共濺鍍氧化銦鋅透明導電薄膜熱穩定性之研究

Thermal stability of Zn-doped ITO films prepared by rf magnetron cosputtering system

林俊興(Chun-Hsing Lin)

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2006年)

摘要

本研究利用射頻磁控共濺鍍系統，同時濺鍍氧化銦錫及氧化鋅靶材，在室溫環境下製備具有不同鋅原子比例(Zn / (Zn+In) at.%)之氧化銦鋅透明導電薄膜，分別在還原氣體（95 % Ar + 5 % H2）、氧氣及大氣環境下進行熱處理製程，觀察薄膜結晶性及電特性變化。研究結果顯示經由熱處理的氧化銦鋅薄膜，電特性與薄膜中鋅原子含量息息相關，在還原氣體環境下熱處理溫度達到700℃時，含量較低之氧化銦鋅薄膜，其電阻率有明顯上升的趨勢。根據x光繞射圖譜量測結果顯示，造成薄膜導電率急遽下降的原因係由於熱處理過程中，氧化銦鋅薄膜中形成過多的氧缺位而產生金屬銦的結晶相，進而劣化了透明導電薄膜的導電性以及可見光穿透率。而在氧氣及空氣環境下熱處理的氧化銦鋅薄膜，電阻率隨著熱處理溫度的升高而上升，這是由於鋅原子具有較低的氧化位能，使得鋅原子會捕捉熱處理環境中的氧原子，所以在具有氧氣成分環境進行熱處理，鋅原子會補捉製程中的氧原子，而抑制氧缺位的形成，使得薄膜電阻率上升，由載子濃度的量測結果亦顯示，經由氧氣及大氣下熱處理的氧化銦鋅薄膜，濃度皆有下降的趨勢。

並列摘要

Indium zinc oxide (IZO) thin films at various atomic ratios [Zn / (Zn + In) at.%] were prepared by rf cosputtering system at room temperature using indium tin oxide (ITO) and zinc oxide (ZnO) targets. The thermal stability of ITO and cosputtered films annealed under reducing atmosphere (forming gas 95% Ar + 5% H2) oxygen, and atmosphere ambient were investigated. The film resistivity of ITO and IZO films at lower atomic ratios was drastically increased at an annealing temperature of 700℃. The appearance of the metal-like In phase was responsible for the significantly increase in the film resistivity. In contrast, the film resistivity of IZO films at higher atomic ratios was stable at elevated annealing temperatures. The related thermal stability was attributed to the crystallization of ZnkIn2O3+k compounds and sequentially suppressed the formation of the metal-like In phase. The thermal degradation mechanism of IZO films annealed under oxygen and atmosphere ambient was concluded to be the oxygen atoms attracted by zinc atoms due to their higher oxidation potential.

參考文獻

【36】 吳俊慶, “以射頻共濺鍍系統於室溫下沉積透明導電膜之研究”, 國立虎尾科技大學碩士論文, pp. 25-26 (2005)

【2】 K. H. Choi, J. Y. Kim, Y. S. Lee, and H. J.Kim, “ITO/Ag/ITO multilayer films for the application of a very low resistance transparent electrode” Thin Solid Films, 341, pp. 152-155 (1999).

【3】 H. Ma, J. S. Cho, and C. H. Park, “Effects and microstructures of indium tin oxide seed layers for perpendicular magnetic recording media” Surf. Coat. Technol., 153, pp. 131-136 (2002).

【4】 Y. S. Jung, D. W. Lee, and D. Y. Jeon, “Influence of dc magnetron sputtering parameters on surface morphology of indium tin oxide thin films” Appl. Surf. Sci., 221 pp. 136-142 (2004).

【5】 W. J. Lee, Y. K. Fang, J. J. Ho, C. Y. Chen, L H. Chiou S. J. Wang, F. Dai, T. Hsieh, R. Y. Tsai, D. Huang, and F. C. Ho, “Organic light-emitting diode on indium zinc oxide film prepared by ion assisted deposition dc sputtering system” Solid-State Electron., 46 pp. 477-480 (2002).