interdigital transducer)於濺鍍出之基板上,以製作出的表面聲波元件(Surface acoustic wave device)來研究表面聲波在氮化鎵與氧化鋅所構成的壓電材料基板上所呈現出的特性。
首先我們使用濺鍍機(Sputter)將氧化鋅薄膜濺鍍於氮化鎵基板上,於濺鍍過程中改變濺鍍參數(入射射頻功率、反應室背景氣壓、氬氣與氧氣流量比例、、、等等),以找出適合於製作表面聲波元件之氧化鋅壓電薄膜之最佳濺鍍條件,包括高阻值(Resistivity)、良好的結晶性(Crystallinity)、高順向度(Preferred orientation)、單一c-軸指向性(c-axis orientation)與低的表面粗糙度(Surface roughness)。在經過一系列的嘗試後我們所得到的最佳濺鍍條件為入射射頻功率250W、系統中通入氬氣與氧氣氣體之總流量為20sccm、氧氣佔總流量比例之30﹪以及背景氣壓10mtorr。
實驗過程中我們使用X光繞射儀(XRD)以及原子力顯微鏡(AFM)分別來分析氧化鋅薄膜於氮化鎵基板上的結晶特性與平整度,由量測的結果我們發現由以上最佳濺鍍參數條件下沉積所得厚度約2μm之氧化鋅薄膜不但具有相當良好的結晶性,且呈現出單一垂直基板方向之c-軸指向性;在薄膜表面粗糙度的表現方面Rq(均方根值)值約僅有3nm,可說是十分適合用於製作表面聲波元件。
接著我們以一般半導體製程中之微影製程技術,製作指叉狀電極轉換器於濺鍍出的壓電材料基板上製作出表面聲波元件,並以網路分析儀量測表面聲波元件的特性,觀察元件的操作頻率與表面聲波的波速,並與其他相關的研究相互比較。我們所設計的指叉狀電極轉換器所產生的表面聲波波長為20μm,於氧化鋅/氮化鎵基板上所製作出之表面聲波元件量測到的聲波頻率約為322MHz,由此所得到之聲波波速約為6440m/s。
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