"As disclosed in JP 06-248427 (A), JP 2006-117462 (A), JP 2007-56351 (A) and JP 2007-56352 (A), when manufacturing a zinc oxide sintered compact tablet, sintering is performed in an air or nitrogen gas atmosphere, however, JP 06-248427 (A) discloses that, from the aspect of stability during vapor deposition, in order to improve the conductivity, performing heat treatment of the obtained zinc oxide sintered compact tablet in a reducing atmosphere such as an argon atmosphere or vacuum is effective.
"Moreover, JP 2007-56351 (A) discloses that the splashing phenomenon can be suppressed by making a half width of the diffraction peak by X-ray diffraction analysis of at least one of surface (100), surface (002) and surface (101) 0.110.degree. or less so as to equalize the particle size of the crystal particles of the zinc oxide sintered compact tablet, and JP 2007-56352 (A) discloses that the splashing phenomenon can be suppressed by reducing the closed pores in the zinc oxide sintered compact tablet. However, suppressing the splashing phenomenon with these techniques is still not sufficient."
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Problem to be Solved by the Invention
"The object of the present invention is to provide a zinc oxide sintered compact tablet that suppresses the occurrence of a splashing phenomenon when forming a film using vacuum deposition using a zinc oxide sintered compact tablet, including tablets having high resistance for which film formation typically becomes unstable, and makes it possible to stably obtain a transparent zinc oxide conductive film having no defects such as pinholes.
"Means for Solving the Problems
"The inventors of the present invention upon diligently performing research in order to solve the problems above, obtained knowledge that the splashing phenomenon can be suppressed by using a zinc oxide sintered compact tablet that is obtained by performing a uniaxial pressing of a zinc oxide granulated powder that was manufactured under special manufacturing conditions to obtain a compact, and then sintering this compact at normal pressure.
"A feature of the zinc oxide sintered compact tablet of the present invention is that in regards to the crystalline orientation of the uniaxially pressed surface which is the sublimation surface, the (103) crystalline orientation is large. By making the (103) crystalline orientation of the zinc oxide sintered compact tablet large in this way, a remarkable effect is obtained of suppressing splashing and improving the stability of film formation.
"More specifically, the zinc oxide sintered compact tablet of the present invention comprises a zinc oxide sintered compact or a zinc oxide including a dopant which has a hexagonal crystal structure, wherein when the integrated intensity of the surface (103) and surface (110) found through X-ray diffraction analysis using CuK.alpha. radiation is taken to be I.sub.(103) and I.sub.(110) respectively, the orientation of the uniaxially pressed surface that is expressed by I.sub.(103)/(I.sub.(103)+I.sub.(110)) is 0.48 or more.
"The orientation is preferably 0.5 or more, and more preferably 0.55 or more, and most preferably 0.6 or more.
"Moreover, preferably, the zinc oxide sintered compact tablet of the present invention is such that the resistivity is 1.times.10.sup.2 .OMEGA.cm or more. Furthermore, preferably the relative density is no less than 50% and no greater than 70%.
"The zinc oxide sintered compact tablet of the present invention is obtained by pressurizing granulated powder comprising a zinc oxide powder or a powder mixture of zinc oxide and an added element which will become the dopant, the granulated powder having a percentage of donut shaped secondary particles of 50% or more, to obtain a compact, then sintering the compact at normal pressure and at a temperature of 800.degree. C. to 1300.degree. C.
"Preferably, reduction treatment is performed by maintaining the normal pressure sintered compact, which was obtained by the sintering, in a vacuum at a pressure between 1.times.10.sup.-4 Pa and 1.times.10.sup.-3 Pa and at a temperature of 800.degree. C. to 1300.degree. C. for no less than 1 minute and no longer than 10 minutes.
"Particularly, the granulated powder comprising the donut shaped secondary particles is obtained by making a slurry of the base powder, which is the zinc oxide powder or the powder mixture, then spray drying the slurry at a temperature of 80.degree. C. to 100.degree. C. and adjusting the discharge airflow so that the percentage of donut shaped secondary particles is 50% or more.
"In this case, preferably part of the granulated powder is calcined at a temperature of 800.degree. C. to 1300.degree. C. for 1 hour to 30 hours. Moreover, preferably, the calcined granulated powder and non-calcined granulated powder are mixed and used.
"Effect of the Invention
"When using the zinc oxide sintered compact tablet of the present invention when performing film formation by the vacuum deposition method, together with being able to suppress the occurrence of the splash phenomenon and form film with a stable electric discharge, it is possible to prevent the occurrence of damaged material causing defects in the film during film formation, so work to remove damaged material is not necessary, and thus it is possible to greatly improve the productivity when forming transparent conductive film by the vacuum deposition method.
BRIEF DESCRIPTION OF THE DRAWINGS
"FIG. 1 is a drawing for explaining the surface (103) and the surface (101) in a zinc oxide sintered compact having a hexagonal crystal structure."
For more information, see this patent application: Sogabe, Kentaro. Zinc Oxide Sintered Compact Tablet and Manufacturing Method Thereof. U.S. Patent Application Serial Number 699139, filed
Keywords for this news article include: Indium, Gallium, Aluminum, Chemicals, Chemistry, Treatment, Zinc Oxide, Heavy Metals, Light Metals, Zinc Compounds,
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