KR101149309B1 - Reaction chamber for gallium nitride and fabricating method for gallium nitride - Google Patents

Abstract

A gallium nitride growth reactor, wherein a gallium nitride growth reactor is provided with a gas shower block for generating a gas flow along an inner wall of the reactor separately from a reaction gas for producing gallium nitride. . In the case of growing gallium nitride by gas phase epitaxy, polycrystalline crystals are formed on the inner wall of the reactor by supplying a reaction gas into the gallium nitride growth reactor and forming a separate gas shower block along the inner wall of the reactor. It is possible to prevent the deposition of gallium nitride and to grow high quality gallium nitride without defects.

Gallium Nitride, Reactor, Shower Block

Description

Gallium nitride growth reactor and gallium nitride growth method {REACTION CHAMBER FOR GALLIUM NITRIDE AND FABRICATING METHOD FOR GALLIUM NITRIDE}

The present invention relates to a gallium nitride growth reactor and a gallium nitride growth method, and proposes a method of growing a high quality gallium nitride wafer by forming a gas shower block on the inner wall of the growth reactor so that reaction by-products do not accumulate on the inner wall. .

Gallium nitride is a semiconductor material having a bandgap energy of 3.39 eV and a direct transition type, and is useful for manufacturing light emitting devices in a short wavelength region. Because of the high nitrogen vapor pressure at the melting point, gallium nitride single crystal requires high temperature of 1500 ℃ or higher and 20000 atmosphere of nitrogen atmosphere, which makes it difficult to mass-produce it. Difficult to use

Until now, gallium nitride films have been grown on heterogeneous substrates by vapor phase growth methods such as metal organic chemical vapor deposition (MOCVD) or hydraulic vapor phase epitaxy (HVPE). The MOCVD method is difficult to use to obtain a GaN substrate of tens or hundreds of micrometers because the growth rate is too slow even though a high quality film can be obtained. For this reason, a growth method using HVPE is mainly used to obtain a GaN thick film.

A sapphire substrate is most commonly used as a dissimilar substrate for manufacturing a gallium nitride film because sapphire has a hexagonal structure such as gallium nitride, which is inexpensive and stable at high temperatures. However, sapphire causes strain at the interface due to gallium nitride and lattice constant difference (about 16%) and coefficient of thermal expansion (about 35%), which causes lattice defects and cracks in the crystals. It is difficult to grow a high quality gallium nitride film and shorten the life of the device fabricated on the gallium nitride film.

On the other hand, when gallium nitride is grown by using a gas phase epitaxy (HVPE) method, there is a problem in that polycrystalline gallium nitride (poly GaN) is deposited as a by-product of the reaction gas on the inner wall of the reactor.

The polycrystalline gallium nitride deposited on the inner wall of the reactor falls into unwanted particles on the surface of the gallium nitride wafer growing inside the reactor, causing surface defects on the gallium nitride wafer. It can lead to degradation.

In addition, polycrystalline gallium nitride that accumulates on the inner wall of the reactor during the growth of gallium nitride may cause cracks in the reactor when the reactor is cooled, thereby reducing the durability of the reactor and making it impossible to reuse quartz used as the inner wall material. There is this.

Accordingly, it is an object of the present invention to prevent the deposition of polycrystalline gallium nitride on the inner wall of the reactor during gallium nitride growth.

Another object of the present invention is to grow high quality gallium nitride without defects.

The present invention provides a gallium nitride growth reactor in which a gallium nitride growth reactor is provided with a gas shower block for generating a gas flow along an inner wall of the reactor, in addition to a reaction gas for producing gallium nitride. To provide.

The gas shower block supply unit is installed at the inlet of the reactor, and the gas shower block supply unit is separately installed from the reaction gas supply unit supplying the reaction gas.

The gas shower block may be a flow of N ₂ , Ar, or H ₂ gas, the gas flow rate of the gas shower block is preferably greater than the flow rate of the reaction gas.

The present invention also provides a method for growing gallium nitride by gas phase epitaxy, wherein a separate gas shower block is formed by a separate gas flow along the inner wall of the reactor along with supplying a reaction gas into the gallium nitride growth reactor. It provides a gallium nitride growth method characterized by growing gallium nitride while forming.

According to the present invention, it is possible to prevent the deposition of polycrystalline gallium nitride on the inner wall of the reactor during gallium nitride growth. In addition, it is possible to stably grow high quality gallium nitride without defects, thereby improving gallium nitride production yield and reducing the overall production cost.

When gallium nitride is grown by vapor phase epitaxy, gallium nitride (200) is supplied to a base substrate (not shown) on the support 210 by supplying a reaction gas in a growth reactor maintained at a high temperature as shown in FIG. Grow).

As a source for gallium nitride growth, for example, NH ₃ , HCl, and Ga metal may be used, and these reaction sources undergo two gas phase reactions in the reactor 100 as follows.

2HCl + 2Ga-> 2GaCl (gas) + H2

2GaCl + 2NH _3- > 2GaN + NH ₄ Cl + H2

In order to properly control this gas phase reaction, region I and region II are kept at different temperatures, and region II is maintained at about 900 ° C and region II is about 1100 ° C. As such, in order to maintain a high temperature, the inner wall 110 of the reactor is formed of a heat resistant material such as quartz, unlike the outer wall 105.

In the process of growing gallium nitride on the base substrate by a gas reaction, a gas flow that does not participate in the reaction or a second flow of polycrystalline gallium nitride that does not grow in a single crystal state may be deposited on the inner wall 110 of the reactor. .

Such polycrystalline gallium nitride deposition can reduce the durability of the reactor by causing a crack in the reactor when the temperature of the reactor changes due to the difference in the coefficient of thermal expansion with the quartz constituting the inner wall of the reactor. In addition, the polycrystalline gallium nitride deposited on the inner wall of the reactor may fall on the surface of the growing gallium nitride in the form of particles to reduce the quality of gallium nitride.

In the present invention, by forming a gas shower block of a different type from the reaction gas along the inner wall of the gallium nitride growth reactor, the above problems of the growth reactor during vapor phase epitaxy are fundamentally solved.

Referring to FIG. 2, in the reactor for growing gallium nitride, a gas shower block 310 for generating a gas flow along an inner wall of the reactor is formed separately from the reaction gas flow 300 for generating gallium nitride. You can see that.

The gas shower block 310 is controlled not to flow toward the inner center of the reactor by the gas flow flowing along the inner wall from the reactor inlet, and is discharged to the outside through a separate outlet 120 at the reactor outlet side.

This gas shower block blocks the reaction gas or reaction by-products supplied to the reactor during gallium nitride growth from the reactor inner wall. Therefore, no foreign matter, in particular polycrystalline gallium nitride, is deposited on the inner wall of the gallium nitride.

As a result, the quality characteristics of the grown gallium nitride film can be improved, and cracks do not occur in the inner wall even with frequent temperature changes in the reactor. In addition, it is possible to continuously recycle the quartz material of the inner wall of the reactor has a great effect on reducing the production cost.

3 shows a reactive gas supply unit 300a disposed at an inlet of a gallium nitride growth reactor and gas shower block supply units 310a and 310b forming a gas shower block. The gas shower block supply unit is preferably installed separately from the reaction gas supply unit for supplying the reaction gas.

The gas shower block supply unit may arrange a plurality of pipe-type supply pipes at the inlet of the reactor, but may also include a gas outlet 310c (see FIG. 4) having a flange structure including a plurality of holes 315. .

As the gas for forming the gas shower block, a gas which does not chemically react with the gallium nitride growth reaction gas, for example, N ₂ , Ar, or H ₂ gas may be used.

In the present invention, it is necessary to appropriately control the gas amount of the gas shower block in order to protect the inner wall of the reactor as compared with the flow of the reaction gas required for the growth of gallium nitride. For example, the gas amount of the gas shower block is preferably at least 25% or more as compared with the amount of the reaction gas.

In addition, it is very important to prevent foreign matters from accumulating on the inner wall of the gas flow rate reactor of the gas shower block so as not to prevent gallium nitride growth inside the reactor. In order to increase the foreign matter blocking effect of the gas shower block and not affect the gallium nitride reaction, as shown in FIG. 5, the gas flow rate V _f2 of the gas shower block is larger than the flow rate V _f1 of the reaction gas. It is preferable.

In the case of growing gallium nitride by gas phase epitaxy using such a reactor, gallium nitride is formed by supplying a reaction gas into the reactor and forming a gas shower block along the inner wall of the reactor. This can be grown stably.

The present invention has been exemplarily described through the preferred embodiments, but the present invention is not limited to such specific embodiments, and various forms within the scope of the technical idea presented in the present invention, specifically, the claims. May be modified, changed, or improved.

1 is a schematic diagram showing the formation of gallium nitride by the vapor phase epitaxy method.

Figure 2 is a schematic diagram showing a gas shower block of the gallium nitride reactor according to the present invention.

3 is a schematic diagram showing an example of a gas supply unit for forming a gas shower block.

Figure 4 is a perspective view showing a gas shower block supply in the form of a flange.

5 is a schematic view showing the gas flow rate in the reactor.

*** Explanation of symbols for the main parts of the drawing ***

100: reactor 105: outer wall

110: inner wall 200: gallium nitride

300: reaction gas flow 310: gas shower block

Claims (11)

In the reactor for growing gallium nitride, The interior is divided into two regions maintained at different temperatures, Apart from the reaction gas for producing gallium nitride, a gas shower block is formed along the inner wall of the reactor to generate a gas flow. The gas amount of the gas shower block is at least 25% compared to the amount of the reaction gas, and the gas flow rate of the gas shower block is relatively larger than the flow rate of the reaction gas, And a gas forming the gas shower block is discharged through an outlet formed separately from an outlet of the reactor for discharging the reaction gas to an outlet side of the reactor. The gallium nitride growth reactor of claim 1, wherein a gas shower block supply unit is installed at an inlet of the reactor. The gallium nitride growth reactor of claim 2, wherein the gas shower block supply unit is installed separately from the reaction gas supply unit supplying the reaction gas. The gallium nitride growth reactor of claim 2, wherein the gas shower block supply unit is formed in a flange structure including a plurality of holes. The gallium nitride growth reactor of claim 1, wherein the gas shower block is a flow of N ₂ , Ar, or H ₂ gas. delete delete delete In the method for growing gallium nitride by vapor phase epitaxy method, The inside of the gallium nitride growth reactor is divided into two regions and maintained at different temperatures, and a separate gas flow is provided along the inner wall of the reactor along with the supply of a reaction gas into the gallium nitride growth reactor. Grow gallium nitride while forming a gas shower block, The gas amount of the gas shower block is at least 25% compared to the amount of the reaction gas, and the gas flow rate of the gas shower block is relatively larger than the flow rate of the reaction gas, And a gas for forming the gas shower block through an outlet formed separately from an outlet of the reactor for discharging the reaction gas on an outlet side of the reactor. delete 10. The method of claim 9, wherein the gas shower block is a flow of N ₂ , Ar, or H ₂ gas.

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