臺灣博碩士論文加值系統

本論文探討在照射過伽瑪射線的z-cut鈮酸鋰基板，以質子交換與濕式蝕刻法製作脊形結構，並利用此結構製作馬赫任德電光調變器。為瞭解脊形結構之改善情形，本研究採用表面輪廓儀與電子顯微鏡量測脊形結構的外觀比；實驗數據顯示，在照射過伽瑪射線的鈮酸鋰基板上製作的脊形結構的縱深增加了約30%，外觀比改善了87%。又因為脊形結構之側壁較為垂直，亦加強了光場的侷限性，使得半波電壓由7.9V降為6V，改善幅度約為31%。

In this thesis, ridge Mach-Zehnder modulator is successfully fabricated by using proton exchange wet etching in gamma ray irradiated z-cut lithium niobate. To characterize the effect of gamma ray irradiation, the depth and the aspect ratio of the ridge structure are measured by surface profiler and electron microscope. Experimental results show that the depth and the aspect ratio of the gamma ray irradiated ridge structure are increased by about 30% and 87%, respectively. Owing to deeper vertical side walls, the optical field confinement is enhanced and the drive voltage is decreased from 7.9V to 6V.

中文摘要 I
英文摘要 III
表目錄 VIII
圖目錄 IX
第一章 緒論 1
1-1 研究背景 1
1-2 研究動機 3
1-3 內容簡介 4
第二章 研究方法 5
2-1 研究目標與架構 5
2-2 鈮酸鋰簡介 5
2-2-1材料特性 5
2-2-2光學特性 7
2-2-3光波導製作 9
2-3 伽瑪射線簡介 11
第三章 脊形光波導製作與特性 14
3-1 脊形光波導 14
3-2 蝕刻法與質子交換原理簡介 15
3-2-1常見的蝕刻方法 15
3-2-2質子交換 16
3-3 實驗過程 19
3-3-1製作流程 19
3-3-2脊形外觀與實驗結果討論 23
3-4 影響重疊積分值之因素 27
3-4-1脊形寬度 27
3-4-2脊形傾斜角度 28
3-4-3脊形深度 29
3-4-4波導偏移 30
3-4-5電極間距 32
第四章 馬赫任德電光調變器 35
4-1電光調變器原理簡介 35
4-2 元件製作過程 42
4-2-1元件設計 42
4-2-2製程步驟 44
4-2-2-1伽瑪射線照射 45
4-2-2-2晶片切割 45
4-2-2-3微顯影術 46
4-2-2-4金屬鍍膜 47
4-2-2-5掀離法與蝕刻法 48
4-2-2-6質子交換 49
4-2-2-7濕式蝕刻 49
4-2-2-8高溫擴散 49
4-2-2-9研磨拋光 50
4-3量測系統 50
4-4 製程討論與量測結果 52
4-4-1鉭金屬遮罩 52
4-4-2緩衝層 53
4-4-3光場量測 55
4-4-4調變訊號量測 56
第五章 結論與未來展望 58
5-1結論 58
5-2未來展望 59
參考文獻 60
中英對照



表目錄
表 2-1 鈮酸鋰晶體的基本特性 6
表 2-2 輻射相關單位表 13
表 2-3 鈷-60照射場劑量率表 13
表 3-1 常用的質子交換酸源基本性質 18
表 3-2 脊形外觀比 25



圖目錄
圖 2-1 (a)在居里溫度以下，晶體呈鐵電性 7
(b)在居里溫度以上，晶體呈順電性
圖2-2 伽瑪射線儀器 12
圖3-1 質子交換示意圖 17
圖3-2脊行結構製程步驟示意圖 19
圖 3-3 質子交換8小時，隨時間增加之脊形深度變化圖 24
圖3-4 以白光干涉儀量測脊形深度之結果 26
圖3-5 以電子顯微鏡量測其脊形側壁圖 26
圖3-6 脊形寬度對重疊積分值之影響 28
圖3-7 脊形斜率對重疊積分值的影響 29
圖3-8 脊形斜率對重疊積分值的影響 30
圖3-9 各種波長在不同寬度之脊形上偏移對重疊積分值之影響 31
圖3-10 z-cut鈮酸鋰電光調變器之結構示意圖 32
圖3-11 Alferness計算z-cut無脊形電光調變器之重疊積分值 32
圖3-12 鈮酸鋰脊形電光調變器之電極結構示意圖 33
圖 4-1 馬赫任德電光調變器之結構圖 36
圖 4-2 馬赫任德電光調變器之電極及電場示意圖 40
圖 4-3 推挽式電極及電場示意圖 41
圖4-4 光罩設計 43
圖4-5 實際製作之元件參數 43
圖4-6 電光調變器製程流程 44
圖4-7 光場量測架構 51
圖4-8 調變量測架構 51
圖4-9 鉭金屬厚度，對掀離結果之影響 53
圖4-10 緩衝層對電極的影響 54
圖4-11 緻密度且均勻度佳的表面製作出來的電極 55
圖4-12 馬赫任德電光調變器光場圖 56
圖4-13 不對稱之光訊號量測圖 57
圖4-14 馬赫任德電光調變器實驗量測圖 57

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