噴射式大氣電漿系統沉積鎵摻雜氧化鋅薄膜之傾斜角及軌跡效應研究與雷射導引加熱系統之架設測試

Oblique Angle and Trajectory Effect of Ga-doped ZnO Film Deposited by Atmospheric Pressure Plasma Jet System and Test of Laser-assisted APPJ System

陳文凱(Wen-Kai Chen)

指導教授 ： 莊嘉揚

國立臺灣大學/工學院/機械工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803895

摘要

目前工業界普遍以錫摻雜氧化銦(Indium tin oxide, ITO)作為透明導電薄膜的主流材料。但由於銦屬於稀有金屬，且其價格在近年來不斷攀升。因此許多研究團隊正積極地尋找替代材料。其中，鎵摻雜氧化鋅(Gallium-doped zinc oxide, GZO)為近年來相當受到矚目的材料之一。本研究使用本團隊自行架設之噴射式大氣電漿(Atmospheric pressure plasma jet, APPJ)系統沉積鎵摻雜氧化鋅薄膜，其主要優點是在大氣環境即能沉積薄膜，免去昂貴的真空腔體設備費用，且能透過漸進式柵形掃描(Raster scanning)在大面積基板上沉積薄膜。
近年來曲面顯示器與穿戴式裝置發展迅速，而大面積的曲面基板可以視為由一連串小角度傾斜的平面所組成。因此，若想利用噴射式大氣電漿在曲面基板上沉積薄膜，傾斜角造成之效應必然是關鍵影響因子之一。本研究更新前人之優化實驗參數，針對自行架設的APPJ系統探討基板傾斜角(Oblique angle)與掃描軌跡(Trajectory)對APPJ系統沉積薄膜品質的影響。首先，我們改良設備架構以滿足基板傾斜實驗需求，並在固定沉積時間的情況下，分別探討單、雙次沉積使用不同軌跡造成之效應。藉由雙次沉積試片量測結果，發現了基板傾斜所產生的偏向氣流效應，會明顯影響薄膜品質。接著對單次沉積進行更詳細的討論發現掃描方向由基板上游掃到下游時，薄膜品質會受到偏向氣流效應影響而變差，且當傾斜角增加、掃描步進減少時，惡化情況會更加嚴重。然而，若掃描方向是由下游掃到上游，薄膜各項品質卻會與無傾斜角之標準試片非常接近，且傾斜角與掃描步進的改動對薄膜品質影響很小，代表使用此掃描方向能夠大幅降低偏向氣流效應的影響。藉由量測結果，我們發現偏向氣流會造成薄膜的大型顆粒微結構數量增加、表面粗糙度上升、主要結晶面數量增加、薄膜緻密程度減小、鎵與氧鍵結比例增加、增強材料擴散效應等現象而使薄膜品質劣化，此結論也為使用APPJ在曲面基板沉積薄膜之研究提供了重要資訊。
最後，我們架設了雷射輔助大氣電漿系統，以滿足進行雷射薄膜沉積相關研究之需求，嘗試使用雷射取代加熱吸盤對基板進行局部加熱，使我們無須使用微影蝕刻製程就能沉積出特定圖樣之透明導線。我們分別使用藍紫光與二氧化碳雷射源聚焦在玻璃與聚亞醯胺基板進行加熱測試，測試與評估使用雷射加熱的設置方式與其可行性。

關鍵字

噴射式大氣電漿 ； 鎵摻雜氧化鋅 ； 傾斜角效應 ； 軌跡效應 ； 曲面基板 ； 雷射加熱

並列摘要

Indium tin oxide (ITO), a transparent conductive oxide (TCO) material, is widely used today in various industries. However, many researchers are dedicated to find alternative materials to replace ITO, since the cost of Indium has been rising for many years due to its scarcity. Among these alternatives, Gallium-doped zinc oxide (GZO) has drawn much attention lately. Our research group established our own atmospheric pressure plasma jet (APPJ) system which enabled us to deposit GZO thin films on the the large-area glass substrate with raster scanning trajectory in atmospheric environment, and spared us the high expense of applying vacuum equipment.
In recent years, the development of curved displays and wearable devices has been advancing rapidly. Curved substrates with large surface area can be treated as a composition of a series of small plates tilted in small angles. Therefore, the effects of tilted angles may play crucial rules in the APPJ-based film deposition on the curved substrate. In this presently study, based on the optimized experimental parameters established from our previous studies, we aimed to understand the influences of oblique angle of the substrate and scanning trajectory on the quality of the deposited films. First, we made several modifications to the APPJ system in order to accommodate tilted substrates. Then, we analyzed the difference between single and double-depositied processes in a given deposition time. Through the experimental data collected from the double-deposited process, we discovered that the tilted substrates would cause the distortion of the flow field and significantly affected the quality of the films. The analysis of the results from single-deposited process showed that if the trajectory was from the bottom to the top of the tilted substrates, the film quality would become worse due to the flow distortion effect mentioned before. Moreover, increasing the oblique angle or decreasing the scanning pitch would both deteriorate the quality severely. However, if the trajectory was in the opposite sequence, i.e. the scanning from bottom to top, the quality would be similar to that of the substrates without tilting, and the magnitude of the oblique angle and scanning pitch had minimum influences on the quality under this condition, which indicated that this particular trajectory could substantially reduce the flow distortion effect. Through various kinds of measurements, we concluded that flow distortion effect would increase the amount of large grain structure on the film and thus increased the surface roughness, number of crystal plane, decreased the packing density, increased the ratio of Ga-O bonding, increased material diffusion effect, these were the factors that lowered the quality of the film. The conclusion also provides important information for research related to film deposition on curved substrate.
Lastly, we set up a laser-assisted APPJ system to investigate the feasibility of directly creating GZO lines and patterns by using a laser to locally heat the substrate during spraying without the need of the heating plate and the subsequent lithography/etching process for patterning. We applied violet light and carbon dioxide (CO2) laser system to conduct some heating tests and assess the applicability of the proposed approach.

並列關鍵字

Atmospheric pressure plasma jet (APPJ) ； Gallium-doped zinc oxide (GZO) ； oblique angle effect ； trajectory effect ； curved substrate ； laser heating

參考文獻

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