| Indium gallium zinc oxide thin film transistor(IGZO TFT) is one of the most promising oxide transistors. As the sputtering target required for the production of IGZO TFT, the performance of indium gallium zinc oxide(IGZO) target directly affects the quality of IGZO TFT. Currently the preparation method of IGZO target can be divided into two types according to the different raw material powders, one is to use the IGZO powder as the raw material, and the other is to use the mixed powders of indium oxide(In2O3), gallium oxide(Ga2O3), zinc oxide(ZnO) as the raw material. In this paper, ZnO and IGZO powders were synthesized through precipitation method, the research included two aspects, first, to study the preparation of ZnO with different morphologies and the growth mechanism of some complicated morphologies;Second, to synthesize the IGZO powders by using different precipitants and precipitation methods. One kind of the powder among them was used as the raw material to conduct sintering experiment. The main works are as follows:(1) Flower-like ammine zinc hydroxide chloride(ZHC-NH3) assembled by nanosheets was formed after Zinc chloride(ZnCl2) solution reacted with ammonia at 80?. The formation of flower-like structure was related to the supersaturation of solution. The flower-like ZHC-NH3 decomposed into flower-like porous ZnO after calcination, the decomposition process was strongly affected by environment humidity. ZHC-NH3 was the product that ammonia molecules intercalated into the interlayer space of(0 0 3) plane of zinc hydroxide chloride(ZHC). Flower-like ZHC-NH3 could remove the intercalated ammonia molecules by heat treatment in a water bath and transformed into sheet-like ZHC. Sheet-like ZHC decomposed into Sheet-like porous ZnO after calcination.(2) Rod-like ZnO was directly formed after ZnCl2 solution reacted with ammonia at 80?. The formation of this morphology was due to the anisotropic growth of ZnO, which grew fastest along [0 0 0 1] derection. After the above-mentioned rod-like ZnO obtained at higher temperature was naturally cooled down to room temperature, then aged at 5? for 12 h, tubular ZnO was formed. It was because the rod-like ZnO dissolved at lower temperature, and the dissolution rate of(0 0 0 1) plane was fastest.(3) Flower-like ZnO assembled by nanorods was formed after ZnCl2 solution reacted with sodium hydroxide(NaOH) solution at 50?, and the tail ends of these nanorods were tapered. The formation of flower-like morphology was due to the initially formed ZnO nuclei aggregated together, and then, grew anisotropically along [0 0 0 1] derection.(4) After ZnCl2 solution reacted with sodium carbonate(Na2CO3) and ammonium carbonate((NH4)2CO3) solution at 50 ?, respectively, zinc hydroxide carbonate Zn4(CO3)(OH)6·H2O precursors were formed in both the two system, and the uniform and equiaxed nano-ZnO could be obtained after the two precursors were calcinated.(5) The powder which basically consisted of InGaZnO4 single phase was successfully synthesized through co-precipitation method(NaOH, Na2CO3, ammonia,(NH4)2CO3 as precipitants) and mutistep precipitation method(ammonia,(NH4)2CO3) as precipitants). The optimum technology for the synthesis of the powder was to adopt mutistep precipitation method and to use ammonia as the precipitant. The powder synthesized in this way possessed better sintering performance, and the mole ratio of In, Ga, Zn elements in the powder was 1:1.041:1.004, which was closest to the theoretical value 1:1:1.(6) The amorphous IGZO powder synthesized by the optimum technology was used as the raw material to press into green bodies through die pressing and subsequent cold isostatic pressing. The green bodies were sintered at different temperatures by pressureless sintering method. The results showed that, the ceramic obtained after sintering at 1200? was basically InGaZnO4 single phase with relative density as high as 97.43%, and the crystal grains in the sintering body were fine and uniform with size below 1?m. |
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