Indium tin oxide (ITO) ceramic sputtering targets used for the manufacturing of transparent conductive thin films for electrodes in flat panel displays, solar cells, touch panels, antistatic films and others developed and commercially produced are described. Thanks to optimised compositions and developed technology, commercially producing large size planar and new generation rotary ceramic target components have high density (up to 99·5% of theoretical density), uniform microcrystalline structure and superior properties, e.g. low electrical resistivity. As a result, nanosized thin films produced by direct current magnetron sputtering from the developed targets have uniform nanocrystalline or amorphous structures and superior transmittance (>90%) and low electrical resistivity. The morphology and properties of these films have been studied, depending on the film processing features. The benefits of the developed ITO rotary targets for industrial nanosized film processing (e.g. significant increase in process efficiency, about three times higher target utilisation, practically no nodule formation and particle redeposition during sputtering and reduced processing cost) are outlined.
HambergI, GranquistCG: ‘Evaporated Sn-doped In2O3 films: basic optical properties and applications to energy-efficient windows’, J. Appl. Phys., 1986, 60, R123–R160.
8.
CastanedaL: ‘Present status of the development and application of transparent conductors oxide thin solid films’, Mater. Sci. Appl., 2011, 2, 1233–1242.
9.
UtsumiK, MatsunagaO, TakahataT: ‘Low resistivity ITO film prepared using the ultra high density ITO target’, Thin Solid Films, 1998, 334, 30–34.
10.
UtsumiK, IigusaH, TokumaruR, SongPK, ShigesatoY: ‘Study of In2O3–SnO2 transparent and conductive films prepared by D. C. sputtering using high density ceramic targets’, Thin Solid Films, 2003, 445, (2), 229–234.
11.
FrankG, KostlinH: ‘Electrical properties and defect model of tin-doped indium oxide layers’, Appl. Phys. A, 1982, 27A, 197–206.
12.
SasakiK, SeifertHP, GaucklerLJ: ‘Electric conductivity of In2O3 solid solutions with ZrO2’, J. Electrochem. Soc., 1994, 141, (10), 2759–2768.
13.
CoxPA, FlavellWR, EgdellRG: ‘Solid-state and surface chemistry of Sn-doped In2O3 ceramics’, J. Solid State Chem., 1987, 68, 340–350.
14.
GehmanBL, JonssonS, RudolphT, SchererM, WeigertM, WernerR: ‘Influence of manufacturing process of indium tin oxide sputtering targets on sputtering behavior’, Thin Solid Films, 1992, 220, 333–336.
15.
YoshimuraR, OgawaN, IwamotoT, et al..: ‘Studies on characteristics of ITO target materials’, Tosoh SMD, Japan technical note TKN 2·003A.
16.
IshibashiS, HiguchiY, OtaY, NakamuraK: ‘Low resistivity indium-tin oxide transparent conductive films. II. Effect of sputtering voltage on electrical property of films’, J. Vac. Sci. Technol. A, 1990, 8A, (3), 1403–1406.
17.
LippensP, SegersA, HaemersJ, de GryseR: ‘Chemical instability of the target surface during DC-magnetron sputtering of ITO-coatings’, Thin Solid Films, 1998, 317, 405–408.
18.
OmataT, KitaM, OkadaH, OtsukaS, MatsuoY, OnoN, IkawaH: ‘Characterization of indium-tin oxide sputtering targets showing various densities of nodule formation’, Thin Solid Films, 2006, 503, 22–28.
19.
LewisBG, MohantyR, PaineDC: ‘Structure and performance of ITO sputtering targets’, Proc. 37th Annual Technical Conf., Boston, MA, USA, May 1994, Society of Vacuum Coaters, 432–439.
20.
StuwartADG, ThompsonMW: ‘Microphotography of surfaces eroded by ion bombardment’, J. Mater. Sci., 1969, 4, 56–60.
21.
NakashimaK, KumaharaY: ‘Effect of tin oxide dispersion on nodule formation in ITO sputtering’, Vacuum, 2002, 66, 221–226.
22.
ZhangW, ZhuG, ZhiL, YangH, YangZ, YuA, XuH: ‘Structural, electrical and optical properties of indium tin oxide thin films prepared by RF sputtering using different density ceramic targets’, Vacuum, 2012, 86, 1045–1047.
23.
de WitJHW: ‘The high temperature behavior of In2O3’, J. Solid State Chem., 1975, 13, 192–200.
24.
de WitJHW, LaheijM, ElbersPE: ‘Grain growth and sintering of In2O3’, J. Solid State Chem., 1975, 13, 143–150.
25.
LamoreauxRH, HidenbrandDL, BrewerL: ‘High-temperature vaporization behavior of oxides II. Oxides of Be, Mg, Ca, Sr, Ba, B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, and Hg’, J. Phys. Chem. Ref. Data, 1987, 16, (3), 419–443.
De BosscherW, DellaertK, LuysS, LacresA: ‘ITO coating of glass for LCDs’, Inf. Display, 2005, 21, (5), 12–15.
28.
de BosscherW, DelrueH, van HolsbekeJ, MatthewsSJ, BlondeelA: ‘Rotating cylindrical ITO targets for large area coating’, Bull. Soc. Vac. Coaters, 2005, 48, 111–115.
29.
MedvedovskiE, SzepesiCJ, YankovO, OlssonMK: ‘Rotary ITO ceramic sputtering targets for transparent conductive thin films coating’, Am. Ceram. Soc. Bull., 2008, 87, (2), 39–42.
SonJ.-W, KimD.-Y: ‘Enhanced densification of In2O3 ceramics by presintering with low pressure (5 MPa)’, J. Am. Ceram. Soc., 1998, 81, (9), 2489–2492.
32.
KimB.-C, KimS.-M, LeeJ.-H, KimJJ: ‘Effect of phase transformation on the densification of coprecipitated nanocrystalline indium tin oxide powders’, J. Am. Ceram. Soc., 2002, 85, (8), 2083–2088.
33.
LangeFF: ‘Sinterability of agglomerated powders’, J. Am. Ceram. Soc., 1984, 67, (2), 83–89.
34.
ZhaoJ, HarmerMP: ‘Effect of pore distribution on microstructure development: I, matrix pores’, J. Am. Ceram. Soc., 1988, 71, (2), 113–120.
35.
ZhaoJ, HarmerMP: ‘Effect of pore distribution on microstructure development: II, first and second generation pores’, J. Am. Ceram. Soc., 1988, 71, (7), 530–539.
36.
RahamanMN: ‘Ceramic processing and sintering’; 2007, Boca Raton, FL, CRC Taylor & Francis.
KimB.-C, LeeJ.-H, KimJ.-J, LeeHY, LeeJ.-S: ‘Densification of nanocrystalline ITO powders in fast firing: effect of specimen mass and sintering atmosphere’, Mater. Res. Bull., 2005, 40, 395–404.
39.
BatesJL, GriffinCW, MarchantDD, GarnierJE: ‘Electrical conductivity, seebeck coefficient and structure of In2O3–SnO2’, Am. Ceram. Soc. Bull., 1986, 65, (4), 673–678.
40.
NadaudN, LequeuxN, NanotM, JovéJ, RoisnelT: ‘Structural studies of tin-doped indium oxide (ITO) and In4Sn3O12’, J. Solid State Chem., 1998, 135, 140–148.
41.
VojnovichT, BrattonRJ: ‘Impurity effects on sintering and electrical resistivity of indium oxide’, Am. Ceram. Soc. Bull., 1975, 54, (2), 216–217.
42.
HewardWJ, SwensonDJ: ‘Phase equilibria in the pseudo-binary In2O3–SnO2 system’, J. Mater. Sci., 2007, 42, 7135–7140.
43.
KimS.-M, SeoKH, LeeJ.-H, KimJJ, LeeHY, LeeJS: ‘Preparation and sintering of nanocrystalline ITO powders with different SnO2 content’, J. Eur. Ceram. Soc., 2006, 26, 73–80.
44.
TangS, YaoJ, ChenJ, LuoJ: ‘Preparation of indium tin oxide (ITO) with a single-phase structure’, J. Mater. Proc. Technol., 2003, 137, 82–85.
45.
KameiM, ShigesatoY, TakakiS: ‘Origin of characteristic grain–subgrain structure of tin-doped indium oxide films’, Thin Solid Films, 1995, 259, (1), 38–45.
46.
LatzR, MichaelK, SchererM: ‘High conducting large area indium tin oxide electrodes for displays prepared by DC magnetron sputtering’, Jpn J. Appl. Phys., 1991, 30, (2A), L.149–L.151.
47.
SongPK, AkaoH, KameiM, ShigesatoY: ‘Preparation and crystallization of tin-doped and undoped amorphous indium oxide films deposited by sputtering’, Jpn J. Appl. Phys., 1999, 38, (9A), 5224–5226.
48.
GuillenC, HerreroJ: ‘Polycrystalline growth and recrystallization process in sputtered ITO thin films’, Thin Solid Films, 2006, 510, (1–2), 260–264.
49.
BetzU, OlssonMK, MarthyJ, EscolbMF, AtamnyF: ‘Thin films engineering of indium tin oxide: large area flat panel displays application’, Surf. Coat. Technol., 2006, 200, (20–21), 5751–5759.
50.
GheidariAM, BehafaridF, KaveiG, KazemzadM: ‘Effect of sputtering pressure and annealing temperature on the properties of indium tin oxide thin films’, Mater. Sci. Eng. B, 2007, B136, 37–40.
51.
Trejo-CruzC, Mendoza-GalvanA, Lopez-BeltranAM, Gracia-JimenezM: ‘Effects of air annealing on the optical, electrical and structural properties of indium-tin oxide thin films’, Thin Solid Films, 2009, 517, (6), 4615–4620.
52.
MedvedovskiE, SzepesiCJ, LippensP, LeitnerK, LinsbodR, HellmichA, KrockW: ‘ITO thin film coatings obtained from developed ceramic rotary sputtering targets’, in ‘Advanced processing and manufacturing technologies for structural and multifunctional materials III’, (ed. T. Ohji and M. Singh), Vol. 30, (8), 93–99; 2009, New York, Wiley.
