臺灣博碩士論文加值系統

近年來氧化鋅廣泛地被應用在表面聲波元件，它已經成功地被成長在quartz、Si、GaAs、sapphire基板上，其中成長sapphire基板更被廣泛的應用在高頻表面聲波元件，其主要原因為sapphire基板具有高聲速的之優點，然而由於sapphire基板價格較 Si 基板昂貴且不利於大面積化，在本研究中，我們成長ZnO在Diamond/Si上以達高頻表面聲波元件應用。
以鑽石相關材料為基底之表面聲波元件，在其元件之工作頻率已被證實其優越之特性。在本研究中，我們將探討不同型態之鑽石基板對元件波傳遞特性之影響。我們利用射頻磁控濺鍍法分別沉積ZnO薄膜於奈米鑽石（NCD）/Si與微米鑽石（MCD）/Si基板上，並製作成表面聲波元件。實驗結果顯示，其ZnO薄膜C軸優選方向之半高寬分別為0.21˚與0.23˚，薄膜表面平坦度分別為18.5 nm與9.3 nm，並利用網路分析儀量測元件之頻率響應，其IDT/ZnO/NCD/Si之第0模態之波速為5296 m/s（331 MHz），ZnO/IDT/NCD/Si之第1模態之波速為8960 m/s（448 MHz）。實驗所得結果與前人所作之理論分析結果相近。

Among recently developed piezoelectric thin film materials, ZnO has been considered to be very promising for fabricating thin film surface acoustic wave (SAW) devices. ZnO thin films have been deposited on quartz, Si, GaAs and sapphire substrates. In these substrates materials, sapphire is widely used for high frequency SAW device due to its high acoustic velocity. However, the sapphire substrate is more expensive than Si wafer, and it is still very difficult to grow large size of Al2O3 single crystal. In this study, we adopt the ZnO thin film on Diamond/Si substrate as a promising substrate for high-frequency SAW device.
Surface acoustic wave device built on diamond related substrates have been proven their superiority in working frequency. To evaluate the effects of diamond substrates for wave propagation, different thicknesses and types of diamond films, such as nanocrystalline diamond（NCD）and microcrystalline diamond（MCD）, are adopted in this study for comparison. The c-axis orientated ZnO films are sputtered on the NCD films and polished MCD films as the piezoelectric films. The experimental results show that the highly c-axis oriented ZnO films could be obtained. The full width at half maximum intensity（FWHM）of ZnO（002）films on NCD and MCD films obtained from the X-ray diffraction （XRD）were 0.21 ° and 0.23 °, respectively. The surface roughness of the ZnO films on NCD and MCD films was about 18.5 nm and 9.3 nm, respectively. It was found that the oth mode in the IDT/ZnO/NCD/Si structure has the velocity of 5296 m/s（331 MHz）, and the 1st mode in the ZnO/IDT/NCD/Si structure has the velocity of 8960 m/s（448 MHz）. The experimental results are in agreement with those published in the literatures.

致謝 i
英文摘要 ii
中文摘要 iv
目錄 v
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 2

第二章 基本理論 4
2.1 材料基本介紹 4
2.1.1 鑽石（Diamond）4
2.1.2 氧化鋅（ZnO）7
2.2 壓電特性與表面聲波元件之基本原理 9
2.2.1 正壓電效應 9
2.2.2 逆壓電效應 10
2.2.3 表面聲波元件基本原理 11
2.3 薄膜製作技術 15
2.3.1 射頻磁控濺鍍法 15

第三章 實驗製程與量測 22
3.1 基板準備 22
3.1.1 SiO2/Si 22
3.1.2 NCD/Si、MCD/Si 23
3.2 製備SiO2緩衝層 24
3.3 製備ZnO薄膜 25
3.4 薄膜物性量測 26
3.4.1 α-step 26
3.4.2 X-ray繞射儀 27
3.4.3 原子力顯微鏡 29
3.4.4 掃描式電子顯微鏡 30
3.4.5 拉曼光譜 31
3.5 表面聲波元件製作 31
3.5.1 IDT/ZnO/Substrate 32
3.5.2 ZnO/IDT/Substrate 34
3.5.3 表面聲波特性量測 36

第四章 結果與討論 38
4.1 NCD與MCD物性量測 38
4.2 SiO2緩衝層分析 46
4.3 ZnO/NCD/Si薄膜物性分析 48
4.4 ZnO/MCD/Si薄膜物性分析 51
4.4.1 沉積參數對薄膜結構之影響 51
4.5 ZnO/SiO2/MCD/Si薄膜物性分析 57
4.6 表面聲波元件特性量測 60
4.6.1 光罩設計 60
4.6.2 IDT/ZnO/NCD/Si 61
4.6.3 ZnO/IDT/NCD/Si 64
4.6.4 IDT/ZnO/MCD/Si、IDT/ZnO/SiO2/MCD/Si、ZnO/IDT/MCD/Si 67

第五章 結論 71
5.1 結論 71

參考文獻 73

表目錄
表1.1 Material characteristics of fabricated SAW devices 3
表2.1 鑽石基本特性 6
表2.2 氧化鋅基本特性 8
表2.3 壓電材料種類 9
表3.1 Silicon（100）基板規格 23
表3.2 SiO2薄膜沉積參數 25
表3.3 ZnO薄膜沉積參數 26
表3.4 表面聲波電極及圖案製作材料與設備 32
表4.1 ZnO薄膜製程參數 51
表4.2 表面聲波元件設計參數 60

圖目錄
圖2.1 鑽石晶體結構 5
圖2.2 ZnO 晶體結構 8
圖2.3 正壓電效應 10
圖2.4 逆壓電效應 11
圖2.5 表面聲波元件基本結構 12
圖2.6 典型表面聲波帶通濾波器之頻譜響應 15
圖2.7 RF濺鍍系統直流自我偏壓 20
圖2.8 RF阻抗匹配系統 21
圖3.1 射頻磁控濺鍍系統 24
圖3.2 α-step示意圖 27
圖3.3 X-ray diffraction示意圖 28
圖3.4 晶格繞射示意圖 28
圖3.5 原子力顯微鏡原理示意圖 29
圖3.6 掃描式電子顯微鏡基本構造圖 30
圖3.7 表面聲波元件上電極圖案製作流程 34
圖3.8 表面聲波元件下電極圖案製作流程 36
圖3.9 表面聲波濾波器特性量測系統架構圖 37
圖4.1 Illustration of ASTeX microwave CVD reactor 38
圖4.2 中國砂輪公司鑽石薄膜沉積專利技術 39
圖4.3 Nanocrystalline diamond（NCD）之拉曼量測圖 41
圖4.4 Microcrystalline diamond（MCD）之拉曼量測圖 41
圖4.5 不同厚度Nanocrystalline diamond（NCD）之SEM量測圖
（a）2.1 μm（b）3.6 μm（c）4.3 μm（d）5 μm 43
圖4.6 Microcrystalline diamond（MCD）之SEM量測圖 43
圖4.7 不同厚度Nanocrystalline diamond（NCD）之AFM量測圖
（a）2.1 μm（b）3.6 μm（c）4.3 μm（d）5 μm 45
圖4.8 Microcrystalline diamond（MCD）之AFM量測圖 46
圖4.9 ZnO/SiO2/MCD/Si之SEM量測圖 47
圖4.10 SiO2/MCD/Si之AFM量測圖 47
圖4.11 ZnO/NCD/Si之SEM量測圖 48
圖4.12 ZnO/NCD/Si之EDAX量測圖 49
圖4.13 ZnO/NCD/Si之XRD量測圖 50
圖4.14 ZnO/NCD/Si之AFM量測圖 50
圖4.15 ZnO薄膜沉積於MCD/Si基板之不同製程溫度XRD圖 52
圖4.16 ZnO薄膜沉積於MCD/Si基板之不同RF功率XRD圖 53
圖4.17 ZnO薄膜沉積於MCD/Si基板之不同Ar/O2流量XRD 54
圖4.18 ZnO薄膜沉積於MCD/Si基板之SEM圖 55
圖4.19 ZnO薄膜沉積於MCD/Si基板之AFM圖 55
圖4.20 ZnO薄膜沉積於MCD/Si基板之EDAX量測圖 56
圖4.21 ZnO/SiO2/MCD/Si之XRD量測圖 58
圖4.22 ZnO/SiO2/MCD/Si之AFM量測圖 58
圖4.23 ZnO/SiO2/MCD/Si之SEM量測圖 59
圖4.24 ZnO/SiO2/MCD/Si之EDAX量測圖 59
圖4.25 光罩示意圖 60
圖4.26 IDT線寬4μm之OM與頻率響應圖（IDT/ZnO/NCD/Si）62
圖4.27 IDT線寬4μm之OM與頻率響應圖（IDT/ZnO/SiO2/Si）62
圖4.28 IDT線寬5μm不同NCD緩衝層厚度之曲線圖（IDT/ZnO/NCD/Si）63
圖4.29 單晶鑽石表面聲波濾波器理論分析與奈米鑽石多晶鑽石表面聲波濾波器
實驗結果（IDT/ZnO/NCD/Si）63
圖4.30 IDT線寬5μm之OM與頻率響應圖（ZnO/IDT/NCD/Si）65
圖4.31 IDT線寬5μm不同NCD緩衝層厚度之曲線圖（IDT/ZnO/NCD/Si）65
圖4.32 單晶鑽石表面聲波濾波器理論分析與奈米鑽石多晶鑽石表面聲波濾波器
實驗結果（ZnO/IDT/NCD/Si）66
圖4.33 IDT/ZnO/NCD/Si（左）、ZnO/IDT/NCD/Si（右）之頻率響應圖
（IDT線寬5 μm、NCD厚度4.3 μm、ZnO厚度1.2 μm）66
圖4.34 機電耦合係數對kHZnO理論分析曲線圖IDT/ZnO/NCD/Si（左）
、ZnO/IDT/NCD/Si（右）67
圖4.35 IDT線寬5μm之OM與頻率響應圖（IDT/ZnO/MCD/Si）68
圖4.36 IDT線寬5μm之OM與頻率響應圖（IDT/ZnO/SiO2/MCD/Si）68
圖4.37 IDT線寬5μm之OM與頻率響應圖（ZnO/IDT/MCD/Si）69
圖4.38 波速對kHZnO理論分析曲線圖 69
圖4.39 機電耦合係數對kHZnO理論分析曲線圖ZnO/IDT/MCD/Si（左）
、IDT/ZnO/MCD/Si（右）70

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