KR20130000294A - Apparatus for fabricating ingot - Google Patents

Abstract

PURPOSE: An apparatus for manufacturing ingot is provided to quickly supply much amount of source gas including carbon and silicon etc to a chamber and to rapidly grow ingot. CONSTITUTION: A crucible(30) includes a raw material. The raw material is vaporized by arc discharging. The raw material includes carbon, and silicon or silicon carbide. A first electrode(40) is positioned in the lower part of the crucible. A second electrode(50) is positioned in the upper part of the crucible. A seed holder(80) fixes a seed crystal.

Description

Ingot manufacturing equipment {APPARATUS FOR FABRICATING INGOT}

The present description relates to an ingot manufacturing apparatus.

In general, the importance of the material in the electrical, electronics industry and mechanical parts field is very high, which is an important factor in determining the characteristics and performance index of the actual final component.

Si, which is used as a representative semiconductor device material, is vulnerable to temperatures of more than 100 degrees Celsius, causing frequent malfunctions and failures, and thus requires various cooling devices. As Si shows such physical limitations, broadband semiconductor materials such as SiC, GaN, AlN, and ZnO are in the spotlight as next-generation semiconductor device materials.

Here, compared to GaN, AlN and ZnO, SiC is excellent in thermal stability and excellent in oxidation resistance. In addition, SiC has an excellent thermal conductivity of about 4.6W / Cm ℃, has the advantage that can be produced as a large diameter substrate of 2 inches or more in diameter. In particular, SiC single crystal growth technology is most stably secured in reality, and industrial production technology is at the forefront as a substrate.

However, in order to grow from the stoichiometric solution, the SiC single crystal requires a pressure of 100,000 atm or more and a temperature of 3,200 ° C. or more which is thermodynamically similar to that of diamond. Therefore, single crystals are mainly manufactured by industrially using PVT (Physical Vapor Transport) method, that is, seed growth growth sublimation method, which mainly uses sublimation. At this time, in order to sublimate the raw material, it is common to sublimate according to the temperature gradient inside the crucible using induction heating using a coil.

An embodiment is an ingot manufacturing apparatus capable of rapid growth using an electric arc.

Ingot manufacturing apparatus according to the embodiment, a crucible containing a raw material; A first electrode located below the crucible; A second electrode located above the crucible; And a seed crystal holder for fixing the seed crystal, wherein an arc discharge is generated between the first electrode and the second electrode.

The raw material may be vaporized by a heat source generated in the arc discharge.

The raw material may include a carbon source, a silicon source or silicon carbide.

The second electrode may include graphite.

The first electrode may be composed of a plurality of electrodes.

The ingot manufacturing apparatus may further include a vacuum part.

The ingot manufacturing apparatus may further include a supply unit.

The ingot manufacturing apparatus can grow a silicon carbide single crystal.

According to the embodiment, it is possible to provide a novel method and apparatus for single crystal growth, for example SiC single crystal growth. Ingot manufacturing apparatus according to the embodiment may generate a high temperature of 3600 ℃ or more by the arc discharge generated by the first electrode and the second electrode including the first electrode and the second electrode, silicon source, carbon source or The rapid supply of silicon carbide sources can increase the growth rate of silicon carbide single crystals.

That is, as compared with using induction heating, source gases, such as carbon source and silicon source, can be supplied quickly and in large amounts into the reactor, thereby enabling rapid ingot growth.

1 is a schematic view of an ingot manufacturing apparatus according to an embodiment.
2 is a process chart of ingot production according to the embodiment.

In the description of embodiments, each layer, region, pattern, or structure may be “on” or “under” the substrate, each layer, region, pad, or pattern. Substrate formed in ”includes all formed directly or through another layer. Criteria for the top / bottom or bottom / bottom of each layer will be described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

With reference to FIG. 1, the ingot manufacturing apparatus which concerns on a 1st Example is demonstrated in detail. 1 is a cross-sectional view of the ingot production device according to the first embodiment.

Referring to FIG. 1, the ingot manufacturing apparatus according to the first embodiment includes a chamber 10, a crucible 30, an upper lid 20, a seed crystal holder 80, a guide member 90, and a vacuum part. line 60, a filling line 70, a first electrode 40, and a second electrode 50.

The crucible 30 may accommodate a raw material. The raw material may include a silicon source and a carbon source. More specifically, the raw material may include a mixture of coke and silicon powder (Si powder) or silicon carbide powder (SiC powder). The raw material accommodated in the crucible 30 may contain a mixture of coke and silicon powder or silicon carbide powder.

The crucible 30 may have a cylindrical shape to accommodate the raw material.

The crucible 30 may include a material having a melting point equal to or higher than the sublimation temperature of silicon carbide.

For example, the crucible 30 may be made of graphite.

In addition, the crucible 30 may be coated with graphite a material having a melting point equal to or higher than the sublimation temperature of silicon carbide. Here, it is preferable to use a material chemically inert to silicon and hydrogen at the temperature at which the silicon carbide single crystal is grown as the material to be applied on the graphite material. For example, metal carbide or metal nitride may be used. In particular, a mixture comprising at least two or more of Ta, Hf, Nb, Zr, W and V and a carbide comprising carbon may be applied. In addition, a mixture comprising at least two or more of Ta, Hf, Nb, Zr, W and V and a nitride comprising nitrogen may be applied.

The upper cover 20 may be located on the top of the crucible 30. The upper cover 20 may seal the crucible 30. The upper cover 20 may be sealed to allow a reaction to occur in the crucible 30. The seed crystal is located at the lower end of the upper cover. The seed crystal may be fixed by the seed crystal holder 80. The seed crystal holder 80 may include high density graphite.

The seed crystal is attached to the seed crystal holder 80. By attaching the seed crystals to the seed crystal holder 80, it is possible to prevent the grown single crystal from growing up to the upper cover 20. However, embodiments are not limited thereto, and the seed crystal may be directly attached to the upper cover 20.

The guide member 90 is located inside the crucible 30. The guide member 90 may be located at a portion where a single crystal grows. The guide member 90 may narrow the movement path of the sublimated silicon carbide gas to focus diffusion of the sublimed silicon carbide into the seed crystal. This can increase the growth rate of single crystals.

Subsequently, an insulator (not shown in the figure) may surround the crucible 30. The heat insulator maintains the temperature of the crucible 30 at a crystal growth temperature. Since the crystal growth temperature of silicon carbide is very high, graphite felt can be used. Specifically, the heat insulating material may be a graphite felt made of a cylindrical having a predetermined thickness by compressing the graphite fiber. In addition, the heat insulating material may be formed of a plurality of layers to surround the crucible 30.

The vacuum part 60 is positioned above the upper cover 20. The vacuum part 60 may be positioned to penetrate the upper cover 20. The vacuum unit 60 discharges gas or reaction by-products remaining inside by the reaction. Specifically, when the upper cover 20 is opened after the single crystal growth is completed, the inside may be exposed to air. In this case, air may be discharged through the vacuum unit 60, and unreacted silicon or carbon gas may also be discharged through the vacuum unit 60.

The supply unit 70 is located on the side of the heat insulator. The supply unit 70 may supply an inert gas such as argon or an auxiliary carbon source or a doping gas after the vacuum is formed.

The first electrode 40 is located below the crucible 30, and the second electrode 50 is located above the crucible 30. The second electrode 50 may be moved up and down and left and right by the driving unit 51 disposed outside the chamber.

Arc discharge occurs when constant electricity is applied to the first electrode 40 and the second electrode 50. Then, a high temperature of 3600 ° C. or more may occur in a predetermined region between the first electrode 40 and the second electrode 50 by arc discharge. One or more first electrodes 40 may be disposed in order to uniformly transfer an arc to the raw material inside the crucible. The second electrode 50 may be made of graphite to compensate for the lack of a carbon source during the reaction, and may supplement the carbon during the reaction.

2 illustrates a single crystal growth process by arc discharge of the first electrode 40 and the second electrode 50 according to the present embodiment.

Referring to FIG. 2, the single crystal growth process according to the present embodiment may include generating an arc discharge between the first electrode 40 and the second electrode 50; Vaporizing the raw material; And depositing the vaporized silicon carbide on seed crystals to grow a silicon carbide ingot.

The crucible 30 may include high purity silicon powder, which is a silicon source, and high purity coke, which is a carbon source, as a raw material. Alternatively, the crucible 30 may include silicon carbide powder. The crucible 30 was made of graphite. The second electrode 50 may be made of high purity graphite to compensate for the lack of a carbon source.

Constant electricity is applied to the first electrode 40 located below the crucible 30 and the second electrode 50 located above the crucible 30. At this time, electricity may be applied at an alternating voltage of 380V. Arc discharge occurs when constant electricity is applied to the first electrode 40 and the second electrode 50. Due to the arc discharge, a predetermined region between the first electrode 40 and the second electrode 50 may be a high temperature of 3600 ° C. or more, and the remaining areas may be maintained at a temperature in the range of 1500 ° C. to 2600 ° C. .

The first electrode 40 and the second electrode 50 generate a heat source by arc discharge. The raw material may be vaporized by heating the raw material with a heat source generated by the arc discharge. The heat source by the arc discharge may be a high temperature of 3600 ℃ or more. Preferably, it may occur above the vaporization temperature of the raw material.

The raw material accommodated in the crucible 30 is vaporized using the high temperature by the said arc discharge as a heat source. For example, sublimation of the silicon source and carbon source or silicon carbide occurs. In this case, in order to uniformly transfer the heat source to the raw material, the plurality of second electrodes 50 may be provided. By including a plurality of the second electrode 50, a uniform heat source can be transferred to the raw material, thereby smoothing ingot growth.

Due to the arc discharge, the temperature inside the crucible 30 may occur at a high temperature of 3600 ° C. or more.

Silicon carbide ingot growth by sublimation recrystallization of the raw material by the arc discharge is as follows.

The crucible 30 contains a carbon source and a silicon source, and the second electrode 50 may be made of graphite.

First, a certain amount of electricity is applied to the first electrode 40 and the second electrode 50 spaced apart from each other at a constant distance to generate an arc discharge. The arc discharge is continued such that the temperature inside the crucible 30 is equal to or higher than the melting temperature of the silicon (about 1500 ° C.). Preferably, the arc discharge can be continued until the temperature inside the crucible 30 due to the arc discharge becomes 2000 ° C to 2600 ° C. Silicon and carbon which are raw materials contained in the crucible 30 are vaporized by using the heat source by the arc discharge.

A temperature gradient must then be formed inside the crucible 30 to recrystallize the sublimed silicon and carbon, preferably silicon carbide. The recrystallization may be generated by a heat insulating material surrounding the crucible 30 and a duration of arc discharge by the first electrode 40 and the second electrode 50.

First, the arc discharge is continued to be equal to or higher than the sublimation temperature of the silicon source, and the fuel is vaporized. Then, the arc discharge is stopped and the arc discharge is generated again so that the temperature inside the crucible 30 becomes a constant temperature. Preferably, the temperature gradient may be formed by moving the second electrode 50. The temperature inside the crucible 30 can be maintained to be above the crystal growth temperature (about 2000 ° C.). The temperature can be measured by connecting a thermocouple inside the crucible. Accordingly, temperature gradients are generated in the lower and upper portions of the crucible 30. This temperature gradient causes sublimation of carbon and silicon raw materials, and the temperature is maintained by the heat insulator to maintain the temperature of the crucible 30 at a crystal growth temperature so that the sublimed carbon and silicon gas have relatively low temperature. Go to the positive surface. As a result, the silicon carbide gas is recrystallized to grow into a single crystal.

In this case, the growth rate of the silicon carbide single crystal may be about 200 μm / h or more, preferably 300 μm / h or more.

According to the embodiment, it is possible to provide a new way to grow a single crystal. It is possible to sublimate the raw material using an arc discharge rather than the conventional induction heating method. In addition, the arc discharge reactor can be high technical completion using the existing reactor. Accordingly, by heating the raw material using the arc discharge reactor, it is possible to sublimate the carbon source and silicon source at a faster rate than the amount of carbon and silicon vaporized using induction heating, thereby increasing the single crystal growth rate, This enables fast ingot growth.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (10)

Crucibles containing raw materials;
A first electrode located below the crucible;
A second electrode located above the crucible; And
A seed crystal holder for fixing the seed crystal,
An apparatus for producing ingots, wherein an arc discharge occurs between the first electrode and the second electrode. The method of claim 1,
The raw material is an ingot manufacturing apparatus is vaporized by the heat source generated in the arc discharge. The method of claim 2,
The raw material is an ingot manufacturing apparatus comprising a carbon source, a silicon source or silicon carbide. The method of claim 1,
The second electrode is an ingot manufacturing apparatus containing graphite. The method of claim 1,
Ingot manufacturing apparatus of the first electrode is composed of one or a plurality. The method of claim 1,
The ingot manufacturing apparatus further comprises a vacuum line (vacuum line). The method of claim 1,
The ingot manufacturing apparatus further comprises an ingot manufacturing apparatus (filling line). The method of claim 1,
The ingot production device is an ingot production device for growing a silicon carbide ingot in the seed crystal. Generating an arc discharge between the first electrode and the second electrode;
Vaporizing the silicon carbide raw material by the heat source by the arc discharge; And
And depositing the vaporized silicon carbide in the seed crystal to grow the silicon carbide ingot. The method of claim 9,
The first carbide is made of one or a plurality of silicon carbide ingot manufacturing method.

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