CN111592033A - A kind of preparation method of target grade gallium oxide - Google Patents

Abstract

The invention relates to a preparation method of target grade gallium oxide, and belongs to the technical field of semiconductor materials. The present invention prepares ellipsoid, particle size by simultaneously adding A solution and B solution into the bottom solution C solution, and simultaneously limiting the reaction temperature, the concentration of A solution and B solution, the feeding speed of A solution and B solution, and the type of precipitant. D50=1.5～2μm gallium oxide. The gallium oxide prepared by the present invention has higher fluidity and dispersibility than rod-shaped gallium oxide, so as to meet the target use. And the gallium oxide prepared by the invention has the following characteristics: high specific surface area, BET=10～15g/cm ² ; high purity, which can reach 99.995%; small particle size, D50=1.5～2μm.

Description

A kind of preparation method of target grade gallium oxide

technical field

The invention relates to a preparation method of target grade gallium oxide, and belongs to the technical field of semiconductor materials.

Background technique

β＝103.83°。Ga₂O₃具有优良的光致发光性能、化学和热稳定性能等特性，广泛应用于敏材料、催化剂、光电子材料和荧光粉等领域。Gallium oxide (Ga ₂ O ₃ ) is an important wide-bandgap semiconductor material, which has five crystal structures: α-Ga ₂ O ₃ , β-Ga ₂ O ₃ , γ-Ga ₂ O ₃ , ε-Ga ₂ O ₃ and δ-Ga ₂ O ₃ can be transformed into each other under certain conditions. Among them, β-Ga ₂ O ₃ is the most stable, with a monoclinic structure at room temperature and a spatial structure of C2/m.

β=103.83°. Ga ₂ O ₃ has excellent photoluminescence properties, chemical and thermal stability properties and other properties, and is widely used in the fields of sensitive materials, catalysts, optoelectronic materials and phosphors.

In recent years, the application of IGZO (Indium Gallium Zinc Oxide) in the field of TFT-LCD displays has reduced the number of transistors and improved the light transmittance of each pixel, resulting in a display with a higher level of energy efficiency and higher efficiency. At present, the radio frequency/direct current (RF/DC) sputtering system is the mainstream thin film growth equipment. In addition to the thin film deposition process, the factors affecting the quality of sputtered transparent conductive films are the density, conductivity, grain size, microstructure and Purity plays a vital role. For example, the density of the target is low, that is, there are micropores on the surface or inside of the target, and the coating process will cause bulges on the surface of the target, causing the local energy of the target to be too high, and the oxygen ions are hit into a free state, forming a high-resistance area, resulting in some Microparticles get into the film and reduce the quality of the film, thus affecting the stability of the coating made.

_At present, the _{IGZO sputtering} targets sold in the commercial market are mainly sintered by solid _- phase reaction hot pressing. and other steps to prepare an IGZO target for sputtering. This preparation method is simple to operate, but the uniformity of mechanical ball milling is affected by the particle size and morphology of each powder. The particle size, morphology, fluidity and dispersibility of In ₂ O ₃ , ZnO and Ga ₂ O ₃ powders play a decisive role in the homogenization effect and the hot pressing process.

Chinese patent application CN108821329A discloses a method for preparing high-purity gallium oxide. The method uses a mixed solution of sulfuric acid and hydrogen peroxide to dissolve metal gallium to obtain a gallium sulfate solution, obtains high-purity gallium sulfate crystals through crystallization and purification, and obtains high-purity gallium sulfate crystals by calcining the sulfuric acid crystals. Gallium oxide. Although this method can obtain high-purity gallium oxide, sulfur-containing oxide gas is generated during the calcination process, and the obtained product is agglomerated, the homogeneity of the product after crushing is poor, and the sulfate decomposition temperature is high and energy consumption is high.

Chinese patent application CN107010654B discloses a monodispersed gallium oxide powder and a method for preparing a high-density ceramic target. In the invention, more than 99.99% of metal gallium is dissolved in acid, then ammonia water is added for precipitation and aging to obtain a white precipitate, and the product is obtained by washing, filtering, drying, calcining and other procedures. However, the calcination temperature of this method is high, the microscopic particles of the obtained product are easy to agglomerate, and the uniformity of the product is reduced.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a preparation method of target grade gallium oxide. material use.

In order to achieve the above purpose, the technical solution adopted in the present invention is: a preparation method of target-grade gallium oxide, the preparation method comprising the following steps:

(1) Preparation of solution A: prepare a gallium nitrate solution, dilute the gallium nitrate solution to a gallium content of 25-55g/L (0.358-0.789mol/L) and a free nitric acid concentration of 0.1%-10%, and then add a surfactant , to obtain A solution;

(2) Preparation of solution B: the precipitant is prepared into a solution with a mass fraction of 5% to 15% to obtain solution B;

(3) Bottom liquid preparation: add B solution to pure water to prepare bottom liquid C solution;

(4) Precipitation reaction: A solution and B solution are added to the bottom liquid C solution simultaneously to carry out precipitation reaction;

(5) Then, through aging reaction, centrifugal washing and calcination, target grade gallium oxide is obtained.

At present, the method commonly used in the high-purity gallium oxide industry is to precipitate gallium ions with ammonia to obtain gallium oxyhydroxide, and then calcine to obtain gallium oxide products. However, the morphology of the gallium oxide obtained by this method is rod-shaped, and the rod-shaped structure has poor fluidity and dispersibility, which affects the uniformity and density of the target material during the preparation of the target material.

The preparation method of the present invention aims to synthesize gallium oxide with an ellipsoid shape and a particle size of D50=1.5-2 μm. By adding the A solution and the B solution to the bottom liquid C solution at the same time, the reaction temperature, the concentration of the A solution and the B solution, the concentration of the A solution and the B solution are limited at the same time. The feeding speed of the solution and the B solution is to obtain its particle size D50=1.5-2 μm; by limiting the type of the precipitant and the concentration of the A solution and the B solution, the morphology is ellipsoid. The gallium oxide prepared by the present invention has higher fluidity and dispersibility than rod-shaped gallium oxide, so as to meet the target use. And the gallium oxide prepared by the invention has the following characteristics: high specific surface area, BET=10～15g/cm ² ; high purity, which can reach 99.995%; small particle size, D50=1.5～2μm.

As a preferred embodiment of the preparation method of the present invention, in the step (1), the preparation method of the gallium nitrate solution is as follows: heating the solvent, adding metal gallium and stirring; then adding nitric acid, stirring and reacting to obtain a gallium nitrate solution.

Preferably, in the step (1), the preparation method of the gallium nitrate solution is as follows: adding solvent water into the reaction kettle, raising the temperature to above 30°C, then adding metal gallium and stirring to disperse the metal gallium into droplets; Nitric acid is added into the kettle, the reaction is carried out at 40-80° C., and the stirring is continued until the reaction ends, and then unreacted solid impurities are removed by filtration to obtain a gallium nitrate solution.

Preferably, the purity of metal gallium is 99.999%, and the molar ratio of metal gallium to nitric acid is 1:4.

As a preferred embodiment of the preparation method of the present invention, the mass ratio of the metal gallium to the surfactant is (20-200):1.

As a preferred embodiment of the preparation method of the present invention, in the step (1), the surfactant is dodecylbenzenesulfonic acid (LAS), sodium alkylbenzenesulfonate (ABS), α-olefinsulfonic acid At least one of salt (AOS) and sodium secondary alkyl sulfonate (SAS).

As a preferred embodiment of the preparation method of the present invention, in the step (2), the precipitating agent is at least one of ammonia water, ammonium bicarbonate and sodium hydroxide.

More preferably, the precipitating agent is at least one of ammonia water and sodium hydroxide, and ellipsoid gallium oxide can be formed by using the precipitating agent.

More preferably, the precipitating agent is ammonia water, ellipsoidal gallium oxide can be formed by using the precipitating agent, and the post-processing operation is simple.

As a preferred embodiment of the preparation method of the present invention, in the step (3), the temperature of the bottom liquid C solution is 40-70° C., and the pH value of the bottom liquid C solution is 7.5-9.5.

As a preferred embodiment of the preparation method of the present invention, in the step (4), the reaction temperature is 40 to 70° C., the volume ratio of the bottom liquid C solution to the A solution is 1:(0.5 to 1.5), and the volume ratio of the A solution is 1: (0.5 to 1.5). The feeding speed is 1-20 L/min, and the feeding speed of solution B is regulated to maintain the pH value of the system at 7.5-9.5. After the feeding is completed, the stirring is continued for 1-3 h. The temperature of the stirring process is 40-70 ° C and the pH value is 7.5-9.5.

In the precipitation reaction, the volume ratio of the bottom liquid C solution to the A solution is 1: (0.5～1.5), the dosage range of the B solution is not limited, and the pH value of the reaction system is maintained at 7.5～9.5 by adjusting the speed of the B solution, until A The solution addition was complete.

Add solution A and solution B to the bottom solution C at the same time, and maintain the pH value of the system at 7.5-9.5 by adjusting the feeding speed of solution B to form a balanced reaction system, which is conducive to the control of particle size and morphology. In the existing preparation methods, the B solution is directly added to the A solution, the concentration of gallium ions is continuously changed, and the formed particles are of different sizes.

As a preferred embodiment of the preparation method of the present invention, in the step (5), the temperature of the aging reaction is 75-95° C., the pH value is 7.5-9.5, and the time is 1-8 h.

As a preferred embodiment of the preparation method of the present invention, in the step (5), washing is performed until the conductivity of the washing water is less than 100 μS/cm.

As a preferred embodiment of the preparation method of the present invention, in the step (5), the calcination temperature is 600-900° C., and the time is 4-12 hours.

Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention simultaneously limits the reaction temperature, the concentrations of the A solution and the B solution, the concentration of the A solution and the B solution by adding the A solution and the B solution to the bottom liquid C solution at the same time. According to the feeding speed and the type of precipitating agent, gallium oxide with ellipsoid shape and particle size D50=1.5-2 μm is prepared. The gallium oxide prepared by the present invention has higher fluidity and dispersibility than rod-shaped gallium oxide, so as to meet the target use. And the gallium oxide prepared by the invention has the following characteristics: high specific surface area, BET=10～15g/cm ² ; high purity, which can reach 99.995%; small particle size, D50=1.5～2μm.

Description of drawings

FIG. 1 is a SEM scanning electron microscope image of the gallium oxide prepared in Example 1. FIG.

FIG. 2 is a SEM scanning electron microscope image of the gallium oxide prepared in Example 2. FIG.

FIG. 3 is a SEM scanning electron microscope image of the gallium oxide prepared in Example 3. FIG.

Detailed ways

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

Example 1

A preparation method of target grade gallium oxide, comprising the following steps:

(1) Preparation of solution A: add 400L of purified water to the titanium reaction kettle, raise the temperature to 40°C, then add 35.75kg of liquid metal gallium with a purity of 99.999%, then start stirring to disperse the metal gallium, and then add premium pure gallium at a uniform speed The nitric acid is dissolved, and the molar ratio of metal gallium to nitric acid is 1:4, and the reaction is continued until the solution is clear and transparent, and purified water is added to make up the volume to 650L. The free acidity is 10%; then add 178.75g ABS to the solution, and stir until completely dissolved to obtain solution A;

(2) B solution preparation: add 800L of purified water to the precipitant storage tank, then add 200kg of 25wt% premium pure ammonia water to form a solution with a mass fraction of 5%, and after stirring evenly, obtain B solution;

(3) bottom liquid preparation: add 955L of purified water in the reactor, be warming up to 40 ℃, add 2L of solution B and adjust the pH value to 9.5 to obtain bottom liquid C solution;

(4) Precipitation reaction: A solution and B solution were added to the bottom solution C at the same time, the reaction temperature of the feeding process was controlled to be 40 ° C, the pH value was 9.5, the feeding speed of the A solution was 1L/min, and the feeding speed of the B solution was regulated. The pH value of the system was maintained at 9.5, and the stirring was continued for 2h after the addition of materials;

(5) Ageing reaction: heat up to 75°C, stop stirring, maintain the temperature at 75°C for ageing for 6 hours, and keep the pH value of the system at 9.5 during the ageing process;

Suction filtration and washing: After the aging reaction is completed, turn on the stirring to make the slurry uniform, then put the slurry into the centrifuge, and then pass into the purified water for washing until the conductivity of the washing water is less than 100 μS/cm, high-speed centrifugal drying, and discharging;

Calcination: transfer the dried material to a quartz boat, load it into a tubular atmosphere furnace, introduce a certain flow of nitrogen and oxygen mixed gas, calcinate at 600 °C for 12 hours, cool down to below 80 °C and discharge to obtain a target grade Gallium oxide 44.5kg, yield 98%.

The gallium oxide prepared in this example was sampled and sent for inspection of impurities, the ICP-MS test results are shown in Table 1, and the SEM scanning electron microscope image is shown in FIG. 1 . It can be seen from Table 1 and Figure 1 that the product has a purity of 99.995%, a particle size D50 of 1.9 μm, a specific surface area BET of 13.8 g/cm ² , and an ellipsoidal SEM morphology.

Table 1

impurity element Na Mg Ca Cr Mn Fe Co Ni Cu Zn In Pb Content/ppm 0.18 <0.1 0.13 <0.1 <0.1 0.25 <0.1 <0.1 <0.1 0.20 <0.1 0.18

Example 2

A preparation method of target grade gallium oxide, comprising the following steps:

(1) Preparation of solution A: add 400L of purified water to the titanium reaction kettle, raise the temperature to 40°C, then add 16.25kg of liquid metal gallium with a purity of 99.999%, then start stirring to disperse the metal gallium, and then add premium pure gallium at a uniform speed The nitric acid is dissolved, and the molar ratio of metal gallium to nitric acid is 1:4, and the reaction is continued until the solution is clear and transparent, and purified water is added to make up the volume to 650L. The free acidity is 5%; then add 812.5g ABS to the solution, stir until it is completely dissolved, and obtain solution A;

(2) B solution preparation: add 225L of purified water to the precipitant storage tank, then add 25kg of analytically pure sodium hydroxide to form a solution with a mass fraction of 10%, and after stirring evenly, obtain B solution;

(3) Bottom liquid preparation: add 650L purified water in the reactor, be warming up to 50 ℃, add 10mL solution B to adjust pH value to 8.0, obtain bottom liquid C solution;

(4) Precipitation reaction: A solution and B solution are added into the bottom solution C solution simultaneously, the reaction temperature of the feeding process is controlled to be 50 ° C, the pH value is 8.0, the feeding speed of the A solution is 20L/min, and the feeding speed of the B solution is regulated and controlled. The pH value of the system was maintained at 8.0, and the stirring was continued for 2h after the addition of materials;

(5) Ageing reaction: heat up to 80°C, stop stirring, keep the temperature at 80°C for ageing for 4 hours, and keep the pH value of the system at 8.0 during the ageing process;

Suction filtration and washing: After the aging reaction is completed, turn on the stirring to make the slurry uniform, then put the slurry into a centrifuge, and then pour into purified water for washing until the conductivity of the washing water is less than 10 μS/cm, high-speed centrifugal drying, and discharging;

Calcination: transfer the dried material to a quartz boat, load it into a tubular atmosphere furnace, introduce a certain flow of nitrogen and oxygen mixed gas, calcinate at 700°C for 8 hours, cool down to below 80°C and discharge to obtain a target grade Gallium oxide 31.6kg, yield 99%.

The gallium oxide prepared in this example was sampled and sent for inspection of impurities. The ICP-MS test results are shown in Table 2, and the SEM scanning electron microscope image is shown in FIG. 2 . It can be seen from Table 2 and Figure 2 that the product has a purity of 99.995%, a particle size D50 of 1.8 μm, a specific surface area BET of 14.0 g/cm ² , and an ellipsoidal SEM morphology.

Table 2

impurity element Na Mg Ca Cr Mn Fe Co Ni Cu Zn In Pb Content/ppm 0.20 <0.1 0.15 <0.1 <0.1 0.19 <0.1 <0.1 <0.1 0.23 <0.1 0.12

Example 3

A preparation method of target-grade gallium oxide, comprising the following steps:

(1) Preparation of solution A: add 400L of purified water to the titanium reaction kettle, heat up to 40°C, then add 26kg of liquid metal gallium with a purity of 99.999%, then start stirring to disperse the metal gallium, and then add high-grade pure nitric acid at a uniform speed Carry out the dissolution reaction, the molar ratio of metal gallium to nitric acid is 1:4, continue to react until the solution is clear and transparent, add purified water to make up the volume to 650L, and filter through a precision filter to obtain a gallium content of 40g/L gallium nitrate solution, free The acidity is 0.1%; then add 260g ABS to the solution, stir until completely dissolved, and obtain solution A;

(2) Preparation of solution B: add 1700L of purified water to the precipitant storage tank, then add 300kg of ammonium bicarbonate to form a solution with a mass fraction of 15%, and stir to obtain solution B;

(3) bottom liquid preparation: add 450L of purified water in the reactor, be warming up to 70 ℃, add 3L of solution B to adjust pH value to 7.5, obtain bottom liquid C solution;

(4) Precipitation reaction: A solution and B solution are added into the bottom solution C solution simultaneously, the reaction temperature of the feeding process is controlled to be 70 ° C, the pH value is 7.5, the feeding speed of the A solution is 10L/min, and the feeding speed of the B solution is regulated and controlled. The pH value of the system was maintained at 7.5, and the stirring was continued for 2h after the addition of materials;

(5) Ageing reaction: the temperature was raised to 95°C, the stirring was stopped, the temperature was maintained at 95°C for 6 hours, and the pH value of the system was maintained at 7.5 during the ageing process;

Suction filtration and washing: After the aging reaction is completed, turn on the stirring to make the slurry uniform, then put the slurry into a centrifuge, and then pour into purified water for washing until the conductivity of the washing water is less than 10 μS/cm, high-speed centrifugal drying, and discharging;

Calcination: transfer the dried material to a quartz boat, load it into a tubular atmosphere furnace, introduce a certain flow of nitrogen and oxygen mixed gas, calcinate at 900 °C for 4 hours, cool to below 80 °C and discharge to obtain a target grade Gallium oxide 45.5kg, yield 96.6%.

The gallium oxide prepared in this example was sampled and sent for inspection of impurities. The ICP-MS test results are shown in Table 3, and the SEM scanning electron microscope image is shown in FIG. 3 . It can be seen from Table 3 and Figure 3 that the product has a purity of 99.995%, a particle size D50 of 1.7 μm, a specific surface area BET of 14.5 g/cm ² , and an ellipsoidal SEM morphology.

table 3

impurity element Na Mg Ca Cr Mn Fe Co Ni Cu Zn In Pb Content/ppm 0.18 <0.1 0.13 <0.1 <0.1 0.25 <0.1 <0.1 <0.1 0.20 <0.1 0.18

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that, The technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims (10)

1. a preparation method of target grade gallium oxide, is characterized in that, described preparation method comprises the following steps: (1) A solution preparation: prepare a gallium nitrate solution, dilute the gallium nitrate solution to a gallium content of 25-55 g/L and a free nitric acid concentration of 0.1% to 10%, and then add a surfactant to obtain A solution; (2) Preparation of solution B: the precipitant is prepared into a solution with a mass fraction of 5% to 15% to obtain solution B; (3) Bottom liquid preparation: add B solution to pure water to prepare bottom liquid C solution; (4) Precipitation reaction: A solution and B solution are added to the bottom liquid C solution simultaneously to carry out precipitation reaction; (5) Then, through aging reaction, centrifugal washing and calcination, target grade gallium oxide is obtained. 2. preparation method as claimed in claim 1, is characterized in that, in described step (1), the preparation method of gallium nitrate solution is: the solvent is heated up, adds metal gallium and stirs; Then adds nitric acid, stirs reaction, promptly gets Gallium nitrate solution. 3 . The preparation method according to claim 2 , wherein the mass ratio of the metal gallium to the surfactant is (20-200):1. 4 . 4. preparation method as claimed in claim 1 is characterized in that, in described step (1), surfactant is dodecylbenzenesulfonic acid, sodium alkylbenzenesulfonate, α-olefin sulfonate, At least one of the sodium secondary alkyl sulfonates. 5. The preparation method of claim 1, wherein in the step (2), the precipitating agent is at least one of ammonia water, ammonium bicarbonate, and sodium hydroxide. 6 . The preparation method according to claim 1 , wherein in the step (3), the temperature of the bottom liquid C solution is 40-70° C., and the pH value of the bottom liquid C solution is 7.5-9.5. 7 . 7. preparation method as claimed in claim 1 is characterized in that, in described step (4), reaction temperature is 40～70 ℃, and the volume ratio of bottom liquid C solution and A solution is 1:(0.5～1.5) , the feeding speed of solution A is 1~20L/min, the feeding speed of solution B is controlled to maintain the pH value of the system at 7.5~9.5, and the stirring is continued for 1~3h after the feeding is completed. The temperature of the stirring process is 40~70℃, and the pH value is 7.5 to 9.5. 8 . The preparation method according to claim 1 , wherein in the step (5), the temperature of the aging reaction is 75-95° C., the pH value is 7.5-9.5, and the time is 1-8 h. 9 . 9 . The preparation method of claim 1 , wherein in the step (5), washing is performed until the conductivity of the washing water is less than 100 μS/cm. 10 . 10 . The preparation method according to claim 1 , wherein, in the step (5), the calcination temperature is 600-900° C., and the time is 4-12 h. 11 .

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