本研究透過射頻磁控共濺鍍系統，使用氧化鋅搭配兩個不同比例的氧化銦鎢靶材，以沉積出不同的氧化銦鋅鎢薄膜，並且對薄膜特性與構造進行充分的分析與討論；再將此薄膜應用在電晶體、光感測器上。
在第一部分中，我們製備了氧化銦鋅鎢薄膜，過程中，除了改變共濺鍍的瓦數比外，再調整氬氣、氧氣流量比，最後進行了熱退火。接著，對其光學特性、表面結構及其元素進行了分析與討論。在光學特性分析中，所有參數製備出的薄膜無論在退火前後，在可見光波段中均表現出極高的穿透率，這表示此材料適合應用在顯示技術中。結構分析中，所有薄膜在經過退火後仍然保持非晶結構，薄膜的表面粗糙度方均根也得到改善。另外，在X射線光電子能譜分析中也可以發現，薄膜在經過退火後，其中的氧空缺比例明顯的下降；在濺鍍過程的氧通量比例提高時，氧空缺占比也會減少。
來到第二部分，我們將氧化銦鋅鎢薄膜應用在光感測器上，分別製作了不同通氧量，以及退火前後的光感測器進行特性的分析及討論。在通氧量的調整上，我們選擇了0%、4%、8%、12%來做比較，並且選擇攝氏200度的退火溫度。元件在退火前展現的特性較差，響應度不足，光暗電流比較小。在經過退火後，可以明顯地觀察到元件的光暗電流有明顯的上升，與此同時，其光暗電流比、光響應度以及拒斥比皆得到改善。但相對的，上升及下降飽和時間會有所衰退。在經過共10種參數的比較過後可以得到最佳參數為0%通氧退火的光感測器有最好的特性，擁有光暗電流4.23×10^2、光響應度5.42×10^(-1) (A/W)以及拒斥比1.62×10^3的性能。
第三部分即為本研究的研究重點，氧化銦鋅鎢薄膜電晶體。在此部分，我們使用了兩個比例不同的氧化銦鎢與氧化鋅製備的氧化銦鋅鎢薄膜以做比較及探討。在比例為In2O3:WO3 = 96:4的氧化銦鎢共濺鍍氧化鋅薄膜電晶體製備中，固定4%通氧量，並且調整共濺度瓦數比，最後進行攝氏200度的退火。可以得到的最佳參數為IWO/ZnO瓦數比80W/60W的薄膜電晶體，其開關電流比在退火後可以來到2.30×10^8，其餘參數也有不俗的表現。接著是比例In2O3:WO3 = 98:2的氧化銦鎢共濺鍍氧化鋅薄膜電晶體製備，通氧量的調整上，選擇了0%、4%、8%、12%以控制氧空缺的數量，改善元件特性，並且為了能與另一靶材充分比較，4%通氧量也有不同的共濺鍍瓦數比。同樣地，在製備完成後會進行攝氏200度的熱退火處理。可以得到的最佳元件為通氧4%且IWO/ZnO瓦數比60W/80W的薄膜電晶體，在非晶狀態下，場效遷移率可以達7.76(cm^2/Vs)，開關電流比2.15×10^8與次臨界擺幅0.31(V/decade)，表現出極好的開關特性。最後，為了更進一步優化元件特性，我們製備了使用高介電值材料氧化鋁作為介電層的薄膜電晶體，在更薄的氧化層厚度下，可以提高開電流，同時維持低暗電流，開關電流比可以達到1.3×10^11。最後，我們製備了氧化銦鋅鎢的光電晶體，在閘極電壓VG = 0時有最好的響應，其光暗電流比8.84×10^3，光響應度1.17×10^2 (A/W)，拒斥比5.15×10^3。

This study utilizes a radio frequency (RF) magnetron co-sputtering system with zinc oxide (ZnO) and two different ratios of indium tungsten oxide (IWO) targets to deposit various tungsten indium zinc oxide (WIZO) thin films. The characteristics and structures of these thin films are thoroughly analyzed and discussed. Subsequently, these films are applied to transistors and photodetectors.
In the first part of this study, we prepared WIZO thin films. During the process, in addition to varying the power ratio of co-sputtering, we also adjusted the argon and oxygen flow rates, followed by thermal annealing. Subsequently, the optical properties, surface structure, and elemental composition of the films were analyzed and discussed. In the optical properties analysis, all films, regardless of the parameters used in their preparation and whether before or after annealing, exhibited extremely high transmittance in the visible light wavelength. Structural analysis showed that all films maintained an amorphous structure even after annealing and the root mean square (RMS) surface roughness of the films also improved. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis revealed a significant decrease in oxygen vacancy ratio after annealing. Increasing the oxygen flow rate during the sputtering process also reduced the proportion of oxygen vacancies.
In the second part, we applied the WIZO thin films to photodetectors. We fabricated photodetectors with varying oxygen flow rates then analyzed their characteristics before and after annealing. The oxygen flow rates chosen for comparison were 0%, 4%, 8%, and 12%, with an annealing temperature of 200°C. The devices exhibited poor characteristics before annealing, with insufficient responsivity and low photocurrent-to-dark current ratios. After annealing, there was a noticeable increase in the photocurrent-to-dark current ratio, along with improvements in responsivity and rejection ratio. However, the rising and falling times for saturation slightly deteriorated. we found that the photodetector with 0% oxygen flow and annealed condition exhibited the best performance. This photodetector achieved a photocurrent-to-dark current ratio of 4.23×10^2, a responsivity of 5.42×10^-1 (A/W), and a rejection ratio of 1.62×10^3.
The third part, which is the focus of this research, concerns WIZO thin film transistors. In this section, we compared and discussed WIZO thin film transistors fabricated by two different ratios of indium tungsten oxide (IWO) co-sputtering with zinc oxide (ZnO). For the thin-film transistors fabricated with a ratio of In₂O₃:WO₃ = 96:4, we fixed the oxygen flow rate at 4% and adjusted the power ratio of the co-sputtering process, followed by annealing at 200°C. The optimal parameters were obtained with an IWO/ZnO power ratio of 80W/60W, achieving an on/off current ratio of 2.30 × 10^8 after annealing, along with commendable performance in other parameters. Next, for the thin film transistors fabricated with a ratio of In₂O₃:WO₃ = 98:2, we adjusted the oxygen flow rate to 0%, 4%, 8%, and 12% to control the number of oxygen vacancies and improve device characteristics. For a thorough comparison with the other target material, we also varied the co-sputtering power ratio at an oxygen flow rate of 4%. Similarly, the devices underwent thermal annealing at 200°C after fabrication. The best device was achieved with a 4% oxygen flow rate and an IWO/ZnO power ratio of 60W/80W. In its amorphous state, the device exhibited a field-effect mobility of 7.76(cm2/Vs), an on/off current ratio of 2.15 × 10^8, and a subthreshold swing of 0.31(V/decade), demonstrating excellent switching characteristics. Finally, to further optimize device performance, we fabricated thin-film transistors using aluminum oxide (Al2O3), a high-k material, as the dielectric layer. This approach enabled higher on-current and maintained low off-current with a thinner oxide layer, achieving an on/off current ratio of 1.3 × 10^11. We also fabricated WIZO phototransistors, which exhibited the best response at VG = 0, with a photocurrent-to-dark current ratio of 8.84 × 10^3, a responsivity of 1.17 × 10^2 (A/W), and a rejection ratio of 5.15 × 10^3.

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