以射頻磁控共濺鍍法成長氧化鋅摻雜氟化鋁透明導電膜之光電性質研究

Opto-electronic properties of ZnO doped with AlF3 transparent conductive films by RF co-sputtering technique

劉晉宏(Chin-Hung Liu)

指導教授 ： 林天財

共同指導教授 ： 張慎周(Shang-Chou Chang)

崑山科技大學/工程學院/電機工程研究所/碩士(2008年)

https://doi.org/10.6828/KSU.2008.00020

摘要

隨著光電產業的發展，不斷有新材料被發展出來，透明導電膜是近年來LCD 產業的熱門材料，而所謂透明導電膜是一種吸收紫外光、讓可見光穿透與反射紅外線的材料。由於氧化鋅薄膜具有顯著的C軸優選成長取向及在可見光區有高透光率，但其未摻雜的氧化鋅薄膜電阻值偏高(約為1~100Ω-cm)，其導電特性主要受限於非化學計量比的氧空缺及鋅間隙原子所影響，因此提高氧化鋅薄膜的導電率為目前研究之重點。
本研究為了提升氧化鋅薄膜之導電率，採用RF射頻磁控共濺鍍法進行氧化鋅及氟化鋁雙靶共濺鍍，藉以製備氧化鋅摻雜氟化鋁薄膜。利用Al+3取代Zn+2、F-1取代O-2，來增加其載子濃度，進而提升導電率。實驗中改變不同射頻濺鍍功率、沈積時間、製程壓力、基板溫度以求得最佳光電特性之參數匹配。薄膜製備完成後，進行真空熱處理退火製程，期望能更進一步改善薄膜的導電性及透光性。結果得知ZnO：AlF3薄膜結構與ZnO相同，皆呈[002]優選方向，在改變氟化鋁濺鍍功率時，XRD繞射波峰會隨著氟化鋁濺鍍功率的增加而上升，由EDS元素分析明顯的看出鋁及氟的原子含量上升。當ZnO：AlF3濺鍍功率為100W：75W時可得到最低的電阻率3.60×10-2Ω-cm ，最高載子濃度4.06×1020 cm-3且載子遷移率為0.62 cm2/Vs，在可見光區平均穿透率為85%，確實改善了ZnO薄膜的導電性質。藉由氟化鋁濺鍍功率的提升，相對的提高氧化鋅薄膜中的載子濃度，因此光學能隙有寬化的現象產生，當氟化鋁濺鍍功率從25W增加至125W時，光學能隙值由
3.33eV提升至3.74eV。

關鍵字

氧化鋅 ； 濺鍍 ； 透明導電膜

並列摘要

Many new materials were developed continuously for opto-elecric industry in current. Transparent conducting films which have a high transmittance in visible light region and low resistivity is a attractive material in LCD industry as a elecrode. In general , transparent conductive films have high absorption in UV , high transmittance in visible light and high reflection in IR. Zinc oxide (ZnO) films have a strong C-axis preferred orientation and high transmittance in visible light range. The conduction of undoped ZnO films have a high resistivity of 1~100Ω-cm. The conductive mechanism of ZnO are dominated by electron due to the oxygen vacancies and Zn interstitial atoms to create electron carriers.Therefore , to increase the conduction of ZnO films are one of major points in this study.
In order to increasing the conductivity RF magnetron co-sputtering technique was used to deposit AlF3 doped ZnO films in argon atmosphere. The main mechanism of ZnO doped with AlF3 film are to use aluminum substitutional zinc and fluorine substitutional oxygen , hence the resistivity decrease as well as increasing carrier concentration. In this experiment ,we changed target powers , deposition time , working pressure and substrate temperature to observe different optoelectric properties of films. After film deposited , the vacuum annealing were used to enhance the improvement of the opto-electric properties of films. The results showed that both of ZnO and ZnO:AlF3 films exhibt a same structures and have [002] preferred orientation by XRD identified. The [002] peak shifts to high angle when the AlF3 target power increases , that is ascribed to the aluminum substituting zinc and fluorine substituting oxygen. When AlF3 target power increases , the contents of aluminum and fluorine increases at EDS analysis. The lowest resistivity of 3.60×10-2 Ω-cm can be obtained at the AlF3 target power of 75W and ZnO power of 100W. In this condition , the carrier concentration is 4.06×1020 cm-3 , the mobility is 0.62 cm2/Vs and the transmittance is 85% in visible light region. The optical band gap are broaden at AlF3 target powers increasing from 25W to125W in respective to the optical band gap increasing from 3.33eV to 3.74eV.

並列關鍵字

ZnO ； sputter ； TCO

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