本篇論文主要探討利用超音波霧化熱裂解法沉積二氧化鈦應用於薄膜電晶體，在眾多沉積二氧化鈦薄膜製程中，我們選擇一種非真空環境下即可完成且低成本之製作方法：超音波噴霧熱烈解沉積法，並將此製程應用於薄膜電晶體之通道材料上，沉積於氧化錫摻雜氟的透明導電薄膜在玻璃基板上，同時也利用超音波霧化熱裂解法沉積氧化鋁作為閘極介電層，製作成底閘極結構的透明薄膜電晶體。
為了瞭解二氧化鈦結晶方向、結晶種類、表面粗糙度、晶粒大小、化學組成、氧空缺、折射係數、薄膜厚度，在本研究中使用(一) X-射線繞射分析、(二) 顯微拉曼光譜儀、(三) 原子力顯微鏡、(四) 掃描式電子顯微鏡、(五) 化學分析影像能譜儀、(六) 光致螢光光譜、(七) 橢圓偏光儀、(八) 穿透式電子顯微鏡。
在瞭解薄膜之材料分析後，將超音波噴霧熱烈解沉積技術應用於底閘極結構的透明薄膜電晶體上成長二氧化鈦之主動層和氧化鋁之介電層，分別以200oC、300oC以及400oC退火溫度去改善二氧化鈦薄膜電晶體之電子遷移率、次臨界擺幅、臨界電壓、最大輸出電流以及元件開關比，以400 oC退火的表現最佳，這是由於在高溫下進行退火有助於修復二氧化鈦表面之缺陷；綜合材料分析和電性分析，可以發現400oC退火溫度為本論文中的最佳參數。同時，我們使用濺鍍法沉積氧化銦鎵鋅作為參考的樣品，去探討氧化銦鎵鋅在底閘極結構的基本電性與材料分析。
我們將金屬氧化薄膜電晶體照射波長為320nm到450nm的光，探討電晶體照射光後所產生的光電流，與未照光的暗電流，分析金屬氧化薄膜光電晶體的紫外光響應和感測度，使用超音波噴霧熱烈解沉積技術沉積的二氧化鈦的光響應度較濺鍍法沉積的沉積氧化銦鎵鋅的光響應度的特性上相對優秀，以爐管400oC退火30分鐘的光響應最佳，顯示二氧化鈦在銳鈦礦的晶相，有著良好的對光感測度。因此，不論是在於一般的薄膜電晶體還是光電體上，使用超音波噴霧熱烈解沉積技術沉積的二氧化鈦的金屬氧化薄膜電晶體都有著具競爭力的表現。本論文中，超音波噴霧熱烈解沉積技術沉積技術不僅可以降低生產成本而且可以沉積出高品質的二氧化鈦薄膜，在未來工業的使用極具潛力。

The research mainly investigates on the TiO2-based metal oxide thin film transistors (TFTs) by using ultrasonic spray pyrolysis technique. Among TiO2 thin film deposition methods, ultrasonic spray pyrolysis deposition (USPD) which is a non-vacuum and low cost approach is used to fabricate the titanium dioxide active layer. Furthermore, this technique is applied to bottom-gate thin film transistors, including TiO2-based and IGZO based active layer.
In order to understand crystal phase, crystal type, surface roughness, grain size, chemical composition, oxygen vacancy, refractive index and thin film thickness of the oxide layer, the (1) X-ray Diffraction (XRD), (2) Microscopes Raman spectrometer, (3) Atomic Force Microscopy (AFM), (4) Scanning Electron Microscope (SEM), (5) Electron Spectroscopy for Chemical Analysis (ESCA), (6) Photoluminescence Spectrometer (PL), (7) Ellipsometry, and (8) Transmission Electron Microscopy (TEM) are adopted in this research.
After the material analysis of the TiO2 film, the USPD technique is used to grow the TiO2 active layer of the metal oxide TFTs and Al2O3 layer for gate dielectric of IGZO-based TFTs. To study the characteristics of the different annealing temperatures in TiO2-based TFTs, we choose 200oC, 300oC and 400oC annealing for 30 minutes to fabricate the devices. From the I-V characteristics of the metal oxide TFTs, it was found that maximum output current (IDS) increases with annealing temperature increasing. Among these electrical analyses, the anatase TiO2 TFT is effectively improved.
We also investigate the spectral response of metal oxide TFTs. From the I-V characteristics of photo current and dark current, we analyze the responsivity, R320/450 and external quantum efficiency (EQE). It was found that the photo response of the TiO2 film deposited by ultrasonic spray pyrolysis technique had the better performances than IGZO film deposited by sputter. Therefore, the TiO2 film deposited by ultrasonic spray pyrolysis technique had competitive performance in thin film transistor and phototransistor.
In summary, the USPD technique makes good quality of titanium dioxide in a cost-effective way, it is very promising technique to be used in the future industry.

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