JPH0635340B2 - Manufacturing method of ZnS sintered body and source for electron beam evaporation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a ZnS sintered body. ZnS thin film is
It is used as a phosphor thin film of an electro-optical device, for example, an AC thin film electroluminescent display. Zn according to the invention
The S sintered body is suitable as a source for electron beam evaporation for forming the above-mentioned thin film.

Conventional Technology The electron beam heating evaporation method is most widely used for forming ZnS thin films. Zn used as an evaporation source at this time
The S sintered body was obtained by sintering ZnS powder, but its relative density was about 60 to 70% because of its poor sinterability. When a ZnS sintered body having a relative density of about 60 to 70% is used as an electron beam evaporation source, a large number of tubs having the same composition as ZnS and having a grain size of 1 μm or more are generated in the formed ZnS thin film. This is because when the sintered body is heated by the electron beam irradiation, it is charged at the same time, and when the density of the sintered body is low, the particles scatter in the form of particles due to electrostatic repulsive force and adhere to the substrate. is there. The ZnS thin film produced by such a tab is
For example, when it is used as a fluorescent thin film for an AC thin film electroluminescent display, it becomes a source of dielectric breakdown or a chemical solution enters from near the tube during the process such as electrode patterning, resulting in uneven brightness and poor uniformity of light emission. To do.

Therefore, there is an attempt to use a vapor deposition source sintered by a hot pressing method in order to increase the density of the sintered body, but this method has a difficulty in producing a large number of sintered bodies and is not industrial.

On the other hand, as a method for obtaining a high-density ZnS sintered body, a Zn compound having an average particle diameter of 0.5 μm and a Ba compound, for example, BaCl ₂ are added to a ZnO powder.
Addition of 03 mol% or more, molding at a pressure of 800 kg / cm ² and sintering at a temperature of 1000 ° C. or more in an atmosphere containing H ₂ S may give a sintered body having a relative density of 90% or more. Reported (The Journal of the American Ceram
ic Society, Vol. 65, No. 2, pp. c18 to c19 (1982)).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above report, a relatively small compact (16 mm diameter,
Only the experimental examples for 3 mm thickness) are described. ZnS
The sintered body for forming a thin film has a diameter of 25 mm and a thickness of 20 mm.
Something of a size is usually required. Therefore, before sintering, it is necessary to prepare a molded body having a diameter of 30 mm and a thickness of 25 mm by press molding. When press molding is carried out using an ordinary mold in order to create a molded body of such a size, 600 kg due to the inherent poor moldability of ZnS powder and the use of a suitable organic resin-based binder.
It is very difficult to produce a complete molded body that does not cause lamination or chipping at a pressure of / cm ² or more. 600
Relative density of 90 unless press-molded at a pressure of kg / cm ² or more
% Or more of the sintered body is not desired, and if a sintered body having lamination even if the density is partially high is used as a contact source, a grit is likely to occur in the ZnS thin film. The reason why the organic resin-based binder cannot be used is that the heat treatment atmosphere for sintering needs to be a non-oxidizing atmosphere of Ar (or N ₂ ) and H ₂ S. When an acrylic binder is used, there is a disadvantage that carbon remains in the sintered body after firing.

Means for Solving the Problems In the present invention, ZnS powder added with a Ba component is molded with a mold using pure water as a binder at a pressure of 50 to 200 kg / cm ² , and then by cold isostatic pressing. 600 kg / cm ²
It is pressed with the above pressure to obtain a final molded body, and this is made into H ₂ S.
Sintering is performed at a temperature of 1000 ° C. or higher in an inert gas atmosphere containing a gas.

Working ZnS powder with Ba component added, using pure water as binder 5
When molding with a mold at a pressure of 0 to 200 kg / cm ² ,
Even if it has a disk shape with a diameter of 30 mm and a thickness of 25 mm, no chipping or lamination occurs. Since this molded body does not easily break, it can sufficiently withstand the strength in the subsequent manufacturing process.

The proportion of pure water added as a binder is appropriately 5 to 20% by weight with respect to the ZnS powder. If it is less than 5% by weight, lamination and chipping are likely to occur, and if it exceeds 20% by weight, water seeps out during molding.

Ba components added to ZnS powder include BaCl ₂ , Ba (NO ₃ ) ₃ , B
It is possible to use aCO ₃ , Ba (OH) ₂ , BaS and the like, and the effect is exhibited when the addition ratio thereof is 0.03 mol% or more with respect to ZnS.

Next, 600 kg of the above-mentioned molded body is subjected to cold isostatic pressing.
/ Cm ² or more pressure, and by sintering this in an inert gas containing H ₂ S at a temperature of 1000 ° C. or more,
A sintered body having a relative density of 90% or more can be obtained.

By using the ZnS sintered body having a relative density of 90% or more obtained as described above as an electron beam evaporation source, it is possible to prevent scattering of particulate particles from the source due to electrification by an electron beam. A flat ZnS thin film can be prepared.

The ZnS sintered body containing the Ba component was used as the evaporation source for ZnS.
It was confirmed that even when the thin film was formed, ZnS was preferentially evaporated and the Ba component remained in the source, and was hardly mixed in the ZnS thin film. Therefore, the Ba component may be added in a large amount in order to improve the sinterability, but it is not necessary to add it more than necessary, so 1 mol% is appropriate.

Example 10 To a ZnS powder added with 0.03 mol% of BaCl ₂ , 10 wt% of pure water was added as a binder. Using a mold, pressure of 100 kg / cm ² at a diameter of 30 mm and a thickness of about 25 m
A large number of disk-shaped molded bodies of m were prepared. As described above, under these conditions, a complete molded body without any lamination or chipping can be obtained. Subsequently, the above-mentioned molded body was pressed at various hydrostatic pressures of 400 to 2000 kg / cm ² using the cold isostatic molding method to prepare a final molded body. The final compact including the sample which was not subjected to cold isostatic pressing was subjected to 10% H ₂ S (20%)-Ar (80%) atmosphere.
Heat treatment was performed for 1 hour at two temperatures of 00 ° C. and 1100 ° C. to prepare a sintered body. The relative density of the sintered body prepared under various conditions was measured and summarized in the following table. The sintered body was perfect with no lamination or chipping.

As shown in the table, 1 at a sintering temperature of 1000 ° C.
300 kg / cm ² or more, 6 at a sintering temperature of 1100 ° C
Relative density of 90 if pressed with hydrostatic pressure of 00 kg / cm ² or more
% Or more of the sintered body is obtained. The pressure effect of cold isostatic pressing is 2000 kg / cm ² and tends to be almost saturated. In the experiment of the table, the addition ratio of BaCl ₂ is 0.03 mol%, but 0.1
When mol% of BaCl ₂ was added, a sintered body having a relative density of 90% was obtained at a sintering temperature of 1000 ° C. and a hydrostatic pressure of 600 kg / cm ² .

When the sintering temperature was 1200 ° C, a sintered body having a relative density almost the same as that at 1100 ° C was obtained. Also Zn
Ba compound to be added to the S powder, regardless of the type of anion, Ba (NO ₃₎ had _{2, BaCO 3, Ba (OH} ) 2, BaS any effect.

Next, when a ZnS thin film was formed by using the ZnS sintered body having a relative density of 90% or more obtained above as a vapor deposition source of an electron beam vapor deposition method, no tab was formed in the thin film. When a sintered body having a relative density of about 80% was used, no bud was formed or not. At 60 to 70%, tubs were almost certainly formed.

EFFECTS OF THE INVENTION According to the manufacturing method of the present invention, a high density ZnS sintered body can be obtained in large quantities without the need for hot pressing. Further, by using the ZnS sintered body produced by the method of the present invention as a vapor deposition source for electron beam vapor deposition, a uniform and flat ZnS thin film can be formed.

Claims (5)

[Claims] 1. A ZnS powder containing a Ba component is press-molded with pure water as a binder at a pressure of 50 to 200 kg / cm ² using a mold, and then 600 kg by cold isostatic pressing.
Pressed at a pressure of / cm ² or more to form a molded body, and this molded body is heated to 1000 ° C. in an inert gas atmosphere containing H ₂ S gas.
A method for producing a ZnS sintered body, which is characterized by sintering at the above temperature. 2. The Ba component is BaCl ₂ , Ba (NO ₃ ) ₂ , Ba (OH) ₂ , BaCO.
_The method for producing a ZnS sintered body according to claim 1, wherein the ZnS sintered body is one selected from the Ba compound group consisting of ₃ and BaS. 3. The addition ratio of the Ba compound to the ZnS powder is 0.
The method for producing a ZnS sintered body according to claim 2, wherein the content is 03 to 1.0 mol%. 4. The method for producing a ZnS sintered body according to claim 1, wherein the proportion of pure water added to the binder is 5 to 20% by weight based on the ZnS powder. 5. A source for electron beam evaporation, comprising a ZnS sintered body having a relative density of 90% or more produced by the method of claim 1.