| Indium tin oxide (ITO) target is a kind of composite oxide material which doping tin into indium oxide,ITO film prepared by the magnetron sputtering methodwith ITO target as the raw material can be widely used in liquid crystal display, thin film transistor display and other areas of the optoelectronic. Due to the imperfection of the preparation technology of ITO target at home,the study of preparation technology of ITO target is of great significance.The ITO target was prepared by the atmospheric pressure sintering method, and a systemic research was carried out on the preparation of ITO powderand ITO target. Adding different buffer solution and dispersant improves powderperformance, and preparation of ITO target at different sintering temperature, heating rate, holding time and sintering additives optimizes the preparation technology. The properties of powder and target were characterized using TEM, XRD, BET, SEM,TG-DTA analysis instruments. The mainly working content and conclusions are as follows:(1) NH4Cl-NH3H2O solution, (NH4)2SO4-NH3·H2O solution, NH4AC solution and Na2CO3-NaHCO3 solution at different pH value were used as buffer solution to prepare ITO powder to keep the stable growth environment of precursor, meanwhile, using PVP, sodium dodecyl sulfate and soluble starch as dispersant to disperse powder. The results show that ITO powder prepared using NH4AC solution with a pH of 7 as a buffer solution has a single-phase In2O3 structure, morphology of cubic shape and better conductive performance. Using soluble starch as dispersant, ITO powder has better particle dispensability:agglomeration coefficient(AF) is 1.173.(2) Precursor prepared using NH4AC solution with a pH of 7 as a buffer solution calcined at different temperatures, the results show ITO powder calcined at 700? has even particles size and good dispensability, regular morphology. XPS were used to evaluate composition of ITO powder, and the results show In, Sn element in ITO powder exist not just the form of a single oxide also the form of composite oxide.(3) The sintering temperature, heating rate, holding time were studied systematic, the results show target sintered at 1550? for 10 h with a heating rate of 9?/min has a higher relative density of 98.7% and lower resistivity of 4×10-4?·cm.(4) Spray granulation process was carried out on the powder granulation, meanwhile, comparing the difference between the spray granulation and grinding granulation. The results show spray granulation process can improve target density, target sintered at 1550? for 6 h with a heating rate of 9?/min has a relative density of 99.1% and resistivity of 3×10-4?·cm.(5) Target was prepared by changing the sequence of debinding process and ICP process, Comparision the difference of between first debinding process and then ICP and first ICP and then debinding process. The results show that the former obviously decreases the densification behavior of target:the relative density of target for former reaches the maximum of 93.05% at 1550?, while the latter reaches the maximum of 95.95% at 1500?.(6) ITO target was prepared by adding Bi2O3, TiO2, Bi2O3-TiO2 as sintering additives. The results show that when Bi2O3 was used as sintering additives, the density of target improved significantly from 87.15% to 93.17% at 1450?, but the resistivity increased to 73.65×10-4?·cm. Continuing to heat up to 1500?, due to the evaporation of Bi2O3, resistivity decreases to 9.6 ×10-4?·cm, and density is 94.45%; when TiO2 was used as sintering additive, the density of target is 91.43% at 1450?, while resistivity decreases to 3.05 ×10-4?·cm due to vacancy mechanism; the density and resistivity of target with Bi2O3-TiO2 composite as sintering additives lies between Bi2O3 and TiO2. |
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