AVS 46th International Symposium
    Thin Films Division Wednesday Sessions
       Session TF-WeA

Paper TF-WeA3
Electrical Properties and Surface Morphology of Heteroepitaxial Grown Tin-doped Indium Oxide Films Deposited by Molecular Beam Epitaxy

Wednesday, October 27, 1999, 2:40 pm, Room 615

Session: Transparent Conductive Oxides
Presenter: N. Taga, Asahi Glass Co., Ltd., Japan
Authors: N. Taga, Asahi Glass Co., Ltd., Japan
Y. Shigesato, Aoyama Gakuin University, Japan
M. Kamei, National Institute for Research in Inorganic Materials, Japan
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Heteroepitaxial growth of Sn-doped indium oxide (ITO) and non-doped indium oxide (IO) thin films was carried out on optically polished single-crystal yttria-stabilized zirconia (YSZ) substrates by molecular beam epitaxy. The surface morphology of these epitaxial films was analyzed by scanning electron microscopy and the electrical properties were measured by four-point probe method and Hall-effect measurements. The ITO and non-doped IO films showed quite different surface morphology, suggesting that Sn acted not only as dopant but also as growth modifier for IO films. The surface morphology analysis on IO and ITO films revealed that a growth rate along the <111> direction was enhanced by Sn doping. Resistivity (@rho@) of the epitaxial grown ITO films was 1.7E-4 @ohm@cm which was smaller than the @rho@ of polycrystalline ITO films (2.1E-4 @ohm@cm) deposited on glass substrate under the same deposition conditions. This result was consistent with the report on the heteroepitaxial films deposited by a conventional electron beam evaporation.@footnote 1@ The epitaxial ITO film deposited on YSZ(100) substrate showed higher carrier density N = 8.7E+20 cm@super -3@ and lower resistivity @rho@ = 1.7E-4 @ohm@cm compared with the one deposited on YSZ(111) substrate ( N = 8.0E+20 cm@super -3@, @rho@ = 1.9E-4 @ohm@cm ) deposited at simultaneously in the same batch. Such a difference between ITO(100)/YSZ(100) and ITO(111)/YSZ(111) implying that the crystal growth orientation should have large effects on the electrical properties. Sn concentration analyzed by X-ray photoelectron spectroscopy showed difference between the ITO(100) and the ITO(111), which was considered to be the one of the dominant factor for electrical properties. @FootnoteText@ @footnote 1@ N. Taga, H. Odaka, Y. Shigesato, I. Yasui, M. Kamei and T. E. Haynes, J. Appl. Phys. 80, 978 (1996).