Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-24T13:52:32.602Z Has data issue: false hasContentIssue false
  • English
  • Français

Reactive magnetron sputtering of transparent conductive oxide thin films: Role of energetic particle (ion) bombardment

Published online by Cambridge University Press:  08 February 2012

Klaus Ellmer  and
Thomas Welzel
Klaus Ellmer*
Affiliation:
Helmholtz-Zentrum für Materialien und Energie GmbH, 14109 Berlin, Germany
Thomas Welzel
Affiliation:
Helmholtz-Zentrum für Materialien und Energie GmbH, 14109 Berlin, Germany
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Transparent conductive oxides (TCOs) are degenerately doped compound semiconductors with wide band gaps (Eg > 3 eV), which are used as transparent electrodes in optoelectronic devices. Reports on the influence of negative ions on the electrical properties of TCO films are reviewed and compared with our results. It was reported that the radial resistivity distributions depend (i) on the excitation mode of the magnetron (direct current or radio frequency), (ii) on the erosion state of the sputtering target, and (iii) on the density of the ceramic targets. This can be explained by the fact that the negative ions in magnetron discharges (in our case O−) are generated at the target surface and accelerated toward the growing films. Their energy and their radial distribution depend on the discharge voltage and the shape of the emitting surface, i.e., of the erosion groove. Ways for reducing the effect of negative ion bombardment are discussed.

Keywords

Plasma depositionTransparent conductorElectrical properties
Type
Reviews
Information
Journal of Materials Research , Volume 27 , Issue 5: Focus Issue: Plasma and Ion-Beam Assisted Materials Processing , 14 March 2012 , pp. 765 - 779
Copyright
Copyright © Materials Research Society 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Ellmer, K., Klein, A., and Rech, B. (Eds.): Transparent Conductive Zinc Oxide: Basics and Applications in Thin Film Solar Cells (Springer, Berlin, 2008).CrossRefGoogle Scholar
2.Helwig, G. : Elektrische Leitfähigkeit und Struktur aufgestäubter Kadmiumoxydschichten. Z. Phys. 132, 621 (1952).CrossRefGoogle Scholar
3.Rupprecht, G. : Untersuchungen der elektrischen und lichtelektrischen Leitfähigkeit dünner Indiumoxydschichten. Z. Phys. 139, 504 (1954).CrossRefGoogle Scholar
4.Ginley, D.S., Hosono, H., and Paine, D.C. (Eds.): Handbook of Transparent Conductors (Springer, New York, 2010).Google Scholar
5.Ellmer, K. : Electrical properties, in Transparent Conductive Zinc Oxide: Basics and Application in Thin Film Solar Cells, edited by Ellmer, K., Klein, A., Rech, B. (Springer, Berlin, 2008), p. 35.CrossRefGoogle Scholar
6.Nath, P., Bunshah, R.F., Basol, B.M., and Staffsud, O.M. : Electrical and optical properties of In2O3:Sn films prepared by activated reactive evaporation. Thin Solid Films 72, 463 (1980).CrossRefGoogle Scholar
7.Randhawa, H.S., Matthews, M.D., and Bunshah, R.F. : SnO2 films prepared by activated reactive evaporation. Thin Solid Films 83, 267 (1981).CrossRefGoogle Scholar
8.Hamberg, I. and Granqvist, C.G. : Evaporated Sn-doped In2O3 films: Basic optical properties and applications to energy-efficient windows. J. Appl. Phys. 60(11), R123 (1986).CrossRefGoogle Scholar
9.Hu, J. and Gordon, R.G. : Textured aluminium-doped zinc oxide thin films from atmospheric pressure chemical-vapor deposition. J. Appl. Phys. 71(2), 880 (1992).CrossRefGoogle Scholar
10.Fay, S. and Shah, A. : Zinc Oxide Growth by CVD Process as Transparent Contact for Thin Film Solar Cell Applications. Transparent Conductive Zinc Oxide: Basics and Application in Thin Film Solar Cells, edited by Ellmer, K., Klein, A., Rech, B. (Springer, Berlin, 2007), p. 235.Google Scholar
11.Rozgonyi, G.A. and Polito, W.J. : Preparation of ZnO thin films by sputtering of the compound in oxygen and argon. Appl. Phys. Lett. 8, 220 (1966).CrossRefGoogle Scholar
12.Hata, T., Minamikawa, T., Noda, E., Moromoto, O., and Hada, T. : High rate deposition of ZnO films using improved DC reactive magnetron sputtering technique. Jpn. J. Appl. Phys. Suppl. 18-1, 219 (1978).Google Scholar
13.Tominaga, K., Ueshiba, N., Shintani, Y., and Tada, O. : High-energy neutral atoms in the sputtering of ZnO. Jpn. J. Appl. Phys. 20(3), 519 (1981).CrossRefGoogle Scholar
14.Hirata, G.A., McKittrick, J., Siqueiros, J., Lopez, O.A., Cheeks, T., Contreras, O., and Yi, J.Y. : High-transmittance-low resistivity ZnO:Ga films by laser ablation. J. Vac. Sci. Technol. A 14(3), 791 (1996).CrossRefGoogle Scholar
15.Kaidashev, E.M., Lorenz, M., von Wenckstern, H., Rahm, A., Semmelhack, H-C., Han, K-H., Benndorf, G., Bundesmann, C., Hochmuth, H., and Grundmann, M. : High electron mobility of epitaxial ZnO thin films on c-plane sapphire grown by multistep pulsed-laser deposition. Appl. Phys. Lett. 82(22), 3901 (2003).CrossRefGoogle Scholar
16.Goldsmith, S. : Filtered vacuum arc deposition of undoped and doped ZnO thin films: Electrical, optical, and structural properties. Surf. Coat. Technol. 201, 3993 (2006).CrossRefGoogle Scholar
17.Tay, B.K., Zhao, Z.W., and Chua, D.H.C. : Review of metal oxide films deposited by filtered cathodic vacuum arc technique. Mater. Sci. Eng., R 52, 1 (2006).CrossRefGoogle Scholar
18.Miyata, T., Honma, Y., and Minami, T. : Preparation of transparent conducting B-doped ZnO films by vacuum arc plasma evaporation. J. Vac. Sci. Technol. A 25(4), 1193 (2007).CrossRefGoogle Scholar
19.Anders, A., Lim, S.H.N., Yu, K.M., Andersson, J., Roseìn, J., McFarland, M., and Brown, J. : High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition. Thin Solid Films 518, 3313 (2010).CrossRefGoogle Scholar
20.Mendelsberg, R.J., Lim, S.H.N., Zhu, Y.K., Wallig, J., Milliron, D.J., and Anders, A. : Achieving high mobility ZnO: Al at very high growth rates by dc filtered cathodic arc deposition. J. Phys. D 44, 232003 (2011).CrossRefGoogle Scholar
21.Nonomura, K., Loewenstein, T., Michaelis, E., Wöhrle, D., Yoshida, T., Minoura, H., and Schlettwein, D. : Photoelectrochemical characterisation and optimisation of electrodeposited ZnO thin films sensitised by porphyrins and phthalocyanines. Phys. Chem. Chem. Phys. 7, 3867 (2006).CrossRefGoogle Scholar
22.Thornton, J.A. : High Rate Thick Film Growth. Annual Review of Material Science, Vol. 7, edited by Huggins, R.A., Bube, R.H., and Roberts, R.W. (Annual Reviews Inc., Palo Alto, CA, 1977), p. 239.Google Scholar
23.McKenzie, D.R., Marks, N.A., Guan, P., Pailthorpe, B.A., McFall, W.D., and Yin, Y. : Energetic condensation as a means of inducing the growth of films containing high pressure phases, in Surface Science: Principles and Current Applications, edited by MacDonald, R.J., Taglauer, E.C., and Wandelt, K.R. (Springer, Berlin, 1996), p. 251.Google Scholar
24.Cuomo, J.J., Gambino, R.J., Harper, J.M.E., and Kuptsis, J.D. : Origin and effects of negative ions in the sputtering of intermetallic compounds. IBM J. Res. Dev. 21, 580 (1977).CrossRefGoogle Scholar
25.Winters, H.F. : Elementary processes at solid surfaces immersed in low pressure plasmas, in Plasma Chemistry III, Vol. 94, edited by Veprek, S. and Venugopalan, M. (Springer, Berlin, 1980), p. 69.CrossRefGoogle Scholar
26.Brice, D.K., Tsao, J.Y., and Picraux, S.T. : Partitioning of ion-induced surface and bulk displacements. Nucl. Instrum. Methods Phys. Res. B 44, 68 (1989).CrossRefGoogle Scholar
27.Penning, F.M. : USA Patent 2,146, 0251(939).CrossRefGoogle Scholar
28.Penning, F.M. : Ein neues Manometer für niedrige Gasdrucke, insbesondere zwischen 10−3 und 10−5 mm. Physica 4(2), 71 (1937).CrossRefGoogle Scholar
29.Clarke, P.J. : USA Patent 3,711,398 (1973).Google Scholar
30.Chapin, J.S. : The planar magnetron. Res. Dev. 25(1), 37 (1974).Google Scholar
31.Wright, M. and Beardow, T. : Design advances and applications of the rotatable cylindrical magnetron. J. Vac. Sci. Technol. A 4, 388 (1986).CrossRefGoogle Scholar
32.Nadel, S.J., Greene, P., Rietzel, J., Perata, M., Malaszewski, L., and Hill, R. : Advanced generation of rotatable magnetron technology for high performance reactive sputtering. Thin Solid Films 502, 15 (2006).CrossRefGoogle Scholar
33.Richter, F., Welzel, T., Kleinhempel, R., Dunger, T., Knoth, T., Dimer, M., and Milde, F. : Ion-energy distributions in AZO magnetron sputtering from planar and rotatable magnetrons. Surf. Coat. Technol. 204, 845 (2009).CrossRefGoogle Scholar
34.Ellmer, K. : Magnetron Discharges for Thin Film Deposition. Low Temperature Plasmas. Fundamentals, Technologies and Techniques, Vol. 2, edited by Hippler, R., Kersten, H., Schmidt, M., and Schoenbach, K.H. (Wiley-VCH, Berlin, 2008), p. 101.Google Scholar
35.Thompson, M.W. : II. The energy spectrum of ejected atoms during the high energy sputtering of gold. Philos. Mag. 18/152, 377 (1968).CrossRefGoogle Scholar
36.Eckstein, W. : Computer Simulation of Ion-Solid Interactions (Springer, Berlin, 1991).CrossRefGoogle Scholar
37.Yamamura, Y. and Tawara, H. : Energy dependence of ion-induced sputtering yields from monatomic solids at normal incidence. At. Data Nucl. Data Tables 62(2), 149 (1996).CrossRefGoogle Scholar
38.Lieberman, M.A. and Lichtenberg, A.J. : Principles of Plasma Discharges and Material Processing (Wiley, New York, 1994).Google Scholar
39.Harper, J.M.E., Cuomo, J.J., Gambino, R.J., Kaufman, H.R., and Robinson, R.S. : Mean free path of negative ions in diode sputtering. J. Vac. Sci. Technol. 15(4), 1597 (1978).CrossRefGoogle Scholar
40.Davis, W.D. and Vanderslice, T.A. : Ion energies at the cathode of a glow discharge. Phys. Rev. 131(1), 219 (1963).CrossRefGoogle Scholar
41.Zeuner, M., Neumann, H., Zalman, J., and Biederman, H. : Sputter process diagnostics by negative ions. J. Appl. Phys. 83(10), 5083 (1998).CrossRefGoogle Scholar
42.Mráz, S. and Schneider, J.M. : Influence of the negative oxygen ions on the structure evolution of transition metal oxide thin films. J. Appl. Phys. 100, 023503 (2006).CrossRefGoogle Scholar
43.Mahieu, S. and Depla, D. : Correlation between electron and negative O- ion emission during reactive sputtering of oxides. Appl. Phys. Lett. 90, 121117 (2007).CrossRefGoogle Scholar
44.Wendt, R. and Ellmer, K. : Desorption of Zn from a growing ZnO:Al-film deposited by magnetron sputtering. Surf. Coat. Technol. 93(1), 27 (1997).CrossRefGoogle Scholar
45.Wendt, R., Ellmer, K., and Wiesemann, K. : Thermal power at a substrate during ZnO:Al thin film deposition in a planar magnetron sputtering system. J. Appl. Phys. 82(5), 2115 (1997).CrossRefGoogle Scholar
46.Welzel, T., Kleinhempel, R., Dunger, T., and Richter, F. : Ion energy distributions in magnetron sputtering of zinc aluminium oxide. Plasma Processes Polym. 6(S1), S331 (2009).CrossRefGoogle Scholar
47.Seeger, S., Harbauer, K., and Ellmer, K. : Ion-energy distributions at a substrate in reactive magnetron sputtering discharges in Ar/H2S from copper, indium and tungsten targets. J. Appl. Phys. 105, 053305 (2009).CrossRefGoogle Scholar
48.Shintani, Y., Nakanishi, K., Takawaki, T., and Tada, O. : Behaviours of high-energy electrons and neutral atoms in the sputtering of BaTiO3. Jpn. J. Appl. Phys. 14, 1875 (1975).CrossRefGoogle Scholar
49.Kester, D.J. and Messier, R. : Predicting negative ion resputtering in thin films. J. Vac. Sci. Technol. A 4(3), 496 (1986).CrossRefGoogle Scholar
50.Hanak, J.J. and Pellicane, J.P. : Effect of secondary electrons and negative ions on sputtering of films. J. Vac. Sci. Technol. 13(1), 406 (1976).CrossRefGoogle Scholar
51.Cuomo, J.J., Gambino, R.J., Harper, J.M.E., Kuptsis, J.D., and Webber, J.C. : Significance of negative ion formation in sputtering and SIMS analysis. J. Vac. Sci. Technol. 15(2), 281 (1978).CrossRefGoogle Scholar
52.Ngaruiya, J.M., Kappertz, O., Mohamed, S.H., and Wuttig, M. : Structure formation upon reactive direct current magnetron sputtering of transition metal oxide films. Appl. Phys. Lett. 85(5), 748 (2004).CrossRefGoogle Scholar
53.Keller, J.H. and Simmons, R.G. : Sputtering process model of deposition rate. IBM J. Res. Dev. 23(1), 24 (1979).CrossRefGoogle Scholar
54.Ellmer, K. and Mientus, R. : in Proceedings of the Fourth International Symposium on Trends and New Applications in Thin Films/11th Conference on High Vacuum, Interfaces and Thin Films, edited by Hecht, G., Richter, F., and Jahn, J. (DGM Informationsgesellschaft mbH, Oberursel, Dresden, March, 1994), p. 131.Google Scholar
55.Baragiola, R.A. : Electron Emission from Slow Ion-Solid Interactions. Low Energy Ion-Surface Interactions, edited by Rabalais, J.W. (Wiley, Chichester, 1994), p. 187.Google Scholar
56.Barnett, S.A., Bajor, G., and Greene, J.E. : Growth of high‐quality epitaxial GaAs films by sputter deposition. Appl. Phys. Lett. 37, 734 (1980).CrossRefGoogle Scholar
57.Rabalais, J.W., Al-Bayati, A.H., Boyd, K.J., Marton, D., Kulik, J., Zhang, Z., and Chu, W.K. : Ion-energy effects in silicon ion-beam epitaxy. Phys. Rev. B 53(16), 10781 (1996).CrossRefGoogle ScholarPubMed
58.Greene, J.E., Barnett, S.A., Sundgren, J-E., and Rockett, A. : Low-Energy Ion/Surface Interactions During Film Growth from the Vapor Phase. Ion Beam Assisted Film Growth, edited by Itoh, T. (Elsevier, Amsterdam, 1989), p. 101.CrossRefGoogle Scholar
59.Itoh, T. (Ed.): Ion Beam Assisted Film Growth (Elsevier, Amsterdam, 1989).Google Scholar
60.Petrov, I., Barna, P.B., Hultman, L., and Greene, J.E. : Microstructural evolution during film growth. J. Vac. Sci. Technol. A 21(5), S117 (2003).CrossRefGoogle Scholar
61.Marton, D. : Film Deposition from Low-Energy Ion Beams. Low Energy Ion-Surface Interactions, edited by Rabalais, J.W. (Wiley, Chichester, 1994), p. 481.Google Scholar
62.Anders, A. : A structure zone diagram including plasma-based deposition and ion etching. Thin Solid Films 518, 4087 (2010).CrossRefGoogle Scholar
63.Wendler, E., Bilani, O., Gärtner, K.Wesch, W., Hayes, M., Auret, F.D., Lorenz, K., and Alves, E. : Radiation damage in ZnO ion implanted at 15 K. Nucl. Instrum. Methods 267, 2708 (2009).CrossRefGoogle Scholar
64.Tominaga, K., Iwamura, S., Shintani, Y., and Tada, O. : Energy analysis of high-energy neutral atoms in the sputtering of ZnO and BaTiO3. Jpn. J. Appl. Phys. 21, 688 (1982).CrossRefGoogle Scholar
65.Minami, T., Nanto, H., and Takata, S. : Highly conductive and transparent zinc oxide films prepared by rf magnetron sputtering under an applied external magnetic field. Appl. Phys. Lett. 41(10), 958 (1982).CrossRefGoogle Scholar
66.Nanto, H., Minami, T., Shooji, S., and Takata, S. : Electrical and optical properties of zinc oxide thin films prepared by rf magnetron sputtering for transparent electrode applications. J. Appl. Phys. 55(4), 1029 (1984).CrossRefGoogle Scholar
67.Tominaga, K., Yuasa, T., Kume, M., and Tada, O. : Influence of energetic oxygen bombardment on conductive ZnO films. Jpn. J. Appl. Phys. 24(8), 944 (1985).CrossRefGoogle Scholar
68.Minami, T., Oda, J-I., Nomoto, J-I., and Miyata, T. : Effect of target properties on transparent conducting impurity-doped ZnO thin films deposited by DC magnetron sputtering. Thin Solid Films 519, 385 (2010).CrossRefGoogle Scholar
69.Kluth, O., Schöpe, G., Rech, B., Menner, R., Oertel, M., Orgassa, K., and Schock, H.W. : Comparative material study on RF and DC magnetron sputtered ZnO:Al films. Thin Solid Films 502, 311 (2006).CrossRefGoogle Scholar
70.Szyszka, B. : Magnetron Sputtering of ZnO Films. Transparent Conductive Zinc Oxide: Basics and Application in Thin Film Solar Cells, edited by Ellmer, K., Klein, A., and Rech, B. (Springer, Berlin, 2008), p. 187.CrossRefGoogle Scholar
71.Horwat, D. and Billard, A. : Effects of substrate position and oxygen gas flow rate on the properties of ZnO:Al films prepared by reactive co-sputtering. Thin Solid Films 515, 5444 (2007).CrossRefGoogle Scholar
72.Ishibashi, S., Higuchi, Y., Ota, Y., and Nakamura, K. : Low resistivity indium-tin oxide transparent conductive films. II. Effect of sputtering voltage on electrical property of films. J. Vac. Sci. Technol. A 8(3), 1403 (1990).CrossRefGoogle Scholar
73.Ishibashi, S., Higuchi, Y., Ota, Y., and Nakamura, K. : Low resistivity indium-tin oxide transparent conductive films. I. Effect of introducing H2O gas or H2 gas during direct current magnetron sputtering. J. Vac. Sci. Technol. A 8(3), 1399 (1990).CrossRefGoogle Scholar
74.May, C. and Strümpfel, J. : ITO coating by reactive magnetron sputtering-comparison of properties from DC and MF processing. Thin Solid Films 351, 48 (1999).CrossRefGoogle Scholar
75.Butkhuzi, T.V., Bureyev, A.V., Georgobiani, A.N., Kekelidze, N.P., and Khulordava, T.G. : Optical and electrical properties of radical beam gettering epitaxy grown n- and p-Type ZnO single crystals. J. Cryst. Growth 117, 366 (1992).CrossRefGoogle Scholar
76.Horwat, D., Jullien, M., Capon, F., Pierson, J-F., Andersson, J., and Endrino, J.L. : On the deactivation of the dopant and electronic structure in reactively sputtered transparent Al-doped ZnO thin films. J. Phys. D 43, 132003 (2010).CrossRefGoogle Scholar
77.Utsumi, K., Matsunaga, O., and Takahata, T. : Low resistivity ITO film prepared using ultra high density ITO target. Thin Solid Films 334, 30 (1998).CrossRefGoogle Scholar
78.Tsukamoto, N., Watanabe, D., Saito, M., Sato, Y., Oka, N., and Shigesato, Y. : In-situ analyses on negative ions in the sputtering process to deposit Al-doped ZnO films. J. Vac. Sci. Technol. A 28, 846 (2009).CrossRefGoogle Scholar
79.Gassenbauer, Y., Wachau, A., and Klein, A. : Chemical and electronic properties of the ITO/Al2O3 interface. Phys. Chem. Chem. Phys. 11, 3049 (2009).CrossRefGoogle Scholar
80.Welzel, T. and Ellmer, K. : The influence of the target age on laterally resolved ion distributions in reactive planar magnetron sputtering. Surf. Coat. Technol. 205, 294 (2011).CrossRefGoogle Scholar
81.Mahieu, S., Leroy, W.P., Aeken, K.V., and Depla, D. : Modeling the flux of high energy negative ions during reactive magnetron sputtering. J. Appl. Phys. 106, 93302 (2009).CrossRefGoogle Scholar
82.Mientus, R. and Ellmer, K. : Structural, electrical and optical properties of SnO2-x:F-layers deposited by DC-reactive magnetron-sputtering from a metallic target in Ar/O2/CF4 mixtures. Surf. Coat. Technol. 98(1–3), 1267 (1998).CrossRefGoogle Scholar
83.Matsuoka, M., Hoshi, Y., and Naoe, M. : Reactive synthesis of well-oriented zinc-oxide films by means of the facing targets sputtering method. J. Appl. Phys. 63(6), 2098 (1988).CrossRefGoogle Scholar
84.Iwase, H., Hoshi, Y., and Kameyama, M. : Electrical properties of indium-tin oxide films deposited on nonheated substrates using a planar-magnetron sputtering system and a facing-target sputtering system. J. Vac. Sci. Technol. A 24(1), 65 (2006).CrossRefGoogle Scholar
85.Takeda, H., Sato, Y., Iwabuchi, Y., Yoshikawa, M., and Shigesato, Y. : Electrical and optical properties of Al-doped ZnO films deposited by hollow cathode gas flow sputtering. Thin Solid Films 517, 3048 (2009).CrossRefGoogle Scholar
86.Cebulla, R., Wendt, R., and Ellmer, K. : Aluminium-doped zinc oxide films deposited by simultaneous rf and dc excitation of a magnetron plasma: Relationships between plasma parameters and structural and electrical properties of the films. J. Appl. Phys. 83, 1087 (1998).CrossRefGoogle Scholar
87.Bender, M., Trube, J., and Stollenwerk, J. : Characterization of a RF/dc-magnetron discharge for the sputter deposition of transparent and highly conductive ITO films. Appl. Phys. A Mater. Sci. Process. 69, 397 (1999).CrossRefGoogle Scholar
88.Cuomo, J.J. and Rossnagel, S.M. : Hollow-cathode-enhanced magnetron sputtering. J. Vac. Sci. Technol. A 4(3), 393 (1986).CrossRefGoogle Scholar
89.Klawuhn, E., D’Couto, G.C., Ashtiani, K.A., Rymer, P., Biberger, M.A., and Lévy, K.B. : Ionized physical-vapor deposition using hollow-cathode magnetron source for advanced metallization. J. Vac. Sci. Technol. A 18(4), 1546 (2000).CrossRefGoogle Scholar
90.Zhu, H., Bunte, E., Hüpkes, J., Siekmann, H., and Huang, S.M. : Aluminium doped zinc oxide sputtered from rotatable dual magnetrons for thin film silicon solar cells. Thin Solid Films 517, 3161 (2009).CrossRefGoogle Scholar
91.Brenning, N., Axnäs, I., Raadu, M.A., Lundin, D., and Helmersson, U. : A bulk plasma model for dc and HiPIMS magnetrons. Plasma Sources Sci. Technol. 17, 45009 (2008).CrossRefGoogle Scholar