KR100839757B1 - Method for producing gallium nitride crystal powder using exhaust gas removal system and apparatus for manufacturing same - Google Patents

Abstract

The present invention relates to a method for producing gallium nitride crystal powder and an apparatus for producing the same using an exhaust gas removal system. More specifically, the step of growing a crystalline powder of gallium nitride by mixing a gallium source and a mineralizer with a liquid ammonia solvent and nitriding under high temperature and high pressure; The present invention relates to a method for producing gallium nitride crystal powder using a flue gas removal system comprising removing a flue gas containing hydrogen gas generated in the reaction by using an adsorbent, and a manufacturing apparatus thereof.

According to the present invention, gallium nitride crystal powder which is commercially available and can realize mass production can be obtained in high yield.

Gallium nitride, GaN, light emitting device, electronic device

Description

Process for manufacturing gallium nitride crystal powder using exhaust gas removal system and apparatus for manufacturing same {Process and System for GaN Crystalline Powders Using Means for Removing Waste Gas}

1 is a cross-sectional view schematically showing an apparatus for producing gallium nitride crystal powder according to an embodiment of the present invention.

                     <Explanation of symbols for the main parts of the drawings>

1: Reaction vessel 2, 3: Cylinder type electric furnace

4: growth part 5: pressure gauge

6, 10: control valve 7, 11: pressure sealing adapter

8: gas outlet 9: guide tube

12 Ni-Al alloy powder 13 Cell for storage

The present invention relates to a method for producing gallium nitride crystal powder and an apparatus for producing the same using an exhaust gas removal system. In particular, the present invention relates to a method for producing gallium nitride crystal powder and apparatus for inhibiting the nitriding reaction of gallium nitride crystal powder and causing a low yield to be effectively removed.

Gallium nitride (GaN) is a direct-transition broadband semiconductor with a band gap of 3.39 eV, and is a useful material for short-wavelength light emitting devices and high temperature electronic devices. The growth of gallium nitride thin film and the device development using the same has been recognized for a long time, but the development has been delayed because it is difficult to grow high quality gallium nitride thin film.

In order to grow high quality GaN thin film, a GaN single crystal substrate is required. Currently, a GaN single crystal substrate having a usable size and quality is not mass-produced. Thus, heterogeneous substrates such as sapphire or SiC are used. Currently, representative mass-produced semiconductor single crystal substrates are Si or GaAs, which are grown into large ingot single crystals by solution growth and melt growth, and then cut and polished. It is manufactured in the form of a wafer through a process. In the case of GaN single crystal substrates, a similar method has been developed to grow large ingots of single crystals. For this purpose, GaN powder is required as a starting material, and in particular, a large amount of high quality crystal powder is synthesized. It should be possible.

Conventionally, the dark heat synthesis method (Ammonothermalysis) is known as a method for synthesizing GaN crystals. The dark thermal synthesis method is a technique for synthesizing GaN crystals by nitriding metal Ga in supercritical ammonia formed by charging metal Ga and liquid ammonia in a reaction vessel and then heating it.

In addition, Korean Patent No. 493768 discloses crystallization of gallium nitride from gallium nitride crystal nuclei through a crystal nucleation step of generating crystal nuclei from gallium nitride and a chemical reaction between gallium halide and ammonia gas on the crystal nuclei of gallium nitride. Disclosed is a method and apparatus for producing gallium nitride powder, comprising a powder growth step of growing gallium nitride powder to form gallium nitride powder.

The synthesis of these GaN crystal powders is usually performed in a hydrogen atmosphere. Accordingly, the finished GaN crystal powder or polycrystal contains a large amount of hydrogen atoms. These hydrogen atoms are included in the crystal to promote decomposition of the nitride compound, or as the nitriding reaction of the metal Ga proceeds, hydrogen generated by decomposition from ammonia is continuously accumulated in the container to inhibit the nitriding reaction of Ga. Therefore, there is a problem that the overall yield of gallium nitride crystal powder is low and not suitable for commercially available mass production.

Accordingly, an object of the present invention is to provide a method for producing gallium nitride crystal powder using a flue gas removal system containing hydrogen gas that can facilitate the nitriding reaction and can be commercially available and can be mass-produced. .

Method for producing a gallium nitride crystal powder according to the present invention for achieving the above technical problem,

(a) mixing a gallium source and a mineralizer with a liquid ammonia solvent and nitriding under high temperature and high pressure to grow a crystalline powder of gallium nitride;

(b) removing the exhaust gas generated in the reaction by using an adsorbent.

Here, the gallium source is preferably a metal gallium or gallium halide as a raw material, the mineralizer is preferably selected from one or more selected from the group consisting of ammonium halide, alkali amide, and alkali azide. At this time, the reaction temperature of the nitriding reaction is 400 to 500 ℃, the reaction pressure is preferably 1,000 to 2,000 atm.

In addition, the exhaust gas is preferably removed by using an adsorbent containing Ni-Al alloy powder, in which case the mixing ratio is preferably in the range of 50 to 100 parts by weight of Al powder with respect to 100 parts by weight of Ni powder.

In addition, it is preferable that the average particle diameter of the final gallium nitride crystal powder is a powder of 0.01 to 10 ㎛.

On the other hand, the apparatus for producing gallium nitride crystal powder according to the present invention for achieving the above technical problem more effectively, a crystal powder made of gallium nitride by mixing a gallium source and a mineralizer with a liquid ammonia solvent and nitriding under high temperature and high pressure Crystal growth means for growing the lysate; And means for removing exhaust gas comprising hydrogen gas exhausted from the crystal growth means, wherein the exhaust gas removing means is configured to be installed independently of the crystal generating means.

Here, the exhaust gas removing means, the guide tube for guiding the exhaust gas containing hydrogen gas generated by the crystal growth means; A control valve provided on the guide pipe to control the inflow of the gas; It is provided in communication with the guide tube and comprises a storage cell for receiving an adsorbent for adsorbing the exhaust gas introduced by the control valve. At this time, the exhaust gas adsorbent is preferably made of Ni-Al alloy powder.

The exhaust gas removing apparatus for producing a gallium nitride crystal powder according to the present invention for achieving the above technical problem is detachably coupled to crystal growth means for growing a crystal powder made of gallium nitride hydrogen discharged from the crystal growth means And a storage cell containing an adsorbent for adsorbing exhaust gas containing gas.

The apparatus may further include connecting means for connecting the storage cell and the crystal growth means.

Here, the connecting means is one side is connected to the crystal growth means and the other side is connected to the storage cell, the guide tube for guiding the exhaust gas containing hydrogen gas generated in the crystal growth means to the storage cell; It is preferable to include a control valve provided on the guide pipe to control the inflow of the exhaust gas into the storage cell.

In addition, the storage cell may further include a pressure sealing adapter provided in the storage cell to be detachable to the guide tube. Here, as the pressure sealing adapter is provided in the storage cell containing the adsorbent, the storage cell is provided in the form of a high-pressure cell, so that the storage cell is easily detached from the guide tube connected to the crystal growth means. You can.

Hereinafter, the present invention will be described in detail.

The method for producing gallium nitride crystal powder of the present invention comprises (a) a gallium nitride crystal powder growth step; (b) exhaust gas removal step using adsorbent.

Preferably, the gallium nitride crystal powder growth step and the exhaust gas removal step are performed in individual reactors installed independently, and the exhaust gas removal step is preferably continued in time from the gallium nitride crystal powder growth step.

Crystallized gallium nitride (GaN) grown by the growth process of the gallium nitride crystal powder according to step (a) includes crystallizing or precipitating the gallium nitride feed source or its starting material with crystalline gallium nitride.

More specifically, the growth process of the gallium nitride crystal powder is performed under high temperature and high pressure (HTHP) conditions with a supercritical fluid solvent such as liquid ammonia in a reactor provided with a gallium feed source and a mineralizer.

The supercritical fluid refers to a rich gas that maintains above a critical temperature, which is a temperature at which gas cannot be liquefied by pressure. Supercritical fluids have a lower viscosity and easier diffusion than liquids, but have similar solvation capabilities as liquids.

The gallium feed source is not particularly limited, but may be metal gallium, and gallium halide. Further, the mineralizer is not particularly limited, but is ammonium halide selected from NH ₄ F, NH ₄ Cl NH ₄ I, and the like; Alkali amides selected from LiNH ₂ , NaNH ₂ , KNH ₂ and the like; And alkali azide selected from LiN ₃ , NaN ₃ , KN ₃ , and the like. At this time, the preferred reaction temperature for the growth of the gallium nitride crystal powder is 400 to 500 ℃, the reaction pressure is 1,000 to 2,000 atm.

As can be seen from Schemes 1 and 2, when gallium is used as the gallium source, or when gallium halide is used, hydrogen gas and hydrogen chloride gas are generated. These gases act as a factor in raising the pressure in the reactor, causing surface defects of the grown gallium nitride crystal powder. Hydrogen chloride also clogs the exhaust pipe by depositing a chloride compound on the side of the exhaust pipe.

2Ga + 2NH ₃ → 2GaN + 3H ₂ ↑

GaCl + NH ₃ → GaN + HCl ↑ + H ₂ ↑

GaCl ₃ + NH ₃ → GaN + 3HCl ↑

Accordingly, the exhaust gas that inhibits the growth and yield of the crystal powder should be removed. In the step (b), hydrogen gas can be effectively removed. In addition, hydrogen chloride gas may be further removed.

The exhaust gas removal step (b) is performed in a separate reactor installed independently of the gallium nitride crystal powder growth step (a), and is performed continuously in time from the gallium nitride crystal powder growth step.

The exhaust gas removal adsorbent is not particularly limited, but may be used in the form of a powder of metal group M (M = Mn, Fe, Co. Ni, Cu) having excellent hydrogen adsorption properties or a mixture powder of two or more kinds selected and combined. Can be. It can also be used as M-Al alloy powder, M-Al-La alloy powder, M-La alloy powder made by mixing the single powder or mixed powder with other metals. Here, instead of Al, Ga, Mg, Ca, or a combination thereof may be selected and used instead of La, Ce or a combination thereof. Herein, the M-Al-based, M-Al-La-based and M-La-based alloy powders are preferably blended in an amount of 50 to 100 parts by weight based on Al, Al-La and La based on 100 parts by weight of M-.

Among the above materials, an exhaust gas adsorbent containing Ni-Al alloy powder is preferably used. The mixing ratio of the Ni-Al alloy powder which can effectively adsorb and remove the exhaust gas is that the Al powder is blended in an amount of 50 to 100 parts by weight based on 100 parts by weight of Ni powder.

Optionally, further heat treatment of the obtained gallium nitride crystal powder in a nitrogen atmosphere at a temperature of 600 ° C. or higher, preferably 700 to 900 ° C., may remove hydrogen that may remain in a small amount in the synthesized gallium nitride crystal powder. In addition, trace mineralizers that may be incorporated into the gallium nitride powder during the collection process after the reaction is completed, ammonia adsorbed to the gallium nitride powder, and Ga remaining unreacted during dark thermal synthesis are generated due to reaction with moisture in the air. It can effectively remove even Ga-based hydroxides.

According to the manufacturing method of the gallium nitride crystal powder of the present invention, since the gallium nitride crystal powder generation step and the exhaust gas removal step is carried out continuously for a time, the overall manufacturing time can be much shorter, mass production of defect free crystal powder in high yield can do.

On the other hand, the apparatus for producing gallium nitride crystal powder embodied according to the production method of the present invention, a crystal growth in which a gallium source and a mineralizer are mixed with a liquid ammonia solvent and nitrided under high temperature and high pressure to grow crystal powder made of gallium nitride Way; And means for removing an exhaust gas containing hydrogen gas exhausted from the crystal growth means.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment suitable for the manufacturing apparatus of the gallium nitride crystal powder by this invention is described with drawing.

1 is a schematic cross-sectional view of a manufacturing apparatus for obtaining gallium nitride crystal fine powder having a size of 0.01 to 10 μm according to an embodiment suitable for the present invention.

Herein, the crystal growth means is not particularly limited, and a conventional gallium nitride crystal powder growth apparatus can be used.

As a preferable configuration of the device for crystal growth, a reaction vessel (1) having a growth portion (4) in which gallium nitride crystal powder is grown therein as shown in Fig. 1; Cylindrical electric furnaces (2,3) surrounding the outer circumferential surface of the reaction vessel (1); An adapter (7) for pressure sealing to enable the detachment of the reaction vessel; A control valve (6) for controlling the gas exhausted from the reaction vessel (1); It is configured to include a pressure gauge (5) for displaying the internal pressure of the reaction vessel (1).

In addition, as a preferred configuration of the exhaust gas removing means, as shown in Figure 1, provided on one side of the control valve 6 of the apparatus for growing crystalline powder, hydrogen gas generated from the reaction vessel (1) A guide pipe 9 for guiding the exhaust gas including; A control valve 10 provided on the guide pipe to control the inflow of the exhaust gas; A storage cell (13) provided in communication with the guide tube (9) and accommodating Ni-Al alloy powder (12) into which the exhaust gas introduced by the control valve (10) is adsorbed; It is configured to include a pressure sealing adapter (11) to enable the detachment of the storage cell (13).

Hereinafter, an operation process of the apparatus for producing gallium nitride crystal powder of the present invention having the above configuration will be described with reference to the drawings.

Referring to FIG. 1, the reaction vessel 1 is placed on the inner circumferential surfaces of the cylindrical electric furnaces 2 and 3, and gallium metal, mineralizer, and liquid ammonia are contained in the reaction vessel 1. An upper portion of the reaction vessel 1 uses a stainless steel pressure sealing adapter 7 provided with a liquid inlet tube (not shown) and a gas outlet 8 to block the inside of the reaction vessel 1 from air. The pressure inside the reaction vessel 1 is read by a pressure meter 5 running towards the gas outlet 8. Next, after removing the moisture and air in the reaction vessel (1) using a vacuum pump (not shown), to maintain a degree of vacuum of about 1,000 to 2,000 atm. Close the valve (not shown) connected to the vacuum pump, and gradually increase the temperature of the electric furnaces (2, 3) to increase the temperature of the growth section (4) on which gallium metal, mineralizer and liquid ammonia are placed. To be As liquid ammonia reacts with gallium metal, the following reactions occur:

2Ga + 2NH ₃ → 2GaN + 3H ₂ ↑

The generated hydrogen gas is provided on the guide tube through a control valve 6 for controlling the exhaust of the hydrogen gas and a guide tube 9 for guiding the generated hydrogen gas. 10) and a storage cell 13 provided in communication with the guide tube 9 and accommodating the Ni-Al alloy powder 12 into which the hydrogen gas introduced by the control valve 10 is adsorbed. It is adsorbed and removed by the Ni-Al powder-containing adsorbent.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the following examples are only intended to illustrate the best preferred embodiment to aid the understanding of the present invention is not limited or limited to the following examples of course.

<Examples 1-4>

After the Ga metal (5, 10, 15, 20 g) and 1 g of NH ₄ I powder were put into the reaction container 1 having an internal volume of 100 cc, the reaction container 1 was sealed. After the reaction vessel 1 was connected to a vacuum pump (not shown) to remove moisture and air in the reaction vessel 1, the reaction vessel 1 was filled with 50 g of liquid ammonia.

After storing 30 g of Ni-Al alloy powders 12 in a storage cell 13 having a volume of 10 cc, the storage cell 13 was sealed. After the storage cell 13 is connected to a vacuum pump (not shown) to remove moisture and air in the cell, the guide tube 9 is maintained while the reaction vessel 1 and the storage cell 13 are respectively sealed. ) Is connected. The reaction vessel 1 was heated to 500 ° C., and the pressure was increased to 1,000 atm, and the top valve 6 of the reaction vessel 1 and the top valve 10 of the storage cell 13 were opened and left for 3 days. . After the reaction vessel 1 is cooled to room temperature, the hydrogen gas and residual liquid ammonia generated from the nitriding reaction are evacuated, and the storage cell 13 is separated from the reaction vessel 1, and then the reaction vessel 1 is removed. Opened. After the contents of the reaction vessel (1) were received, the insolubles were filtered and washed with water to obtain an off-white or pale yellow GaN powder.

<Comparative Example 1-4>

Grayish white or pale yellow GaN powder was obtained in the same manner as in Example 1 except that the hydrogen gas removing unit according to Examples 1 to 4 was not separately provided.

<Evaluation>

In Examples 1-4 and Comparative Examples 1-4, the residual pressure according to the amount of metal Ga filling, and the yield of GaN powder according to it were compared. The results are summarized in Table 1 below.

Ga charge amount 5 g [residual pressure (atm) / yield (g)] 10 g [residual pressure (atm) / yield (g)] 15 g [Residual Pressure (atm) / Yield (g)] 20 g [residual pressure (atm) / yield (g)] Example 1-4 42 73 127 155 45 38 26 22 Comparative Example 1-4 10 14 38 77 63 62 44 38

As can be seen from the results of Table 1, it can be seen that Examples 1 to 4 compared to Comparative Examples 1 to 4, the residual pressure for each metal Ga filling amount was greatly reduced. In Examples 1 to 4 using the Ni-Al alloy powder, it is shown that the hydrogen gas in the reaction vessel 1 moves to the storage cell 13 and is adsorbed by the Ni-Al alloy powder to be effectively removed. Accordingly, when the amount of Ga charged is large, the amount of Ni-Al alloy powder can be sufficiently increased to completely remove the hydrogen gas.

By the hydrogen gas removal effect of the Ni-Al alloy powder, it was found that the yield of the GaN powder was improved by about two times or more with respect to the amount of metal Ga charged as compared with Comparative Examples 1 to 4.

On the other hand, according to Comparative Examples 1 to 4, due to the continuous accumulation of hydrogen gas generated as a result of the reaction between metal Ga and supercritical ammonia at high temperature and high pressure, considerable pressure remains in the reaction vessel even at room temperature after completion of the reaction. It can be seen that. In addition, it can be seen that such a residual pressure increases in proportion to the amount of metal Ga charged. The generation and accumulation of hydrogen gas is expected to have an undesirable effect of inhibiting the nitriding reaction of metal Ga, and the yield of actually obtained GaN powder tends to decrease with increasing residual pressure.

As described above, according to the manufacturing method and apparatus of the gallium nitride crystal powder of the present invention, by effectively removing the exhaust gas containing hydrogen gas generated during the nitriding reaction of gallium, the surface defects of the gallium nitride crystal powder can be caused. It is possible to prevent the pressure increase inside the reactor by the exhaust gas containing the hydrogen gas. Accordingly, the gallium nitride powder can be obtained in a yield more than twice that of the related art by a simple and economical process.

Claims (15)

(a) mixing a gallium source and a mineralizer with a liquid ammonia solvent and nitriding under a reaction temperature of 400 to 500 ° C. and a reaction pressure of 1,000 to 2,000 atm to grow a crystalline powder made of gallium nitride; And (b) removing the exhaust gas containing hydrogen gas generated in the reaction by using an adsorbent; Gallium nitride crystal powder manufacturing method comprising a. delete The method of claim 1, The gallium nitride crystal powder manufacturing method, wherein the gallium source is metal gallium, or gallium halide. The method of claim 1, The mineralizer is a gallium nitride crystal powder manufacturing method selected from the group consisting of ammonium halide, alkali amide, and alkali azide. The method of claim 1, The adsorbent Any one single powder selected from the group A consisting of Mn powder, Fe powder, Co powder, Ni powder and Cu powder; A first alloy powder in which any powder selected from the group B consisting of Al powder, Ga powder, Mg powder, and Ca powder is mixed with any powder selected from the group A; A second alloy powder obtained by mixing any powder selected from the C group consisting of La and Ce and any powder selected from the A group; A third alloy powder obtained by mixing any powder selected from the A group, any powder selected from the B group, and any powder selected from the C group; Gallium nitride crystal powder production method selected from. The method of claim 5, 50 to 100 parts by weight of any powder selected from the group B is added to 100 parts by weight of any powder selected from the group A in the first alloy powder, 50 to 100 parts by weight of any powder selected from the group C is blended with respect to 100 parts by weight of any powder selected from the group A in the second alloy powder, 50 to 100 parts by weight of a mixed powder obtained by mixing any powder selected from the group B and any powder selected from the group C with respect to 100 parts by weight of any powder selected from the group A in the third alloy powder Phosphorus gallium nitride crystal powder manufacturing method. The method of claim 1, The gallium nitride crystal powder manufacturing method further comprises the step of heat-treating in a nitrogen atmosphere, the gallium nitride crystal powder at a temperature of 600 ~ 900 ℃. A gallium nitride crystal prepared according to any one of claims 1 and 3 to 7, which is in the form of a powder having an average particle diameter of 0.01 to 10 µm. Crystal growth means for growing a crystalline powder made of gallium nitride by mixing a gallium source and a mineralizer with a liquid ammonia solvent and nitriding under a reaction temperature of 400 to 500 ° C. and a reaction pressure of 1,000 to 2,000 atm; And Means for removing exhaust gas containing hydrogen gas exhausted from said crystal growth means It is configured to include, wherein the exhaust gas removing means is a device for producing gallium nitride crystal powder is provided independently from the crystal generating means. The method of claim 9, A guide tube for guiding the exhaust gas containing hydrogen gas generated by the crystal growth means, wherein the exhaust gas removing means is provided; A control valve provided on the guide pipe to control the inflow of exhaust gas; Apparatus for producing gallium nitride crystal powder is provided in communication with the guide tube and comprises a storage cell for containing an adsorbent for adsorbing the exhaust gas introduced by the control valve. The method of claim 10, The adsorbent Any one single powder selected from the group A consisting of Mn powder, Fe powder, Co powder, Ni powder and Cu powder; A first alloy powder in which any powder selected from the group B consisting of Al powder, Ga powder, Mg powder, and Ca powder is mixed with any powder selected from the group A; A second alloy powder obtained by mixing any powder selected from the C group consisting of La and Ce and any powder selected from the A group; A third alloy powder obtained by mixing any powder selected from the A group, any powder selected from the B group, and any powder selected from the C group; An apparatus for producing gallium nitride crystal powder selected from among them. Preparation of gallium nitride crystal powder comprising a storage cell removably coupled to crystal growth means for growing crystal powder made of gallium nitride and containing an adsorbent for adsorbing exhaust gas containing hydrogen gas exhausted from the crystal growth means Exhaust gas removal device for the device. The method of claim 12, The apparatus for producing exhaust gas of the gallium nitride crystal powder further comprising connecting means for connecting the storage cell and the crystal growth means. The method of claim 13, The connecting means A guide tube having one side connected to the crystal growth means and the other side connected to the storage cell to guide the exhaust gas containing hydrogen gas generated from the crystal growth means to the storage cell; And a control valve provided on the guide tube to control the inflow of the exhaust gas into the storage cell. The method of claim 14, And a pressure sealing adapter provided in the storage cell such that the storage cell is detachable from the guide tube.

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