本文利用射頻磁控濺鍍法沉積非晶型氧化鋅鈦銦薄膜，並討論在不同製程條件下薄膜的特性，接著將薄膜應用於氣體感測器與紫外光活化感測器，進而分析薄膜參數對氣體反應特性之影響。現有的相關研究多著重於量測時導電率的變化，我們希望以理論更加深入地探討氣體感測的相關機制。另一方面，本研究也利用先前完成之非晶型氧化銦鎵鋅薄膜電晶體，來探討閘極偏壓與氣體感測行為間的關係。
第一部分我們用磁控濺鍍的方式在不同氧分壓的製程條件下進行薄膜沉積，並分別探討氧化鋅鈦銦薄膜其光學特性、薄膜表面/縱深結構分析與薄膜組成分析。在光學特性方面，結果顯示薄膜在可見光區有80%以上的高穿透率，而換算能隙後約為4eV，是一寬能隙材料。在薄膜表面/縱深結構分析結果方面，氧化鋅鈦銦薄膜因使用磁控濺鍍而沉積得相當均勻且呈現非晶型態，利用AFM表面分析可以看出薄膜表面粗糙度會受到製程中氧流量影響; 薄膜組成分析上，我們藉由X射線光電子能譜（XPS）也可以發現，薄膜中的氧空缺會因為製程中的氧流量越大而逐漸減少。
在實驗的第二部分，我們將氧化鋅鈦銦薄膜應用於氣體感測器來檢測乙醇、丙酮、異丙醇、一氧化碳以及二氧化硫等氣體，透過改變濺鍍氧通量與指叉狀上電極之金屬材料來比較其對於氣體感測特性的影響，並利用紫外光照射活化降低操作溫度。當氧流量提高時，基於化學吸附理論、缺陷理論與表面粗糙度的提升，元件氣體感測靈敏度也隨之提高，其中在氧分壓10%製作下的元件對於500ppm的乙醇響應更高達2000%以上，並擁有良好的選擇性及再現性。當選擇電極材料時，由於蕭特基接觸與能障的影響，越低的金屬功函數(大於薄膜能隙4eV)，會使得元件氣體感測響應值提高，其中金屬電極為鎳/金結構的元件由於功函數最低再加上金的催化，其對於氣體感測的響應最高。此外，我們也探討氧化鋅鈦銦氣體感測器於紫外光照射活化之下所造成的影響，經由紫外光照射後的元件均能有效將操作溫度由300°C降低至150°C。
實驗的最後，我們利用先前完成之濺鍍氧流量1%的氧化銦鎵鋅薄膜電晶體，以實現三端量測氣體感測器，透過改變閘極偏壓來控制其對乙醇的響應值並且討論該元件對氣體反應特性的影響。

In this thesis, indium titanium zinc oxide (InTiZnO) thin films are prepared by RF magnetron sputtering system and their film properties are discussed thoroughly under different processing ambiences. Then we will apply the InTiZnO thin films to fabricate gas sensing applications. On the other hand, we utilize the Indium gallium zinc oxide (IGZO) thin film transistors (TFTs) to realize a FET gas sensor. Most of the previous research just focus on the variation of conductivity. In this study, we will investigate the factors that influence the surface reactions and also discuss the parameters of gas sensing mechanism in detail.
In the first part of the experiment, InTiZnO films are deposited under different oxygen partial pressure ratio and investigate into optical, surface/depth and element analysis. From the optical analysis, the transmittance in the visible region can achieve more than 80% and the corresponding energy bandgap is about 4eV. In the surface/depth structural analysis results, the InTiZnO thin films are uniformly deposited by sputtering and exhibit an amorphous state. It can be seen from the AFM analysis that the surface roughness of the film is affected by the oxygen flow during the process. We can also find that the oxygen vacancies in the film are reduced due to the increase of oxygen flow by XPS.
In the second part of the experiment, InTiZnO gas sensors are fabricated to detect harmful gases such as ethanol, acetone, isopropanol, carbon monoxide, and sulfur dioxide. We will discuss their gas sensing properties by changing the oxygen flow ratio and the metal materials of the interdigitated electrodes. Besides, we will use UV irradiation to reduce the operating temperature. When the oxygen flow ratio increases, based on chemical adsorption model, defect theory and surface roughness, the sensitivity of the device also increases. Among them, the device fabricated under 10% oxygen partial pressure has the highest sensitivity, which is over 2000% and with good selectivity and reproducibility. When selecting the electrode materials, the lower metal work function will increase the gas sensing response because of the Schottky contact and its barrier height. Therefore, the device with Ni/Au electrode has the highest responsivity due to the lowest work function and catalysis by gold. In addition, we can effectively reduce the operating temperature from 300°C to 150°C by utilizing the UV irradiation.
At last, we have demonstrated three-terminal gas sensing with Indium gallium zinc oxide (IGZO) thin film transistors. The gate bias change is used as a sensing parameter to detect ethanol vapor.

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