雷射輔助噴射式大氣電漿系統開發與應用於鍍製透明導電薄膜與圖樣

Development of Laser-Assisted Atmospheric Pressure Plasma Jet System and Its Application in Fabricating Highly Transparent Conductive Films and Patterns

陳俞蓁(Yu-Chen 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(2020年)

https://doi.org/10.6342/NTU202001784

摘要

目前透明導電薄膜以銦錫氧化物(Indium tin oxide, ITO)為主流，但銦為稀有金屬，其價格日益攀升，鎵摻雜氧化鋅(Gallium doped zinc oxide, GZO)因為具備寬能隙(> 3 eV)、高導電性等特性，為適合的替代材料之一。本研究使用噴射式大氣電漿(Atmospheric pressure plasma jet, APPJ)鍍製GZO薄膜，此法的優點是不需要使用真空腔室與能用於大面積薄膜沉積。
本研究深入探討雷射退火對以大氣電漿法沉積的GZO薄膜之影響，雷射源選用二氧化碳雷射(波長為10600 nm)，二氧化碳雷射很適合用於加熱沉積在玻璃上的薄膜，因為其對玻璃有相當小的光學穿透深度(~1.66 μm)。透過選擇適當雷射功率，除了能提升薄膜的導電性，亦能提升薄膜整體的均勻度。由於薄膜鍍製過程中受到非刻意大氣退火，剛沉積完成的薄膜上某些區域堆積在晶粒邊界的鎵氧團簇含量較多，這些鎵氧團簇會影響自由載子的移動，從而降低霍爾遷移率，所以薄膜的導電性呈現區域性落差。經由雷射退火可以消除晶粒邊界的鎵氧團簇，因此薄膜的導電度、均勻度皆獲得改善，除此之外，退火後薄膜光學性質亦有微幅提升。
在諸多應用中，透明導電薄膜最常被當作透明電極使用，有別於主流、繁複的透明電極製作法─ 先沉積一層薄膜後續再經過光微影蝕刻技術以製成，本研究透過二氧化碳雷射結合噴射式大氣電漿系統，設計並建構出一套系統得以一步驟性的做出線寬為350 μm的GZO透明導電圖樣，完成諸多展示並對圖樣的光電性質進行分析。

關鍵字

大氣電漿 ； 透明導電薄膜 ； 氧化鋅摻雜鎵 ； 雷射退火 ； 透明電極 ； 透明導電圖樣

並列摘要

Transparent conductive film is mainly made of Indium tin oxide (ITO). However, indium is a rare metal with rising price. Therefore, many researchers intend to find substitute materials and gallium-doped zinc oxide (GZO) turns out to be one of appropriate alternatives with wide band gap (> 3 eV) and high conductivity. In this research, we apply atmospheric pressure plasma jet (APPJ) to deposit GZO thin film. APPJ is a cost-effective way to deposit thin film since it does not require a vacuum chamber. Another strength of APPJ is that it is applicable for deposition of film on large area.
One part of the study is digging into CO2 laser (wavelength = 10600 nm) annealing effect on GZO film deposited with APPJ. The CO2 laser possesses low optical depth (~1.66 μm) for glass, and is thus suitable for thermally annealing the film deposited on glass substrates. It is discovered that not only is the film’s conductivity enhanced but film’s uniformity is also improved after laser annealing of appropriate power. The main reason is the elimination of Ga-O clusters. Due to unintentional thermal annealing in atmosphere during manufacture, some regions of as-deposited film contain more Ga-O clusters, such as GaOx and Ga2O3, at grain boundaries than others. These clusters serve as electron traps and degrade the mobility of free carriers in films. As a result, the conductivity of the as-deposited film differs from region to region. After laser annealing, the amount Ga-O clusters decreases considerably at the regions which initially possess higher amount of Ga-O clusters and the film’s crystallinity is enhanced a little bit. Therefore, the conductivity and uniformity of film is both improved. In addition, the optical properties of film are also slightly elevated.
The other part of the study is about fabricating transparent conductive patterns with a novel method CO2 laser assisted atmospheric pressure plasma jet. Traditionally, fabrication of transparent conductive patterns contains a series of procedures which include film deposition, photolithography and etching. In the method of CO2 laser-assisted atmospheric pressure plasma jet, the lengthy processes for making transparent conductive patterns are concentrated into one step and no vacuum chamber is required. In this study, we design and construct a laser assisted APPJ system, and then demonstrate several transparent conductive patterns and analyze their optoelectronic properties.

並列關鍵字

Atmospheric pressure plasma jet ； Transparent conductive oxide ； Gallium doped zinc oxide ； Laser annealing ； Laser-assisted manufacture ； Transparent conductive electrode ； Patterning

參考文獻

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