摘要
氧化鎳薄膜具有適當的光學性質及導電性質，因此具有成為P型透明導電薄膜材料的潛力。藉由摻雜銅原子進入氧化鎳薄膜中，可能可以得到擁有較佳穿透率與導電率之氧化鎳薄膜。本研究是利用鎳金屬靶或不同寬度之銅箔與鎳金屬靶製作而成的複合靶材，進行反應性濺鍍，以得到氧化鎳薄膜與摻雜銅之氧化鎳薄膜。完成薄膜製備後再進行不同溫度( 200~500oC )之氧氣氛退火處理，更進一步改善薄膜的性質。
氧化鎳薄膜與摻雜銅之氧化鎳薄膜的材料特性、電性與光學性質將由以下儀器進行分析與研究。使用歐傑能譜分析儀進行薄膜成份縱深分析；使用拉塞福背向散射分析儀與電子微探儀進行薄膜成份分析；使用低掠角X光繞射進行薄膜結構與結晶性的分析；使用延伸X光吸收細微結構光譜術分析原子配位結構。導電性質則是使用霍爾量測搭配表面輪廓儀所量測之薄膜厚度，以得到薄膜載子濃度、載子遷移率以及電阻率，而電阻率也由四點探針量測所得。光學性質部份則是以紫外光-可見光光譜儀量測可見光範圍之光學穿透率，並且搭配五度角反 射器以量測薄膜反射率。
實驗結果顯示，氧化鎳薄膜與摻雜銅之氧化鎳薄膜皆呈現多晶狀態。以0.5公分寬或1.0公分寬銅箔之複合靶所製備的氧化鎳薄膜，薄膜中的銅元素含量分別為10at%與18at%。所有條件之初鍍膜，其氧原子/金屬原子比值皆大於一，經過退火處理之後，皆有變小的趨勢，推論為薄膜中氧原子以氧氣型態脫離。而摻雜銅之氧化鎳薄膜，經過退火處理之後，氧原子/金屬原子比值則減小至小於一。在薄膜的導電性質部分：氧化鎳薄膜之初鍍膜電阻率為0.19 ohm-cm；此值皆大於所有摻雜銅之氧化鎳薄膜的初鍍膜電阻率。而以1.0公分寬銅箔之複合靶所製備的摻雜銅之氧化鎳薄膜之電阻率0.02 ohm-cm為最低值。經過退火處理後的薄膜，電阻率皆明顯的增加。在薄膜的光學性質部分：氧化鎳薄膜之初鍍膜穿透率約為40%；然而摻雜銅之氧化鎳薄膜，初鍍膜穿透率約10~20%。經過退火之後，穿透率皆有提高，最高約為60%。由此可知，藉由摻雜銅原子進入氧化鎳薄膜中之方法，雖然能改善氧化鎳薄膜的導電率，但會有降低薄膜的穿透率。相對的退火處理則會改善薄膜穿透率但會降低導電率。

Abstract
Nickel oxide (NiO) is a potential candidate for fabricating p-type transparent conducting oxide thin films owing to its suitable optical and electrical properties. The transparency and conductivity of NiO films are possibly improved by doping copper atoms. In this study, NiO and copper-doped NiO (NiO:Cu) films were deposited by reactive sputtering from Ni and Ni+Cu composite targets, respectively. The sputtered films were subsequently annealed at different temperatures (200~500oC) in oxygen ambient to further modulate their properties.
The material, electrical and optical properties of NiO and NiO:Cu films were investigated as follows. Elemental depth profiles of NiO and NiO:Cu films was explored by using Auger electron spectroscopy (AES). Rutherford backscattering spectrometry (RBS) and electron probe X-ray microanalyzer (EPMA) were utilized to examine the composition. The crystal structure and crystallinity were identified by grazing incident angle x-ray diffraction (GIAXRD). The atomic coordination of NiO and NiO:Cu films was investigated by extended X-ray absorption fine structure spectrometry (EXAFS). Carrier concentration, mobility and resistivity were determined by Hall measurement. Film resistivity was also obtained by four-point probe. The transparency of NiO and NiO:Cu films was measured by ultraviolet-visible (UV-Vis) spectrophotometer and the reflectivity was measured with the 5o specular reflectance attachment of UV-Vis spectrophotometer.
The experimental results reveal that all NiO and NiO:Cu films exhibit polycrystalline structure. The content of copper in NiO films prepared by sputtering from composite targets with Cu foils of 0.5cm and 1.0cm in width are 10 at% and 18 at%, respectively. The oxygen/metal atomic ratios of as-deposited films are larger than one. After annealing, oxygen atoms may evaporate by in form of O2 gas and the oxygen/metal are decreased. Particularly, the oxygen/metal ratios of the NiO:Cu films decrease to less than one. About the electrical properties, resistivity of as-deposited NiO film is 0.19 ohm-cm, which is greater than the resistivity of all as-deposited NiO:Cu films. The NiO:Cu film prepared by sputtering from the composite target with Cu foil of 1.0 cm in width shows the lowest resistivity (0.02 ohm-cm). The resistivity increases significantly after annealing. Regarding the optical properties, the transparency of the as-deposited NiO film is about 40%, and the transparency of NiO:Cu films is about 10~20%. After annealing, the film transparency increases and the highest one is about 60%. In conclusion, doping copper into NiO films can improve the electrical conductivity, but lower the transparency. Annealing process, in contrast, enhances the film transparency but reduces the electrical conductivity.

1.B. G. Lewis, D. C. Paine, “Applications and processing of transparent conducting oxides”, MRS Bulletin, 25(8), 22 (2000).
2.楊明輝， “金屬氧化物透明導電材料的基本原理”， 工業材料，179期， 134 (2001).
3.J. L. Vossen, ”Transparent Conducting Films”, Physics of Thin Films, 9(1977), p1
4.溫志中，”ITO透明導電膜之濺鍍技術展望”，工業材料，166期(89)，p140.
5.P. Puspharajah, S. Radhakrishna, and A. K. Arof, “Transparent conducting lithium-doped nickel oxide thin films by spray pyrolysis technique”, Journal of Materials Science, 32, 3001 (1997).
6.C. F. Windisch, Jr., K. F. Ferris, G. J. Exarhos, “Synthesis and characterization of transparent conducting oxide cobalt-nickel spinel films”, Journal of Vacuum Science & Technology. A, 19, 1647 (2001).
7.陳璟鋒，P型氧化鎳薄膜之製備與其光性、電性及材料特性之研究，國立成功大學 材料科學及工程學系碩士論文，中華民國九十三年。
8.H. Kawazoe, H. Yanagi, K. Ueda, and H. Hosono, “Transparent p-type conducting oxide: design and fabrication of p-n heterojunctions”, MRS Bulletin, 25(8), 28 (2000).
9.李玉華，“透明導電膜及其應用”，科儀新知，12卷第一期，94~102 (1980)
10.D. S. Ginley, C. Bright, “Transparent conducting oxides”, MRS Bulletin, 25(8), 15 (2000).
11.R. G. Gordon, “Criteria for choosing transparent conductors”, MRS Bulletin, 25(8), 52 (2000).
12.H. Kawazoe, K. Ueda, “Transparent conducting oxides based on the spinel structure”, Journal of the American Ceramic Society, 82, 3330 (1999).
13.H. Kawazoe, M. Yasukawa, H. Hyodo, M. Kurita, “P-type electrical conduction in transparent thin films of CuAlO2”, Nature, 389, 939 (1997).
14.H. Yanagi, S. Inoue, K. Ueda, H. Kawazoe, H. Hosono, “Electronic structure and optoelectronic properties of transparent p-type conducting CuAlO2”, Journal of Applied Physics, 88(7), 4159 (2000).
15.K. Ueda, T. Hase, H. Yanagi, H. Kawazoe, and H. Hosono, “Epitaxial growth of transparent p-type conducting CuGaO2 thin films on sapphire .001. substrates by pulsed laser deposition”, Journal of Applied Physics, 89(3), 1970 (2001).
16.顧鴻壽， “光電平面面板顯示器基本概論”， 高立圖書有限公司， (2002)
17.N. Ohshima, M. Nakada, Y. Tsukamoto, “Structural and magnetic properties of Ni-O/Ni-Fe bilayer films”, Japanese Journal of Applied Physics, 35, L1585 (1996).
18.O. Kohmoto, H. Nakagawa, F. Ono, A. Chayahara, “Ni-defective value and resistivity of sputtered NiO films”, Journal of Magnetism and Magnetic Materials, 226-230,1627 (2001).
19.Y.-M. Chiang, D. P. Birnie III, W. D. Kingery, “Physical ceramics”, John Wiley & Sons, p.24, p.105, p.129, p.131 (1997).
20.B. D. Cullity, S. R. Stock, “Elements of X-ray diffraction”, 3rd edition, Prentice Hall, p.48 (2001).
21.I. Hotový, D. Búc, “Characterization of NiO thin films deposited by reactive sputtering”, Vacuum, 50, 41 (1998).
22.O. Kohmoto, H. Nakagawa, Y. Isagawa, A. Chayahara, “Effect of heat treatment on the oxygen content and resistivity in sputtered NiO films”, Journal of Magnetism and Magnetic Materials, 226-230, 1629 (2001).
23.D. Adler, J. Feinleib., “Electrical and optical properties of narrow-band materials”, Physical Review B, 2, 3112 (1970).
24.G. P. Sykora, T. O. Mason, “Defect studies above 1 atm oxygen: NiO and CoO”, American Ceramic Society : nonstoichiometric compounds, 23, 45 (1987).
25.B. Sasi, K. G. Gopchandran, P. K. Manoj, P. Koshy, “Preparation of transparent and semiconducting NiO films”, Vacuum, 68, 149 (2003).
26.W. Estrada, A. M. Andersson, C. G. Granqvist, “Electrochromic nickel-oxide-based coatings made by reactive DC magnetron sputtering: Preparation and optical properties”, Journal of Applied Physics, 64, 3678 (1988).
27.I. C. Faria, M. Kleinke, A. Gorenstein, “Toward efficient electrochromic NiOx films: A study of microstructure, morphology, and stoichiometry of radio frequency sputtered films”, Journal of the Electrochemical Society, 145, 235 (1998).
28.K. Yoshimura, T. Miki, S. Tanemura, “Nickel oxide electrochromic thin films prepared by reactive dc magnetron sputtering”, Japanese Journal of Applied Physics, 34, 2440 (1995).
29.I. Hotovy, J. Huran, P. Siciliano, S. Capone, “The influences of preparation parameters on NiO thin film properties for gas-sensing application”, Sensors and Actuators. B, 78, 126 (2001).
30.J. Olivier, B. Servet, M. Vergnolle, M. Mosca, “Stability/instability of conductivity and work function changes of ITO thin films, UV-irradiated in air or vacuum”, Synthetic Metals, 122, 87 (2001).
31.I-M. Chan, F. C. Hong, “Improve performance of the single-layer and double-layer organic light emitting diodes by nickel oxide coated indium tin oxide anode”, Thin Solid Films, 450, 304 (2004).
32.R. H. Horng, D. S. Wuu, Y. C. Lien, W. H. Lan, “Low-resistance and high-transparency Ni/indium tin oxide ohmic contacts to p-type GaN”, Applied Physics Letters, 79, 2925 (2001).
33.楊謹隆，金與氧化鎳薄膜應用於p-型氮化鎵歐姆接觸材料之研究，國立成功大學 材料科學及工程學系博士論文，中華民國九十四年。
34.M. J. Carey, A. E. Berkowitz, “CoO-NiO superlattices: Interlayer interactions and exchange anisotropy with Ni81Fe19”, Journal of Applied Physics, 73, 6892 (1993).
35.E. Fujii, A. Tomozawa, H. Torii, R. Takayama, “Preferred orientations of NiO films prepared by the plasma-enchanced metalorganic chemical vapor deposition”, Japanese Journal of Applied Physics, 35, L328 (1996).
36.S. S. Lee, D. G. Hwang, C. M. Park, J. R. Rhee, “Effects of crystal texture on exchange anisotropy in NiO spin valves”, Journal of Applied Physics, 81, 5298 (1997).
37.O. Kohmoto, H. Nakagawa, Y. Isagawa, A. Chayahara, “Effect of heat treatment on the oxygen content and resistivity in sputtered NiO films”, Journal of Magnetism and Magnetic Materials, 226-230, 1629 (2001).
38.Y. M. Lu, W. S. Hwang, J. S. Yang, H. C. Chuang, “Properties of nickel oxide thin films deposited by RF reactive magnetron sputtering”, Thin Solid Films, 420-421, 54 (2002).
39.Y. M. Lu, W. S. Hwang, J. S. Yang, “Effects of substrate temperature on the resistivity of non-stoichiometric sputtered NiOx films”, Surface and Coatings Technology, 155, 231 (2002).
40.H. Sato, T. Minami, S. Takata, T. Yamada, “Transparent conducting p-type NiO thin films prepared by magnetron sputtering”, Thin Solid Films, 236, 27 (1993).
41.C. F. Windisch, Jr., G. J. Exarhos, K. F. Ferris, M. H. Engelhard, “Infrared transparent spinel films with p-type conductivity”, Thin Solid Films, 398-399, 45 (2001).
42.A. Agrawal, H. R. Habibi, R. K. Agrawal, J. P. Cronin, “Effect of deposition pressure on the microstructure and electrochromic properties of electron-beam-evaporated nickel oxide films”, Thin Solid Films, 221, 239 (1992).
43.M. Kitao, K, Izawa, K. Urabe, T. Komatsu, S. Kuwano, S. Yamada, “Preparation and electrochromic properties of rf-sputtered NiOx films prepared in Ar/O2/H2 atmosphere ”, Japanese Journal of Applied Physics, 33, 6656 (1994).
44.E. Fujii, A. Tomozawa, S. Fujii, H. Torii, “NaCl-type oxide films prepared by plasma-enhanced metalorganic chemical vapor deposition”, Japanese Journal of Applied Physics, 32, L1448 (1993).
45.J. K. Kang, S. W. Rhee, “Chemical vapor deposition of nickel oxide films from Ni(C2H5)2/O2”, Thin Solid Films, 391, 57 (2001).
46.A. J. Varkey, A. F. Fort, “Solution growth technique for deposition of nickel oxide films”, Thin Solid Films, 235, 47 (1993).
47.M. Tanaka, M. Mukai, Y. Fujimori, M. Kondoh, “Transition metal oxide films prepared by pulsed laser deposition for atomic beam detection”, Thin Solid Films, 281-282, 453 (1996).
48.J. Pelleg, L. Z. Zevin, S. Lungo, “Reactive-sputter-deposited TiN films on glass substrates”, Thin Solid Films, 197, 117 (1991).
49.D. A. Neamen, “Semiconductor physics & devices”, 2nd ed., Irwin, McGraw-Hill, (1997).
50.M. Fox, “Optical properties of solids”, Oxford, New York, (2001).
51.L. F. Mattheiss, “Electromic structure of the 3d transition-metal monoxides. I. Energy-band results”, Physical Review B, 5, 290 (1972).