WO2023098706A1

WO2023098706A1 - Zinc-doped indium oxide powder, sputtering target material, and preparation methods therefor

Info

Publication number: WO2023098706A1
Application number: PCT/CN2022/135311
Authority: WO
Inventors: 刘洋; 孙本双; 曾学云; 刘超飞; 刘笑开; 王之君; 刘苗; 陈杰; 舒永春; 何季麟
Original assignee: 郑州大学
Priority date: 2021-11-30
Filing date: 2022-11-30
Publication date: 2023-06-08
Also published as: CN113956022A

Abstract

Provided in the present invention are a zinc-doped indium oxide powder, a sputtering target material, and preparation methods therefor, belonging to the technical field of new materials. In the present invention, a precursor powder of a zinc-doped indium oxide is synthesized in one step using a hydrothermal method, the reaction system is stable, and the resulting zinc-doped indium oxide powder has a high purity, a uniform crystal form distribution, good dispersity and a high crystallinity; and a sputtering target material resulting from sintering of the powder has a small grain size, a uniform distribution and a high density. The present application is simple and convenient in the whole process from the preparation of the powder to forming and sintering processes, low in terms of cost, and suitable for industrial production.

Description

A kind of zinc-doped indium oxide powder, sputtering target material and preparation method thereof

technical field

The invention belongs to the technical field of new materials, and in particular relates to a zinc-doped indium oxide powder, a sputtering target and a preparation method thereof.

Background technique

Multi-component metal oxide sputtering targets with indium oxide as the main material have been widely used in the fields of electrodes, liquid crystal displays, touch panels, solar cells, and integrated optoelectronic devices. Indium tin oxide (ITO), as a traditional transparent conductive oxide, occupies a large share in the market, and the properties of the thin film made of its sputtering target have been recognized by the industry, such as low resistivity, high transmittance, easy to Etching processing, etc. However, the ITO thin film is in a crystalline state, and there are problems such as reduced film precision due to grain growth, and poor display caused by residual grains. These structural defects will limit its development in future flexible displays. In contrast, the indium zinc oxide (IZO) film is amorphous, with a smooth surface, low deposition temperature, fast etching speed, low cost of ZnO, high band gap energy (3.37eV), and is more feasible in target manufacturing. Persistence, so the application potential of IZO sputtering targets is broad.

Patent CN102653413B discloses a zinc-doped indium oxide nanometer gas-sensing material and its preparation method. The method adopted is the liquid phase precipitation method. This method has simple process and low production cost, but the powder is easy to agglomerate during the preparation process. Poor dispersion. Simultaneously its field of application differs greatly from the present invention.

Contents of the invention

In view of this, the object of the present invention is to provide a zinc-doped indium oxide powder, a sputtering target and a preparation method thereof. The reaction system of the preparation method of zinc-doped indium oxide powder provided by the present invention is stable, and the obtained powder has high purity, uniform crystal form distribution, good dispersion and high crystallinity; the sputtering target grain size obtained after the powder is sintered Small, uniform distribution, high density.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a method for preparing zinc-doped indium oxide powder, comprising the following steps:

1) After mixing the indium salt, the zinc salt, the precipitating agent and water, perform a hydrothermal reaction to obtain a precursor mixed solution; the temperature of the hydrothermal reaction is 150-250° C., and the time is 5-20 hours;

2) Washing, drying and calcining the precursor mixed liquid in the step 1) sequentially to obtain zinc-doped indium oxide powder; the calcining temperature is 400-800°C.

Preferably, in the step 1), the molar ratio of the indium atoms in the indium salt to the zinc atoms in the zinc salt is 1˜2.5:1.

Preferably, in the step 1), the indium salt is at least one of indium nitrate, indium sulfate and indium chloride.

Preferably, in the step 1), the zinc salt is at least one of zinc sulfate, zinc nitrate and zinc chloride.

Preferably, in the step 1), the precipitation agent is at least one of ammonia water, sodium hydroxide and oxalic acid.

Preferably, in the step 1), the pH value after mixing the indium salt, zinc salt, precipitation agent and water is 5-11.

The present invention also provides the zinc-doped indium oxide powder prepared by the above preparation method, the particle size of the zinc-doped indium oxide powder is 100-800 nm, and the purity is greater than 99.99%.

The present invention also provides a method for preparing a sputtering target from the zinc-doped indium oxide powder, comprising the following steps:

The zinc-doped indium oxide powder is sequentially preformed, formed and sintered to obtain a sputtering target.

Preferably, the preforming pressure is 30-80 MPa; the sintering temperature is 1450-1600° C., and the sintering time is 5-20 hours.

The present invention also provides the sputtering target prepared by the above method, the main phase of the sputtering target is Zn atoms doped into the In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , and the relative density is Greater than 99.2%.

Beneficial technical effects: the invention provides a zinc-doped indium oxide powder, a sputtering target and a preparation method thereof. The invention adopts a hydrothermal method to synthesize an indium-zinc co-doped precursor powder in one step, and the reaction system is stable , the obtained zinc-doped indium oxide powder has high purity, uniform crystal form distribution, good dispersion and high crystallinity; the sputtering target obtained after the powder is sintered has fine grain size, uniform distribution and high density. The invention has simple and convenient whole process from powder preparation to forming and sintering process, low cost and is suitable for industrialized production.

Description of drawings

Fig. 1 is the SEM picture of the zinc-doped indium oxide powder that embodiment 1 prepares;

Fig. 2 is the XRD pattern of the zinc-doped indium oxide powder prepared in embodiment 1;

3 is an SEM image of the IZO sputtering target prepared in Example 1.

Detailed ways

In the invention, after mixing indium salt, zinc salt, precipitating agent and water, hydrothermal reaction is carried out to obtain precursor mixed solution.

In the present invention, the indium salt is preferably at least one of indium nitrate, indium sulfate and indium chloride, more preferably indium nitrate. The indium salt in the present invention is preferably mixed in the form of an indium salt solution, and the concentration of indium ions in the indium salt solution is preferably 0.1-2 mol/L, more preferably 0.5-1.5 mol/L.

In the present invention, when the indium salt is preferably indium nitrate, the indium nitrate is preferably prepared by reacting nitric acid solution with indium. In the present invention, the concentration of the nitric acid solution is preferably 8-14 mol/L.

In the present invention, the zinc salt is preferably at least one of zinc sulfate, zinc nitrate and zinc chloride. In the present invention, the zinc nitrate is preferably mixed with the indium salt solution in solid form. In the present invention, the molar ratio of the indium atoms in the indium salt to the zinc atoms in the zinc salt is preferably 1-2.5:1, more preferably 1.5-2:1. The present invention ensures that the zinc atoms are doped into the indium oxide by controlling the molar ratio of the indium atoms and the zinc atoms, and at the same time, a slight excess is beneficial to the subsequent densification process of the target material.

In the present invention, the precipitating agent is preferably at least one of ammonia water, sodium hydroxide and oxalic acid. In the present invention, the amount of the ammonia water is preferably such that the pH value of the mixed system obtained by mixing the indium salt, the zinc salt, the precipitating agent and water is 5-11, preferably 7-9. In the present invention, zinc-doped indium oxide powders with different shapes can be obtained by adjusting the pH value of the mixed system.

In the present invention, the temperature of the hydrothermal reaction is 150-250°C, preferably 180-200°C; the time of the hydrothermal reaction is 5-20h, preferably 10-15h. Specifically, the present invention preferably mixes the indium salt, zinc salt, precipitant, and water to obtain a mixed system that is heated from room temperature to the hydrothermal reaction temperature for hydrothermal reaction, and the rate of heating and temperature rise is preferably 1 to 3°C/min , more preferably 2°C/min. The invention can obtain the zinc-doped indium oxide composite nano-powder precursor with excellent crystallization performance through hydrothermal reaction.

After the precursor mixed solution is obtained, the present invention washes, dries and calcines the obtained precursor mixed solution in sequence to obtain the zinc-doped indium oxide powder; the temperature for the calcination is preferably 400-1000° C., more preferably 600-1000° C. 800°C.

In the present invention, the detergent used for washing is preferably deionized water; the conditions for the end of washing are preferably washing until the pH value of the washing filtrate is between 7 and 8, and the conductivity is ≤50 μS/cm. In the present invention, there is no special limitation on the specific method of washing, and the methods well known to those skilled in the art can be selected.

In the present invention, the drying temperature is preferably 75-85°C, more preferably 80°C.

In the present invention, the drying further includes successively pulverizing and sieving the precursor powder obtained after drying. In the present invention, the particle size of the precursor powder is preferably 40-150 nm, more preferably 60-120 nm. The present invention has no special limitation on the specific method of crushing and sieving, as long as the particle size of the precursor powder reaches the required value.

In the present invention, the calcination temperature is preferably 400-1000°C, more preferably 600-800°C. The invention obtains the zinc-doped indium oxide composite nano-powder with excellent crystallization performance through calcination.

The invention adopts the hydrothermal method to synthesize the precursor powder of zinc-doped indium oxide in one step, the reaction system is stable, the obtained powder has high purity, uniform crystal form distribution, good dispersibility and high crystallinity.

The present invention also provides the zinc-doped indium oxide powder prepared by the above-mentioned preparation method, the particle size distribution of the zinc-doped indium oxide powder is 60-120 nm, and the purity is greater than 99.99%.

In the present invention, the pressure of the preforming is preferably 30-80 MPa, more preferably 50-60 MPa; the forming is preferably cold isostatic pressing or pressure grouting, and the pressure of the cold isostatic pressing Preferably it is 180-300 MPa, more preferably 220-280 MPa; said pressure grouting pressure is preferably 0.1-0.5 MPa, more preferably 0.2-0.4 MPa.

In the present invention, the sintering temperature is preferably 1450-1600°C, preferably 1500-1550°C, most preferably 1550°C; the sintering time is preferably 5-20h, more preferably 10-15h; The sintering atmosphere is preferably air, oxygen or argon. Specifically, the sintering is preferably heating the green body obtained after cold pressing to a sintering temperature for sintering. In the present invention, the heating rate is preferably 1-3°C/min, more preferably 2°C/min.

In the present invention, when the sintering temperature is lower than 1450°C, the sputtering target cannot be densified and there are holes; when the sintering temperature is higher than 1600°C, the volatilization of ZnO will lead to a decrease in the target density or a deviation in the composition, etc. defect.

The sputtering target obtained by the invention has fine grain size, uniform distribution and high density. The invention has simple and convenient whole process from powder preparation to forming and sintering process, low cost and is suitable for industrialized production.

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

Example 1

The preparation method of indium nitrate solution

The nitric acid solution is reacted with metal indium to prepare an indium nitrate solution; the concentration of indium nitrate in the reaction solution is calculated according to the mass loss before and after the reaction of indium ingots; deionized water is added to the reaction solution so that the concentration of indium nitrate is 1.5mol/L, Indium nitrate solution was obtained.

Preparation method of zinc-doped indium oxide powder

1) Mix 359g of ZnSO ₄ ·7H ₂ O solid with 833mL of the above indium nitrate solution (In/Zn=1:1), add deionized water until the total volume of the solution is 2500mL, stir at room temperature to completely dissolve the solid to obtain a mixed liquid, wherein the indium atom content is 1.25mol;

2) Slowly add 25% ammonia water to the mixed solution until the pH value of the solution is 7, transfer to a hydrothermal reactor and react at 180°C for 12 hours to obtain a precursor mixed solution containing indium hydroxide and zinc hydroxide; the heating rate of the reactor is 1°C/min;

3) Wash the precursor mixed solution obtained in step 2) with deionized water until the pH value of the washing filtrate is 7 and the electrical conductivity is less than or equal to 20 μS/cm, and the washing is completed, and the washed solution is dried at 80 ° C, And use jet mill to pulverize and sieve, so that the particle size of the precursor powder is 100-800nm;

4) Calcining the precursor powder obtained in step 3) at 400° C. for 2 hours to obtain zinc-doped indium oxide powder.

Sputtering target preparation method:

Preform the zinc-doped indium oxide powder obtained above at 30 MPa and perform cold isostatic pressing at 180 MPa to make a green body with a diameter of 120 mm and a height of 10 mm; place the obtained green body in a sintering furnace and heat it in an air atmosphere The temperature was kept at 1550° C. for 20 hours, and the heating rate was 3° C./min to obtain an IZO sputtering target.

Fig. 1 is the SEM image of the zinc-doped indium oxide powder prepared in Example 1. It can be seen from its microstructure that the powder has good dispersibility. Figure 2 is the XRD pattern of the zinc-doped indium oxide powder prepared in Example 1. It can be seen that the diffraction peaks of the powder are consistent with the diffraction peaks in In ₂ O ₃ and ZnO standard cards, and there are no other miscellaneous peaks. , and the diffraction peaks are very sharp, indicating that the obtained In ₂ O ₃ -ZnO powder has high purity and good crystallinity. Figure 3 is the SEM image of the IZO sputtering target prepared in Example 1. It can be seen from Figure 3 that the IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ , and the secondary phase It is Zn ₃ In ₂ O ₆ , the relative density is 99.4%, and the average grain size is 6μm.

Example 2

The preparation method of indium nitrate solution: identical with embodiment 1.

The preparation method of zinc-doped indium oxide powder: in step 2), slowly add 25% ammonia water to the mixed solution until the pH value of the solution is 5, and the other steps are exactly the same as in Example 1.

The preparation method of the sputtering target: the zinc-doped indium oxide powder obtained in this example is used as the raw material, and the rest is exactly the same as that of Example 1.

The IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , the relative density is 99.2%, and the average grain size is 8 μm.

Example 3

The preparation method of indium nitrate solution: identical with embodiment 1.

The preparation method of zinc-doped indium oxide powder: in step 2), slowly add 25% ammonia water to the mixed solution until the pH value of the solution is 9, and the other steps are exactly the same as in Example 1.

The IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , the relative density is 99.6%, and the average grain size is 4 μm.

Example 4

The preparation method of indium nitrate solution: identical with embodiment 1.

The preparation method of zinc-doped indium oxide powder: In step 2), slowly add 25% ammonia water to the mixed solution until the pH value of the solution is 11, and the other steps are exactly the same as in Example 1.

The IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , the relative density is 99.3%, and the average grain size is 5 μm.

Example 5

The preparation method of indium nitrate solution: identical with embodiment 1.

The preparation method of zinc-doped indium oxide powder:

1) Mix 23.9g ZnSO ₄ ·7H ₂ O solid with 83.3mL indium nitrate solution (In/Zn=1.5:1), add deionized water until the total volume of the solution is 250mL, stir at room temperature to completely dissolve the solid to obtain a mixed liquid, wherein the indium atom content is 0.125mol;

2) Slowly add 25% ammonia water to the mixed solution until the pH value of the solution is 9, transfer to a hydrothermal reactor and react at 180°C for 12 hours to obtain a precursor mixed solution containing indium hydroxide and zinc hydroxide; the heating rate of the reactor is 1°C/min;

All the other steps are identical to Example 1.

IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , the relative density is 99.1%, and the average grain size of the target is 9 μm .

Example 6

The preparation method of indium nitrate solution: identical with embodiment 1.

The preparation method of zinc-doped indium oxide powder:

1) Mix 14.4g ZnSO ₄ ·7H ₂ O solid with 83.3mL indium nitrate solution (In/Zn=2.5:1), add deionized water until the total volume of the solution is 250mL, stir at room temperature to completely dissolve the solid to obtain a mixed liquid, wherein the indium atom content is 0.125mol;

All the other steps are identical to Example 1.

The IZO sputtering target can achieve densification, the main phase is Zn atoms doped to In ₂ O ₃ phase, the rectangular secondary phase is Zn ₃ In ₂ O ₆ , the relative density is 99.4%, and the average grain size is 7 μm.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims

A method for preparing zinc-doped indium oxide powder, characterized in that it comprises the following steps:

1) After mixing the indium salt, the zinc salt, the precipitating agent and water, perform a hydrothermal reaction to obtain a precursor mixed solution; the temperature of the hydrothermal reaction is 150-250° C., and the time is 5-20 hours;

2) Washing, drying and calcining the precursor mixed liquid in the step 1) sequentially to obtain zinc-doped indium oxide powder; the calcining temperature is 400-800°C.
The preparation method according to claim 1, characterized in that, in the step 1) the molar ratio of the indium atoms in the indium salt to the zinc atoms in the zinc salt is 1-2.5:1.
The preparation method according to claim 1, characterized in that the indium salt in the step 1) is at least one of indium nitrate, indium sulfate and indium chloride.
The preparation method according to claim 1, characterized in that the zinc salt in the step 1) is at least one of zinc sulfate, zinc nitrate and zinc chloride.
The preparation method according to claim 1, characterized in that, in the step 1), the precipitation agent is at least one of ammonia, sodium hydroxide and oxalic acid.
The preparation method according to claim 1 or 5, characterized in that the pH value after mixing the indium salt, zinc salt, precipitating agent and water in the step 1) is 5-11.
The zinc-doped indium oxide powder prepared by the preparation method according to any one of claims 1 to 6 is characterized in that the particle size of the zinc-doped indium oxide powder is 100-800 nm, and the purity is greater than 99.99%.
A method for preparing a sputtering target from zinc-doped indium oxide powder according to claim 7, characterized in that it comprises the following steps:

The zinc-doped indium oxide powder is sequentially preformed, formed and sintered to obtain a sputtering target.
The method according to claim 8, characterized in that the preforming pressure is 30-80 MPa; the sintering temperature is 1450-1600° C., and the sintering time is 5-20 hours.
The sputtering target prepared by the method according to any one of claims 8 to 9, characterized in that the main phase of the sputtering target is Zn 3 In 2 O 6 , and the rectangular residual phase is In 2 O 3. The relative density is greater than 99.2%, and the average grain size is 3-10 μm.