A method for preparing high-purity gallium, indium, and aluminum amino compounds

Abstract

The present invention discloses a preparation method of high-purity amino gallium, indium, and aluminum compounds, belonging to the technical field of semiconductor chips, and comprising the following steps: The first step is to prepare a lithium dimethylamide n-hexane suspension; the second step is to prepare one of crude tris(dimethylamino)gallium dimer, crude tris(dimethylamino)indium dimer, and crude tris(dimethylamino)aluminum dimer; the third step is to purify the crude tris(dimethylamino)metal compound by stepwise cooling recrystallization to obtain high-purity amino gallium, indium, and aluminum compounds; the present invention purifies the crude tris(dimethylamino)metal compound by stepwise cooling recrystallization, which not only has high efficiency and simple process, but also has a moderate crystallization rate of the product during the recrystallization process, will not form impurity encapsulation, has good crystal form of the product, and the purity is ≥99.9999% (6N), meeting the purity requirements for ALD / CVD film deposition of semiconductor chips.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor chips, and particularly relates to a preparation method of high-purity gallium, indium, and aluminum amino compounds. Background Art

[0002] The ALD / CVD deposition process of semiconductor chips has strict requirements for the purity of precursor compounds, and the metal content requirement is not less than 99.9999%. The dimethylamino compounds of gallium, aluminum, and indium can be used as precursors for the ALD or CVD deposition of semiconductor chips to prepare high-dielectric-constant metal nitride and / or metal oxide film layers. The purity of the precursor chemical materials is a key index determining whether they can be used for the deposition preparation of semiconductor chips. Among them, the synthesis method and purification method of dimethylamino metal compounds have a great influence on the purity of dimethylamino metal compounds.

[0003] The dimethylamino compound can be prepared by reacting a metal halide with a lithium amide, sodium amide, or potassium amide in a hydrocarbon solvent at a molar ratio of 1:3. After the obtained crude product mixture is subjected to solid-liquid separation to remove solid impurities, the corresponding crude product is obtained by removing the solvent, and the crude product is purified to obtain a high-purity product. The purification method includes sublimation or recrystallization methods.

[0004] Chinese Patent CN101161766B (Nanocrystalline Phosphors and Coated Nanocrystalline Phosphors and Their Preparation Methods) describes the application of tris(dimethylamino)gallium dimer, tris(dimethylamino)indium dimer, and tris(dimethylamino)aluminum dimer in nanophosphor materials, and briefly introduces that this type of product is prepared from lithium dimethylamide and gallium trichloride / indium / aluminum in a hexane solution, and elaborates that the semiconductor microcrystals prepared from this compound have the characteristics of high luminous efficiency and excellent reliability. However, this document (1) does not give a specific preparation method; (2) does not have a product purification process, nor does it involve a preparation method of high-purity products.

[0005] Therefore, it is necessary to provide a preparation method of high-purity gallium, indium, and aluminum amino compounds. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of high-purity gallium, indium, and aluminum amino compound products with a product purity of 6N (99.9999%), and the purification method of the compounds is more prominent.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A preparation method of high-purity gallium, indium, and aluminum amino compounds, comprising the following steps:

[0009] First step, preparing a lithium dimethylamide n-hexane suspension;

[0010] Step 2: Prepare a crude product of a tris(dimethylamino)metal compound, i.e., one of a crude product of tris(dimethylamino)gallium dimer, a crude product of tris(dimethylamino)indium dimer, and a crude product of tris(dimethylamino)aluminum dimer;

[0011] Step 3: Purify the crude product of the tris(dimethylamino)metal compound by the stepwise cooling recrystallization method to obtain high-purity amino gallium, indium, and aluminum compounds.

[0012] As a further scheme of the present invention, the preparation steps of the lithium dimethylamide n-hexane suspension are as follows:

[0013] Under a protective gas atmosphere, add n-butyllithium and n-hexane to a reaction kettle, start stirring, control the rotation speed at 100 - 200 rpm, introduce dimethylamine under stirring, control the reaction temperature at 20 - 60 °C, and after the introduction of dimethylamine is completed, continue stirring and reacting for 1 h at 20 - 60 °C to obtain a lithium dimethylamide n-hexane suspension;

[0014] Among them, the dosage ratio of n-butyllithium, n-hexane, and dimethylamine is 31.48 mol: 20 kg: 32.0 mol, the introduction time of dimethylamine is controlled at 1.5 - 3 h, and using dimethylamine and n-butyllithium as raw materials to prepare lithium dimethylamide, the reaction process is as follows:

[0015] Me2NH+Li n Bu→LiNMe2+C4H 10 , Me is methyl, n Bu is n-butyl.

[0016] As a further scheme of the present invention, the preparation steps of the crude product of the tris(dimethylamino)metal compound are as follows:

[0017] Under a protective gas atmosphere, mix a trihalide and toluene to form a trihalide toluene solution, and dropwise add the trihalide toluene solution to a reaction kettle containing a lithium dimethylamide n-hexane suspension under stirring. During the dropping process, control the reaction temperature at 40 - 60 °C. After the dropping is completed, stir and react at 60 °C for 3 h to obtain a mother liquor. Filter the mother liquor, and remove all solvents from the filtrate under reduced pressure at 60 °C to obtain a crude product of the tris(dimethylamino)metal compound;

[0018] Among them, the dosage ratio of the trihalide, toluene, and lithium dimethylamide is 9.54 mol: 4 kg: 31.48 mol, and the trihalide is one of gallium trichloride, indium trichloride, aluminum trichloride, gallium tribromide, indium tribromide, and aluminum tribromide; using lithium dimethylamide to react with the trihalide to prepare a crude product of the tris(dimethylamino)metal compound, and the specific reaction process is as follows:

[0019] MX3 + 3LiNMe2 → M(NMe2)3 + MX3, where X = Cl, Br; M = Ga, In, Al.

[0020] As a further aspect of the present invention, the crude product of tris(dimethylamino)metal compound is purified by the stepwise cooling recrystallization method, and the specific operation steps are as follows:

[0021] Under the atmosphere of protective gas, the crude product of tris(dimethylamino)metal compound is added to the reaction kettle, and then dry n-hexane is added for the first time. The temperature is raised to 60 °C and stirred for 1 h, and then transferred to a three-necked flask for the first gradient cooling recrystallization process, which is specifically as follows: The three-necked flask is sealed and placed in a cold bath. The refrigeration temperatures of the cooling bath are set to six temperature segments of 10 °C, 0 °C, -10 °C, -20 °C, -30 °C, and -40 °C in sequence, and each temperature segment is treated for 60 min. After the first gradient cooling recrystallization is completed, the crystallization mother liquor is transferred to the waste liquid bucket. The three-necked flask is removed from the cold bath, and dry n-hexane is added to the three-necked flask again. After heating to 60 °C until all the crystals are dissolved, the temperature is lowered to room temperature for the second gradient cooling recrystallization. After the second gradient cooling recrystallization is completed, the mother liquor is separated, and the obtained crystalline product is vacuum dried at room temperature for 3 h.

[0022] As a further aspect of the present invention, the protective gas is nitrogen or argon.

[0023] As a further aspect of the present invention, the mass ratio of the crude product of tris(dimethylamino)metal compound, the dry n-hexane added for the first time, and the dry n-hexane added for the second time is 1.6 - 2.5:6:2.5.

[0024] As a further aspect of the present invention, the dry n-hexane has a water content of less than 60 ppm.

[0025] As a further aspect of the present invention, the operation steps of the second gradient cooling recrystallization are the same as those of the first gradient cooling recrystallization.

[0026] The beneficial effects of the present invention:

[0027] 1. The purity of the tris(dimethylamino)gallium dimer, tris(dimethylamino)indium dimer, and tris(dimethylamino)aluminum dimer prepared by the present invention is ≥99.9999% (6N), meeting the purity requirements for ALD / CVD film deposition of semiconductor chips.

[0028] 2. The present invention purifies the crude product of tris(dimethylamino) metal compound by stepwise cooling recrystallization. This purification method is not only highly efficient but also has a simple process. The purification process is carried out under an inert gas atmosphere (since tris(dimethylamino) metal compound is sensitive to air) to reduce the influence of air on its purity. Then, the crude product of tris(dimethylamino) metal compound is subjected to gradient recrystallization in hexane solvent. By setting six temperature segments (10 °C, 0 °C, -10 °C, -20 °C, -30 °C, -40 °C) and crystallizing for 1 h at different temperature segments, the resulting product has fewer impurities. The reason is that if the product is directly recrystallized in an environment of -40 °C, the crystallization rate of the product will be too fast, resulting in the formation of impurity encapsulation, and the crystal form and purity of the product will be poor. Detailed Description of the Invention

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1

[0031] Preparation of lithium dimethylamide n-hexane suspension:

[0032] After evacuating and purging the A-50L dry reaction kettle with vacuum / nitrogen three times, it was placed under normal pressure nitrogen protection. With the outlet valve of the steel cylinder containing n-butyllithium closed, the nitrogen inlet valve was connected to the nitrogen pipe. After purging the air in the pipeline with vacuum / nitrogen, the nitrogen valve of the n-butyllithium steel cylinder was opened to replenish nitrogen to the steel cylinder until the pressure reached 0.1 MPa, and then the n-butyllithium nitrogen valve was closed and the nitrogen pipe was disconnected. Under nitrogen protection, the liquid outlet valve of the n-butyllithium steel cylinder was connected to the inlet valve of the A-50L preparation kettle using a stainless steel hose. The n-butyllithium steel cylinder was placed on a platform scale, and 8.80 kg (3.58 mol / kg, 31.48 mol) of n-butyllithium was weighed and added to the reaction kettle. The n-butyllithium in the pipeline was blown back into the n-butyllithium steel cylinder by nitrogen. After closing the valves of the n-butyllithium steel cylinder and the reaction kettle inlet valve, the valve of the n-butyllithium steel cylinder and the stainless steel feed hose were disconnected. The stainless steel feed hose was connected to the outlet valve of the n-hexane steel cylinder. The outlet valve of the n-hexane steel cylinder and the reaction kettle inlet valve were opened, and 20 kg of n-hexane was transferred into the reaction kettle by nitrogen pressure. Then the valves at both ends of the feed pipe were closed. Stirring was started and the rotation speed was controlled at 100 rpm. The n-hexane steel cylinder was disconnected from the feed hose. The dimethylamine steel cylinder was connected to the gas inlet of the A-50L reaction kettle using a stainless steel hose. The dimethylamine steel cylinder was placed on a platform scale and the scale reading was reset to zero. First, the gas inlet valve on the reaction kettle was opened, and then the dimethylamine steel cylinder valve was gradually opened. Dimethylamine was gradually added to the reaction kettle in gaseous form. The reaction temperature was controlled within the range of 20 °C, and the feeding time was 1.5 h. The feeding amount of dimethylamine gas was 1440 g (32.0 mol). After adding dimethylamine, stirring was continued for 1 hour within the range of 20 °C to obtain a suspension of lithium dimethylamide in n-hexane.

[0033] Example 2

[0034] Preparation of suspension of lithium dimethylamide in n-hexane:

[0035] After evacuating and purging the A-50L dry reactor with vacuum / nitrogen three times, it was placed under normal pressure nitrogen protection. With the outlet valve of the steel cylinder containing n-butyllithium closed, the nitrogen inlet valve was connected to the nitrogen pipe. After purging the air in the pipeline with vacuum / nitrogen, the nitrogen valve of the n-butyllithium steel cylinder was opened to replenish nitrogen to the steel cylinder until the pressure reached 0.1 MPa, then the n-butyllithium nitrogen valve was closed and the nitrogen pipe was disconnected. Under nitrogen protection, the liquid outlet valve of the n-butyllithium steel cylinder was connected to the inlet valve of the A-50L preparation kettle using a stainless steel hose. The n-butyllithium steel cylinder was placed on a floor scale, and 8.80 kg of n-butyllithium (3.58 mol / kg, 31.48 mol) was weighed and added to the reactor. The n-butyllithium in the pipeline was blown back into the n-butyllithium steel cylinder by nitrogen. After closing the n-butyllithium steel cylinder valve and the reactor inlet valve, the connection between the n-butyllithium steel cylinder valve and the stainless steel feed hose was disconnected. The stainless steel feed hose was connected to the outlet valve of the n-hexane steel cylinder. The outlet valve of the n-hexane steel cylinder and the reactor inlet valve were opened, and 20 kg of n-hexane was transferred into the reactor by nitrogen pressure. Then the valves at both ends of the feed pipe were closed. Stirring was started, and the rotation speed was controlled at 200 rpm. The n-hexane steel cylinder was disconnected from the feed hose. The dimethylamine steel cylinder was connected to the gas inlet of the A-50L reactor using a stainless steel hose. The dimethylamine steel cylinder was placed on a floor scale, and the floor scale reading was reset to zero. First, the gas inlet valve on the reactor was opened, and then the dimethylamine steel cylinder valve was gradually opened. Dimethylamine was gradually added to the reactor in gaseous form. The reaction temperature was controlled within the range of 60 °C, and the feeding time was 3 h. The feeding amount of dimethylamine gas was 1440 g (32.0 mol). After adding dimethylamine, stirring was continued for 1 hour within the range of 60 °C to obtain a suspension of lithium dimethylamide in n-hexane.

[0036] Example 3

[0037] A method for preparing high-purity tris(dimethylamino)gallium dimer, comprising the following steps:

[0038] The first step is to prepare a crude product of tris(dimethylamino)gallium dimer:

[0039] Step S11: After nitrogen displacement of a dry A-10L stainless steel bottle equipped with a solid feeding valve, a nitrogen valve, and a discharge valve with an inner extension pipe, 1680 g (9.54 mol) of gallium trichloride was added into the steel bottle under nitrogen protection. Then, 4 kg of toluene was added to form a toluene solution, and the solid feeding valve was closed. The discharge valve of the stainless steel bottle of the gallium trichloride solution was connected to the feed port of a A-50L reactor for preparing a lithium dimethylamide n-hexane suspension (containing 31.48 mol of lithium dimethylamide) in Example 1 through a stainless steel hose. The stirring of the reactor was started, the discharge valve of the gallium trichloride steel bottle was opened, and the feed valve of the A-50L reactor was slowly opened. The trimethylgallium toluene solution was slowly added into the A-50L reactor through nitrogen pressure. The feeding rate was controlled by controlling the opening degree of the discharge port valve of the gallium trichloride solution, thereby controlling the temperature in the reactor. The temperature of the reaction solution was controlled at 40-60 °C. After the addition was completed, stirring was continued at 60 °C for 3 h to obtain a crude product solution;

[0040] Step S12: Prepare a clean B-50L reactor, and purge it with nitrogen for 30 minutes to make the inside of the reactor in a normal-pressure nitrogen state. The clarified mother liquor obtained by filtering the crude product solution prepared in the A-50L reactor through a filter pipe was transferred into the B-50L reactor. The solvent in the product mother liquor was completely removed under reduced pressure at 60 °C to obtain a light brown solid, and a crude product of tris(dimethylamino)gallium dimer was obtained;

[0041] Second step: Purify the crude product of tris(dimethylamino)gallium dimer:

[0042] Under atmospheric pressure and nitrogen protection, 2.0 kg of crude tris(dimethylamino)gallium dimer was added into a B-50L reactor. 6 kg of dry n-hexane (water content < 60 ppm) was added. The stirring was slowly started and the reactor temperature was set at 60 °C. Stir for 1 h to completely dissolve the solid. A 10 L three-necked glass round-bottom flask was washed and dried, and valve interfaces were configured at the three bottle mouths respectively. One of the interfaces was connected to the nitrogen pipeline, and the other two ports were kept open. After purging the air in the flask with high-purity nitrogen for 30 minutes, the valves at the three bottle mouths were closed. One of the bottle mouth valves was used as the feed port and connected to the discharge port of the B-50L reactor through a tetrafluoro tube. The valve at the discharge port of the B-50L reactor and the third valve of the flask were opened for exhaust and pressure relief. The discharge valve of the B-50L reactor was slowly opened, and relying on the pressure difference between the reactor and the glass bottle, the n-hexane solution of the crude tris(dimethylamino)gallium dimer was transferred from the B-50L stainless steel reactor to the 10 L flask under nitrogen protection. The discharge valve of the B-50L, the exhaust valve of the glass bottle, and the feed valve were closed in sequence. The pipeline connected to the reactor was dissociated. With the three bottle mouths kept airtight, the 10 L glass bottle was placed in a cold bath equipped with a refrigeration compressor for stepwise cooling and crystallization. The refrigeration temperature of the cold bath was set at six temperature segments: 10 °C, 0 °C, -10 °C, -20 °C, -30 °C, and -40 °C in sequence; during the stepwise cooling crystallization process, when the temperature in the bath reached the first set temperature of 10 °C, it was maintained at this temperature for 60 minutes, then the set temperature was changed to the second set temperature of 0 °C, and it was also maintained at this temperature for 60 minutes before changing the refrigeration temperature to the next set temperature. And so on to complete the entire stepwise cooling crystallization process. During the crystallization process, a large amount of colorless crystalline products were observed to form in the glass bottle. After completing the entire cooling crystallization process, the nitrogen valve of the glass bottle was opened. Under nitrogen protection, the crystallization mother liquor was transferred to a waste liquid bucket as waste liquid using a tetrafluoro tube. The glass bottle was taken out of the cold bath, and 2.5 kg of n-hexane was added into the bottle under nitrogen protection. It was heated to 60 °C until the crystals were completely dissolved, and then cooled to room temperature for the second gradient cooling recrystallization process. The temperature setting for the gradient cooling recrystallization was exactly the same as that for the first recrystallization process. The crystalline solid product after separating the mother liquor was vacuum dried at room temperature for 3 h to obtain the tris(dimethylamino)gallium dimer product.

[0043] The tris(dimethylamino)gallium dimer product obtained in Example 3 was analyzed by ICP-OES and NMR. The purity of the tris(dimethylamino)gallium product was 99.9999% (6N).

[0044] Example 4

[0045] Compared with Example 3, the gallium trichloride in Example 3 was replaced with the same molar amount of gallium tribromide, the protective gas was replaced from nitrogen to argon, and the addition amount of the crude product of tris(dimethylamino)gallium dimer in the second step was adjusted to 2.2 kg. Other raw materials and steps were the same as in Example 3, and a tris(dimethylamino)gallium dimer product was obtained.

[0046] The tris(dimethylamino)gallium dimer product obtained in Example 4 was analyzed by ICP-OES and NMR. The purity of the tris(dimethylamino)gallium dimer product was 99.9999% (6N).

[0047] Example 5

[0048] A preparation method of high-purity tris(dimethylamino)indium dimer, comprising the following steps:

[0049] The first step, preparing the crude product of tris(dimethylamino)indium dimer:

[0050] Step S11: After nitrogen replacement of a dry A-10L stainless steel bottle equipped with a solid feeding valve, a nitrogen valve and an inner extension pipe discharging valve, 2797 g (9.54 mol) of indium trichloride was added into the steel bottle under nitrogen protection, and then 4 kg of toluene was added to form an indium trichloride toluene solution, and the solid feeding valve was closed. The discharging valve of the stainless steel bottle was connected to the feeding port of an A-50L reaction kettle for preparing a lithium dimethylamide n-hexane suspension (containing 31.48 mol of lithium dimethylamide) in Example 2 through a stainless steel hose. The stirring of the reaction kettle was started, the discharging valve of the steel bottle was opened, and the feeding valve of the A-50L reaction kettle was slowly opened. The indium trichloride toluene solution was slowly added into the A-50L reaction kettle through nitrogen pressure. The feeding speed was controlled by the opening degree of the discharging port valve to further control the temperature in the reaction kettle. The temperature of the reaction solution was controlled at 40 °C. After the addition was completed, stirring was continued at 40 °C for 3 h to obtain a crude product solution;

[0051] Step S12: Prepare a cleaned B-50L reaction kettle, and make the inside of the kettle in a normal-pressure nitrogen state through nitrogen purging for 30 minutes. The clarified mother liquor obtained by filtering the crude product solution prepared in the A-50L using a filtering pipeline was transferred into the B-50L reaction kettle. The solvent in the product mother liquor was completely removed under reduced pressure at 60 °C to obtain a light brown solid, and the crude product of tris(dimethylamino)indium dimer was obtained;

[0052] The second step, purifying 2.4 kg of the crude product of tris(dimethylamino)indium dimer by the stepwise cooling recrystallization method: The purification process was the same as in Example 3, only replacing the crude product of tris(dimethylamino)gallium dimer with the crude product of tris(dimethylamino)indium dimer, and the remaining steps remained unchanged, and a tris(dimethylamino)indium dimer product was obtained.

[0053] The obtained tris(dimethylamino)indium dimer product in Example 5 was analyzed by ICP-OES and NMR, and the purity of the tris(dimethylamino)indium dimer product was 99.9999% (6N).

[0054] Example 6

[0055] Compared with Example 5, indium trichloride in Example 5 was replaced with the same molar amount of indium tribromide, and the addition amount of the crude tris(dimethylamino)indium dimer in the second step was adjusted to 2.5 kg. Other raw materials and steps were the same as those in Example 5, and a tris(dimethylamino)indium dimer product was obtained.

[0056] The obtained tris(dimethylamino)indium dimer product in Example 6 was analyzed by ICP-OES and NMR, and the purity of the tris(dimethylamino)indium dimer product was 99.9999% (6N).

[0057] Example 7

[0058] A preparation method of high-purity tris(dimethylamino)aluminum dimer, comprising the following steps:

[0059] The first step, preparing the crude tris(dimethylamino)aluminum dimer:

[0060] Step S11: After nitrogen replacement of a dry A-10L stainless steel bottle equipped with a solid feeding valve, a nitrogen valve and an inner extension tube discharging valve, 1272 g (9.54 mol) of aluminum trichloride was added into the steel bottle under nitrogen protection, and then 4 kg of toluene was added to form an aluminum trichloride toluene solution, and the solid feeding valve was closed. The discharging valve of the stainless steel bottle was connected to the feeding port of a A-50L reaction kettle for preparing a lithium dimethylamide n-hexane suspension (containing 31.48 mol of lithium dimethylamide) in Example 1 through a stainless steel hose. The stirring of the reaction kettle was started, the discharging valve of the steel bottle was opened, and the feeding valve of the A-50L reaction kettle was slowly opened. The aluminum trichloride toluene solution was slowly added into the A-50L reaction kettle through nitrogen pressure. The feeding speed was controlled by the opening degree of the discharging port valve to control the temperature in the reaction kettle. The temperature of the reaction solution was controlled at 40 °C. After the addition was completed, stirring was continued at 40 °C for 3 h to obtain a crude product solution;

[0061] Step S12: Prepare a clean B-50L reaction kettle, and make the inside of the kettle in a normal-pressure nitrogen state by nitrogen purging for 30 minutes. The clarified mother liquor obtained by filtering the crude product solution prepared in the A-50L through a filtering pipeline was transferred into the B-50L reaction kettle. The solvent in the product mother liquor was completely removed under reduced pressure at 60 °C to obtain a light brown solid, and the crude tris(dimethylamino)aluminum dimer was obtained;

[0062] Step 2: Purify 1.6 kg of crude tris(dimethylamino)aluminum dimer by the stepwise cooling recrystallization method: The purification process is the same as that in Example 3, except that the crude tris(dimethylamino)gallium dimer is replaced with the crude tris(dimethylamino)aluminum dimer, and the other steps remain unchanged, to obtain the tris(dimethylamino)aluminum dimer product.

[0063] Perform ICP-OES and NMR analyses on the tris(dimethylamino)aluminum dimer product obtained in Example 7. The purity of the tris(dimethylamino)aluminum dimer product is 99.9999% (6N).

[0064] Example 8

[0065] Compared with Example 7, replace aluminum trichloride in Example 7 with the same molar amount of aluminum tribromide, and adjust the addition amount of the crude tris(dimethylamino)aluminum dimer in Step 2 to 1.7 kg. The other raw materials and steps are the same as those in Example 7 to obtain the tris(dimethylamino)aluminum dimer product.

[0066] Perform ICP-OES and NMR analyses on the tris(dimethylamino)aluminum dimer product obtained in Example 8. The purity of the tris(dimethylamino)aluminum dimer product is 99.9999% (6N).

[0067] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0068] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of high-purity gallium, indium, and aluminum amide compounds, characterized in that, It includes the following steps: The first step: Prepare a lithium dimethylamide n-hexane suspension; The second step: Prepare a crude product of tris(dimethylamino) metal compound; The third step: Purify the crude product of tris(dimethylamino) metal compound by stepwise cooling recrystallization to obtain high-purity amino gallium, indium, and aluminum compounds; Among them, the specific operation of purifying the crude product of tris(dimethylamino) metal compound by stepwise cooling recrystallization is as follows: Under an inert gas atmosphere, add the crude product of tris(dimethylamino) metal compound to the reaction kettle, first add n-hexane, stir at 60 °C for 1 h, then transfer it to a three-necked flask, and perform the first gradient cooling recrystallization. After completion, remove the crystallization mother liquor, take the three-necked flask out of the cold bath, add n-hexane to the three-necked flask again, heat up to 60 °C until all the crystals are dissolved, then cool down to room temperature, and perform gradient cooling recrystallization again. After completion, separate the mother liquor, and vacuum dry the crystallization product at room temperature for 3 h; The specific process of the first gradient cooling recrystallization is as follows: Seal the three-necked flask and place it in a cold bath. Set the refrigeration temperature of the cooling bath to 10 °C, 0 °C, -10 °C, -20 °C, -30 °C, and -40 °C in sequence, and treat each temperature section for 60 min; The operation steps of the second gradient cooling recrystallization are the same as those of the first gradient cooling recrystallization; The mass ratio of the crude product of tris(dimethylamino) metal compound, the first addition of n-hexane, and the second addition of n-hexane is 1.6 - 2.5:6:2.

5.

2. The preparation method of a high-purity amino gallium, indium, and aluminum compound according to claim 1, characterized in that, The n-hexane is dry n-hexane, and the moisture content of the dry n-hexane is less than 60 ppm.

3. The preparation method of a high-purity amino gallium, indium, and aluminum compound according to claim 1, characterized in that, The preparation steps of the lithium dimethylamide n-hexane suspension are as follows: Under an inert gas atmosphere, add n-butyllithium and n-hexane to the reaction kettle, and introduce dimethylamine while stirring. Control the reaction temperature at 20 - 60 °C. After the introduction of dimethylamine is completed, continue to stir and react at 20 - 60 °C for 1 h to obtain a lithium dimethylamide n-hexane suspension.

4. The preparation method of a high-purity gallium amide, indium amide, and aluminum compound according to claim 3, wherein, The dosage ratio of n-butyllithium, n-hexane, and dimethylamine is 31.48 mol:20 kg:32.0 mol.

5. A method for preparing a high-purity amino gallium, indium, and aluminum compound according to claim 1, characterized in that, The preparation steps of the crude product of tris(dimethylamino) metal compound are as follows: Under an inert gas atmosphere, while stirring, add a toluene solution of trihalide to the reaction kettle containing the lithium dimethylamide n-hexane suspension. Control the reaction temperature at 40 - 60 °C during the addition process. After the addition is completed, stir and react at 60 °C for 3 h to obtain a mother liquor. Filter the mother liquor, and remove the solvent from the filtrate under reduced pressure at 60 °C to obtain a crude product of tris(dimethylamino) metal compound.

6. The preparation method of a high-purity gallium, indium, and aluminum amino compound according to claim 5, wherein, The toluene solution of trihalide is composed of trihalide and toluene. The dosage ratio of trihalide, toluene, and lithium dimethylamide is 9.54 mol:4 kg:31.48 mol.

7. The preparation method of a high-purity amino gallium, indium, and aluminum compound according to claim 5, characterized in that, The trihalide is one of gallium trichloride, indium trichloride, aluminum trichloride, gallium tribromide, indium tribromide, and aluminum tribromide.