臺灣博碩士論文加值系統

本研究使用原子層沉積法（Atomic Layer Deposition, ALD），在200~500℃沉積溫度下，以TiCl4和H2O為反應前驅物，在高摻雜n型矽基板以及Ta、Ti和Ni基板上成長TiO2薄膜，探討其成長速率、折射率、表面型態、薄膜結構以及光響應特性。
實驗結果顯示，各種基板上的TiO2薄膜成長速率幾乎不受製程溫度影響，約為0.05 nm/cycle；在結構方面，Si基板上成長的TiO2，在成長溫度400℃以下都是anatase相，500℃才有rutile相出現，然而在Ta及Ni基板上400℃就有rutile相出現，在Ti基板上rutile相出現的溫度更降低至300℃。表面型態方面，所有基板上成長的TiO2晶粒大小皆隨溫度變化而有一最小值；200℃成長的晶粒最大，300℃與400℃成長的晶粒最小，而500℃成長的晶粒又變大。光電化學特性方面，在Ti基板上成長的TiO2可以獲得最佳的光電流響應。為了成長出大顆晶粒和低缺陷密度的anatase相，本實驗利用二階段成長法，第一階段低溫成核，第二階段高溫釋放應力並成長，結果顯示二階段成長法，可在Si與Ni基板上獲得高品質anatase TiO2膜。

In this study, titanium dioxide (TiO2) films were grown on n+– Si、Ti、Ta and Ni substrates by atomic layer deposition (ALD) at 200~500℃ with TiCl4 and H2O as precursors The surface morphology, crystal structure, and photocurrent of TiO2 films were characterized by using SEM , XRD, and Potentiostat, respectively.
The results show that the growth rate was not affected by process temperature and substrate types. The XRD patterns demonstrate that on Si substrates the crystalline form is anatase at low deposition temperatures of 200~400℃ and is a mixture of anatase and rutile at 500℃. The mixture structure appears at 400℃ for Ta and Ni substrates and at 300℃ for Ti substrates. According to the surface morphologies, the change of grain size with process temperature was similar for all substrates. The grain size has a minimum at deposition temperature of 300~400℃. The photoelectrochemical properties of TiO2 deposited on Ti substrates are better than those on others. In order to grow an antase TiO2 film with large grain size and low defect density, a two-stage ALD with first stage for a nucleation layer and second stage for stress release and grain growth was proposed. The photoelectrochemical properties were improved on Si and Ni substrates by the two -stage deposition.

目　　錄
中文摘摘...............................................i
英文摘要...............................................ii
誌謝..................................................iii
目錄..................................................iv
圖目錄.................................................vi
表目錄.................................................x
第一章 前言............................................1
第二章 理論及文獻回顧...................................6
2-1 二氧化鈦的結構與性質............................6
2-2半導體光觸媒種類及氧化還原原理介紹.................8
2-3原子層化學氣相沉積TiO2之理論基礎..................11
2-4 ALD TiO2文獻回顧...............................16
第三章 實驗步驟.........................................17
3-1實驗流程規劃....................................17
3-2 ALD- TiO2系統設計及製作.........................18
3-3基板清洗........................................21
3-4 ALD- TiO2薄膜製備..............................22
3-5薄膜量測與分析...................................24
第四章 結果與討論........................................29
4-1基板種類對ALD TiO2薄膜特性之影響...................29
4-1-1成長速率...................................29
4-1-2折射率.....................................29
4-1-3薄膜表面型態................................32
4-1-4 薄膜結構..................................36
4-1-5光響應特性..................................40
4-1-6基板對ALD-TiO2薄膜特性總結與討論..............45
4-2 基板表面粗糙度對ALD TiO2薄膜特性之影響..............46
4-3 ALD-TiO2薄膜品質之進一步改良.......................50
4-3-1 n+ Si基板..................................53
4-3-2 Ni 基板.............................................60
4-3-3 Ta 基板.............................................63
4-3-4 Ti 基板.............................................66
4-3-5 ALD-TiO2薄膜改良結論.................................69
第五章 總結論..............................................70
參考文獻...................................................71

圖 目 錄
圖1-1、Honda-Fujishima effect.......................................2
圖1-2、各種半導體材料之能隙及其與H+/H2、H2O/O2氧化還原電位之相對位能圖.....3
圖1-3、本實驗室在AAO基板中沉積ALD二氧化鈦SEM圖..........................5
圖2-1、TiO2 anatase 與 rutile 結構相.................................6
圖2-2、半導體受光前及受光後之能帶隙能量變化與電子流動情形(a) n-型(b) p-型..9
圖2-3、分解有機物流程圖...............................................11
圖2-4、原子層化學氣相沉積製程順序，凸起部份表示閥門開啟時間...............12
圖2-5、ALD成長機制簡圖...............................................13
圖2-6、傳統CVD成長機制...............................................14
圖2-7、製程溫度對ALD薄膜成長速率之影響.................................15
圖3-1、實驗流程圖....................................................17
圖3-2、ALD TiO2系統設計圖............................................18
圖3-3、腔體示意圖....................................................19
圖3-4、恆溫區量測方式.................................................19
圖3-5、廢氣處理系統..................................................21
圖3-6、Ni基板表面型態，左為SEM，右為AFM量測圖...........................23
圖3-7、Ti基板表面型態，左為SEM，右為AFM量測圖...........................23
圖3-8、Ta基板表面型態，左為SEM，右為AFM量測圖...........................24
圖3-9、接觸角量測示意圖...............................................25
圖3-10、光電流分析架構圖..............................................28
圖3-11、光電流工作電極示意圖..........................................28
圖4-1、溫度對薄膜成長速率之影響，基板種類標示於圖上方....................30
圖4-2、溫度對薄膜折射率之影響.........................................31
圖4-3、Si基板上，各種製程溫度所成長之薄膜表面SEM影像，製程溫度標示於圖上...32
圖4-4、Ni基板上，各種製程溫度所成長之薄膜表面SEM影像，製程溫度標示於圖上...33
圖4-5、Ta基板上，各種製程溫度所成長之薄膜表面SEM影像，製程溫度標示於圖上...34
圖4-6、Ti基板上，各種製程溫度所成長之薄膜表面SEM影像，製程溫度標示於圖上...35
圖4-7、在Si基板上，各種製程溫度所成長TiO2薄膜結構之XRD繞射圖.............36
圖4-8、在Ni基板上，各種製程溫度所成長TiO2薄膜結構之XRD繞射圖.............37
圖4-9、在Ta基板上，各種製程溫度所成長TiO2薄膜結構之XRD繞射圖.............38
圖4-10、在Ti基板上，各種製程溫度所成長TiO2薄膜結構之XRD繞射圖............39
圖4-11、Si基板上成長的TiO2薄膜在UV光照射下的I-V特性曲線.................41
圖4-12、Si基板上成長的TiO2薄膜在UV-Vis光源照射下的I-λ特性曲線...........41
圖4-13、Ni基板上成長的TiO2薄膜在UV光照射下的I-V特性曲線.................42
圖4-14、Ni基板上成長的TiO2薄膜在UV-Vis光源照射下的I-λ特性曲線...........42
圖4-15、Ta基板上成長的TiO2薄膜在UV光照射下的I-V特性曲線.................43
圖4-16、Ta基板上成長的TiO2薄膜在UV-Vis光源照射下的I-λ特性曲線...........43
圖4-17、Ti基板上成長的TiO2薄膜在UV光照射下的I-V特性曲線.................44
圖4-18、Ti基板上成長的TiO2薄膜在UV-Vis光源照射下的I-λ特性曲線...........44
圖4-19、在常溫所成長Ni基板的表面型態，左為SEM圖，右為AFM量測圖...........47
圖4-20、在200℃溫度所成長的Ni基板表面型態，左為SEM圖，右為AFM量測圖......47
圖4-21、不同粗糙度Ni基板在300℃成長的二氧化鈦其表面型態SEM圖。(a)Ni基板(b)
Ni-rough基板...............................................48
圖4-22、不同粗糙度Ni基板在300℃成長的二氧化鈦薄膜XRD圖比較..............48
圖4-23、不同粗糙度的Ni基板上成長的TiO2薄膜I-V特性曲線..................49
圖4-24、不同粗糙度的Ni基板上成長的TiO2薄膜I-λ特性曲線..................49
圖4-25、一階段成長溫度的TiO2大晶粒成長過程............................50
圖4-26、二階段成長機制示意圖.........................................52
圖4-27、Si基板上200℃- 400℃二階段成長TiO2表面型態SEM圖。(a)200cycles-
800cycles，(b)300cycles-700cycles，(c) 400cycles-600cycles
左圖為低倍率；右圖為高倍率.....................................54
圖4-28、200℃搭配400cycles第一階段成長後的TiO2(a)表面型態SEM圖與(b)XRD圖
............................................................55
圖4-29、Si基板上200℃- 500℃二階段成長TiO2表面型態SEM圖。(a)200cycles- 800cycles，(b)300cycles-700cycles，(c)400cycles-600cycles，
左圖為低倍率；右圖為高倍率.....................................56
圖4-30、Si基板上二階段成長的薄膜XRD繞射圖，(a)為同圖4-27之試件，(B)為同圖4-
29之試片...................................................57
圖4-31、Si基板二階段成長TiO2薄膜的I-V特性曲線(a)200℃-400℃，(b)200℃-500℃
...........................................................58
圖4-32、Si基板二階段成長TiO2薄膜的I-λ特性曲線(a)200℃-400℃，(b)200℃-500℃
...........................................................59
圖4-33、Ni基板二階段成長TiO2表面型態SEM圖(a)150℃-400℃，(b)150℃-450℃
............................................................60
圖4-34、Ni基板二階段成長TiO2薄膜之XRD繞射圖............................61
圖4-35、Ni基板二階段成長二氧化鈦薄膜的I-V特性曲線.......................62
圖4-36、Ni基板二階段成長二氧化鈦薄膜的I-λ特性曲線.......................62
圖4-37、Ta基板二階段成長TiO2表面型態SEM圖(a)150℃-400℃，(b)150℃-450℃
............................................................63
圖4-38、Ta基板二階段成長TiO2薄膜之XRD繞射圖............................64
圖4-39、Ta基板二階段成長二氧化鈦薄膜的I-V特性曲線.......................65
圖4-40、Ta基板二階段成長二氧化鈦薄膜的I-λ特性曲線.......................65
圖4-41、Ti基板二階段成長TiO2表面型態SEM圖(a)150℃-400℃，(b)150℃-450℃
...........................................................66
圖4-42、Ti基板二階段成長TiO2薄膜之XRD繞射圖............................67
圖4-43、Ti基板二階段成長二氧化鈦薄膜的I-V特性曲線.......................68
圖4-44、Ti基板二階段成長二氧化鈦薄膜的I-λ特性曲線.......................68

表 目 錄
表2-1、二氧化鈦性質...................................................7
表3-1、四氯化鈦蒸汽壓與溫度關係........................................20
表3-2、水蒸汽壓與溫度關係.............................................20
表4-1、二階段成長參數條件.............................................52

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