JP4157281B2 - Reactor for silicon production - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a novel apparatus for producing silicon by reaction of chlorosilanes with hydrogen. Specifically, a silicon manufacturing apparatus capable of continuously manufacturing silicon stably at high speed over a long period of time and capable of manufacturing silicon extremely efficiently industrially is provided. To do.
[0002]
[Prior art]
Conventionally, various methods for producing silicon used as a raw material for semiconductors or photovoltaic power generation batteries are known, some of which have already been industrially implemented.
[0003]
For example, one of them is a method called a Siemens method, in which a silicon rod heated to a silicon deposition temperature by energization is placed inside a bell jar, and trichlorosilane (SiHCl) is placed therein. _Three Hereafter referred to as TCS) and monosilane (SiH _Four ) In contact with a reducing gas such as hydrogen to deposit silicon.
[0004]
This method is characterized in that high-purity silicon can be obtained, and is implemented as the most general method, but since precipitation is batch-type, the installation of a silicon rod as a seed, the current heating of the silicon rod, There is a problem that extremely complicated procedures such as precipitation, cooling, taking out, and cleaning of a bell jar must be performed.
[0005]
As another method, there is a deposition method using a fluidized bed. In this method, a fluidized bed is used, while supplying silicon fine particles of about 100 μm as precipitation nuclei, supplying the above-mentioned silanes to deposit silicon on the silicon fine particles, and continuously extracting the silicon particles as 1-2 mm. Is the method. This method is characterized in that it is not necessary to stop the reaction in order to extract silicon, and a relatively long continuous operation is possible.
[0006]
However, in an embodiment that is industrially implemented by this method, since monosilane having a low precipitation temperature is used as a silicon raw material, generation of fine silicon by thermal decomposition of the monosilane or reaction even at a relatively low temperature range Silicon deposition or the like tends to occur on the vessel wall, and it is necessary to periodically clean or replace the reaction vessel. In addition, since the silicon particles in the middle of precipitation in a fluidized state violently contact and rub against the reactor wall for a long time, there remains a problem in the purity of the produced silicon.
[0007]
In order to solve the above-mentioned problems of the existing technology, the temperature of the reactor is heated above the melting point of silicon according to JP-A-59-121109, JP-A-54-124896, and JP-A-56-63813. However, in the reactor, silanes are supplied as deposition raw materials, silicon is deposited and melted, the melt is stored, and the reactor is continuously or intermittently in a molten state or in a state where the melt is cooled and solidified. A method of pulling out has been proposed.
[0008]
However, in particular, the method using monosilane has the property of being easily decomposed even in a relatively low temperature gas to easily generate finely divided silicon, and therefore there is a concern about blockage in the gas downstream region.
[0009]
Further, in any of the conventionally proposed methods, the temperature of the member at the connection part of the reactor and the silane supply pipe or the peripheral part thereof has a temperature gradient from the melting temperature to a temperature at which silicon does not precipitate. In this case, there is always a temperature region where silicon is self-decomposed and deposited, and there is a concern that such a portion may be blocked by the deposited silicon in industrial implementation.
[0010]
On the other hand, Japanese Patent Application Laid-Open No. 11-314996 includes a heat generating solid, a high frequency coil arranged to face the lower surface of the heat generating solid, and at least one gas outlet provided on the coil surface. The raw material gas containing a precipitation component is sprayed from the gas outlet to the lower surface of the exothermic solid that has been induction-heated by the high-frequency coil from the gas outlet, and drops or descends and flows out from the bottom of the exothermic solid to form crystals, for example, An apparatus for producing polycrystalline silicon is disclosed.
[0011]
However, when polycrystalline silicon is produced using this apparatus, the high frequency coil and the heat generating solid are close to each other, so that the high frequency coil that is water-cooled to maintain the function takes the heat of the heat generating solid. There is a problem of low energy efficiency. In addition, in this publication, although means for preventing the precipitation of solid crystals in a low temperature region adjacent to the melting surface is also disclosed, it is limited to means unique to such an apparatus.
[0012]
[Problems to be solved by the invention]
Therefore, it is desired to develop a reaction apparatus that can continuously produce high-purity silicon industrially without causing clogging due to silicon precipitation in a continuous production method by silicon precipitation / melting.
[0013]
[Means for Solving the Problems]
The present inventor has intensively studied to solve the above problems. In the continuous manufacturing method by silicon deposition / melting, silicon is naturally not deposited even if the source gas is not present even in the region heated to the silicon deposition temperature, and the region where the source gas is present is the deposition temperature. Based on the principle that silicon does not substantially precipitate unless it has reached, as a result of investigating the means for solving the above problems,
(1) Supplying the raw material gas directly into the silicon precipitation / melting region and cooling the inner wall of the raw material supply pipe below the silicon precipitation temperature;
(2) Use chlorosilanes whose silicon deposition start temperature is closer to the melting point of silicon than monosilane.
as well as
(3) Supply purge gas so that the inner wall existing in the space above the source gas supply port is disconnected from the source gas.
Thus, it has been found that it is possible to continuously take out molten silicon while suppressing the production of solid silicon in the reactor extremely effectively.
[0014]
In addition, the deposition and melting of the silicon is performed on the inner surface of the cylindrical heating body and the influence on the heating body due to the cooling of the high-frequency coil can be suppressed to an extremely low level. In addition, it is possible to manufacture polycrystalline silicon continuously over a long period of time by adopting a specific gas seal structure based on the above knowledge in such a structure. It has been found that polycrystalline polysilicon can be advantageously produced, and the present invention has been completed.
[0015]
That is, the silicon manufacturing apparatus of the present invention is
(1) A cylindrical container having an opening serving as a silicon outlet at the lower end;
(2) A heating means for heating the inner wall from the lower end of the cylindrical container to an arbitrary height to a temperature equal to or higher than the melting point of silicon,
(3) An inner tube having an outer diameter smaller than the inner diameter of the cylindrical container, wherein one opening of the inner tube is provided downward in a space surrounded by an inner wall heated to a melting point of silicon or higher. Constructed chlorosilanes supply pipe, and
(4) a first seal gas supply pipe for supplying a seal gas to a gap formed by the inner wall of the cylindrical container and the outer wall of the chlorosilane supply pipe;
In some cases,
(5) Hydrogen supply pipe for supplying hydrogen gas into the cylindrical container
It is a polycrystalline silicon manufacturing apparatus characterized by comprising.
[0016]
The hydrogen supply pipe may not be provided when hydrogen is supplied from the first seal gas supply pipe.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the accompanying drawings showing typical embodiments thereof, but the present invention is not limited to these accompanying drawings.
[0018]
1 to 4 are schematic views showing a basic aspect of the polycrystalline silicon production apparatus of the present invention, and FIGS. 5 and 6 are views of a cylindrical container used in the polycrystalline silicon production apparatus of the present invention. It is sectional drawing which shows a typical aspect.
[0019]
In the silicon manufacturing apparatus of the present invention, the cylindrical container 1 has, as a silicon outlet, an opening 2 through which silicon deposited and dissolved in the inside can fall out of the container due to natural flow, as will be described in detail later. Any structure can be used.
[0020]
Therefore, the cross-sectional shape of the cylindrical container 1 can take arbitrary shapes, such as circular shape and polygonal shape. In order to facilitate manufacture, the cylindrical container 1 can be formed in a straight cylinder shape having the same cross-sectional area in each part as shown in FIGS. 1 to 3, and the residence time of the reaction gas can be increased. In order to improve the conversion rate of chlorosilanes to silicon (hereinafter, also simply referred to as conversion rate), it is also preferable to form a part of the cross section as shown in FIG. 4 larger than the other part. is there.
[0021]
On the other hand, the opening method of the opening 2 in the cylindrical container 1 may be a mode in which the opening is straight as shown in FIG. 1 or a mode in which the throttle portion is formed so that the diameter gradually decreases downward. But you can.
[0022]
Moreover, the opening part 2 of the cylindrical container 1 can dripping a silicon melt as a droplet without a problem also in the aspect comprised so that the periphery may become horizontal, but as shown in FIG. By configuring the configuration, and further, the configuration in which the periphery is configured in a wave shape as shown in FIG. 6, the particle diameter of the silicon melt droplet falling from the periphery of the opening 2 can be more uniformly adjusted. This is preferable because it is possible.
[0023]
Further, in any of the shapes of the peripheral edges of the openings described above, it is more preferable to use an edge shape in which the thickness gradually decreases toward the tip in order to improve the liquid drainage when the molten silicon falls.
[0024]
Since the cylindrical container 1 is heated to 1,430 ° C. or more and the inside thereof is in contact with chlorosilanes or silicon melt, it is long to select a material that can sufficiently withstand these temperature conditions and contact objects. It is desirable for manufacturing silicon with a stable period.
[0025]
Examples of such materials include carbon materials such as graphite, silicon carbide (SiC), and silicon nitride (Si ₃ N ₄ ), Boron nitride (BN) and aluminum nitride (AlN) or other ceramic materials such as single materials or composite materials.
[0026]
Of these materials, a carbon material is used as a base material, and at least a portion in contact with the silicon melt is coated with silicon nitride, boron nitride, or silicon carbide, so that the life of the cylindrical container can be remarkably increased. Particularly preferred for use. Among these, silicon nitride or boron nitride is most preferable because these materials have poor wettability with respect to the silicon melt, so that the material flows down from the cylindrical container and drains well.
[0027]
In the silicon manufacturing apparatus of the present invention, the cylindrical container 1 is provided with heating means 3 for heating the peripheral wall from the lower end to an arbitrary height to a temperature equal to or higher than the melting point of silicon. The width to be heated to the above temperature, that is, the height at which the heating means 3 is provided from the lower end of the cylindrical container 1 takes into account the size of the cylindrical container, the heating temperature, and the amount of chlorosilanes to be supplied. Generally, the range of the cylindrical container heated above the melting point of silicon by the heating means is 20 to 90% from the lower end with respect to the entire length of the cylindrical container 1, preferably, The length is determined to be 30 to 80%.
[0028]
Any known means can be used as the heating means 3 as long as the inner wall of the cylindrical container can be heated to the melting point of silicon or higher, that is, 1,430 ° C. or higher.
[0029]
As a specific example of the heating means, as shown in FIG. 1, there is a means for heating the inner wall of the cylindrical container by energy from the outside. More specifically, there are a heating method using high frequency, a heating means using a heating wire, a heating means using infrared rays, and the like.
[0030]
Among these methods, the heating method using high frequency is preferable because the cylindrical container can be heated to a uniform temperature while simplifying the shape of the heating coil that emits high frequency.
[0031]
In the silicon production apparatus of the present invention, the chlorosilanes supply pipe 5 is for directly supplying the chlorosilanes A to the space 4 surrounded by the inner wall of the cylindrical container 1 heated to the melting point of silicon or more. 4 is provided so as to open downward.
[0032]
Note that “downward” indicating the opening direction of the chlorosilane supply pipe 5 is not limited to the vertical direction, and includes all modes in which the supplied chlorosilanes are opened so as not to contact the opening again. However, the most preferable embodiment is an embodiment in which the supply pipe is provided in a direction perpendicular to the plane.
[0033]
Also, chlorosilanes supplied from the chlorosilane supply pipe 5 have a higher thermal decomposition temperature than monosilane, which is another silicon raw material, and the inside of the pipe is heated in the space 4 of the cylindrical container heated above the melting point of silicon. In order to prevent degradation of the supply pipe due to heat and to prevent the chlorosilanes from being decomposed in a small amount, a cooling means for cooling the supply pipe is provided. It is preferable.
[0034]
Although the specific aspect of a cooling means is not restrict | limited in particular, For example, as shown in FIG. ₁ Supplied from D ₂ A liquid jacket system for cooling by providing a flow path designed to discharge more, although not shown, a multi-ring nozzle more than a double pipe is provided in the chlorosilane supply pipe, chlorosilanes are supplied from the center, and the outer ring For example, an air-cooling jacket system in which cooling gas is purged from the nozzle to cool the central nozzle.
[0035]
The cooling temperature of the chlorosilanes supply pipe only needs to be cooled to such an extent that the material constituting the supply pipe does not deteriorate significantly, and in general, it may be set below the self-decomposition temperature of the supplied chlorosilanes. It is preferable to cool to 600 ° C. or lower. More preferably, specifically, TCS or silicon tetrachloride (SiCl ₄ , Hereinafter referred to as STC) is preferably 800 ° C. or less, more preferably 600 ° C. or less, and most preferably 500 ° C. or less.
[0036]
As a material of the chlorosilane supply pipe 5, in addition to the same material as the cylindrical container 1, quartz glass, iron, stainless steel, and the like can be used.
[0037]
In the silicon manufacturing apparatus of the present invention, as shown in FIG. 4, in an aspect in which an enlarged portion is provided in a part of a cylindrical container, the opening of the chlorosilanes supply pipe may be provided in the space of the enlarged portion. preferable. By doing so, the opening can be separated from the heated inner wall, and cooling for preventing the deposition of silicon in the chlorosilane supply pipe can be performed more easily.
[0038]
In the present invention, the first seal gas supply pipe 7 supplies the seal gas B to a gap formed by the inner wall of the cylindrical container existing above the opening position of the chlorosilane supply pipe 5 and the outer wall of the chlorosilane supply pipe. To be provided. That is, the present invention prevents chlorosilanes supplied as a raw material from depositing solid silicon on the inner wall of a cylindrical container in contact with a low temperature region where silicon can be precipitated but cannot be melted. Therefore, chlorosilanes are directly supplied to a high-temperature space where silicon melting occurs. However, a similar low temperature region exists in the gap formed by the inner wall of the cylindrical container and the outer wall of the chlorosilane supply pipe.
[0039]
Therefore, in the apparatus of the present invention, a mixed gas of chlorosilanes and hydrogen is provided by providing the first seal gas supply pipe 7 for supplying seal gas to the gap and filling the gap in which the low temperature region exists with the seal gas. Can effectively prevent solid silicon from being deposited in the low temperature region.
[0040]
In the present invention, the first seal gas supply pipe 7 is not particularly limited as long as it is above the opening position of the chlorosilane supply pipe 5, but it is preferable to provide the first seal gas supply pipe 7 on the wall surface of the cylindrical container where the heating means 3 does not exist.
[0041]
The seal gas supplied from the first seal gas supply pipe 7 is preferably a gas that does not generate silicon and does not adversely affect the generation of silicon in the region where chlorosilanes are present. Specifically, an inert gas such as argon or helium, hydrogen described later, or the like is preferable.
[0042]
In this case, it is sufficient that the seal gas is supplied to such an extent that the pressure that always fills the space where the temperature gradient exists is maintained. In order to reduce the supply amount, the shape of the cylindrical container 1 or the shape of the outer wall of the chlorosilanes supply pipe may be determined so as to reduce the entire space or the sectional area of the lower part.
[0043]
In the silicon production apparatus of the present invention, the hydrogen supply pipe for supplying hydrogen to be used for the precipitation reaction together with the chlorosilanes is located at a position where it can be supplied to the cylindrical container 1 and the space 4 independently of the chlorosilanes supply pipe 5. If it opens, it will not restrict | limit in particular.
[0044]
Therefore, it is preferable to appropriately provide a portion where the reaction with the chlorosilane can be efficiently performed in consideration of the structure, size, and the like of the cylindrical container 1 constituting the silicon manufacturing apparatus. Specifically, as shown in FIG. 1, a mode in which hydrogen C is supplied as a seal gas to the first seal gas supply pipe 7 is suitable. Moreover, the aspect which attaches the hydrogen supply pipe | tube 8 for supplying hydrogen C to the side wall of the cylindrical container 1 is also mentioned. Of course, the above two modes can be used in combination.
[0045]
As described above, the polycrystalline silicon manufacturing apparatus of the present invention has
(1) Precipitate and melt silicon on the inner surface of the cylindrical container,
(2) Insert a supply pipe for chlorosilanes into the melting zone of silicon in the cylindrical container, and
(3) It has a structure for supplying a sealing gas into a gap between the cylindrical container and a supply pipe for chlorosilanes.
[0046]
With the configuration of (1) above, the thermal efficiency of the heating surface for depositing and melting silicon can be made extremely high, which is industrially very advantageous.
[0047]
Further, the combination of (2) and (3) makes it possible to completely prevent solid silicon from being deposited and not melted in the apparatus.
[0048]
In the silicon production apparatus of the present invention, other structures are not particularly limited, but the following embodiments can be given as examples of preferred embodiments. For example, in order to efficiently recover the exhaust gas generated in the cylindrical container 1, the silicon melt droplets melted and dropped from the opening 2 of the cylindrical container 1 are cooled and solidified without contact with the outside air. In order to do this, an embodiment in which at least the lower end opening of the cylindrical container is covered with the sealed container 10 connected to the exhaust gas exhaust pipe 12 is preferable. Thereby, high purity silicon can be obtained industrially.
[0049]
A representative embodiment of the sealed container 10 is shown in FIGS. It is preferable that the opening 2 corresponding to the silicon outlet of the cylindrical container 1 is covered to form a cooling space 15 in which the silicon melt can fall, and a gas discharge pipe 12 for discharging exhaust gas is provided. .
[0050]
The sealed container 10 may be provided so as to cover the lower end of the cylindrical container in a state in which the edge of the opening 2 of the cylindrical container 1 protrudes. For example, the outer periphery of the cylindrical container in the vicinity of the opening You may connect with.
[0051]
However, since there is a high possibility that there is a low temperature region where the solid silicon is deposited on the surface of the closed container at a position away from the connection point, as shown in FIGS. 3 and 4, it is separated from the high temperature region including the opening. It is preferable that the connection is made on the outer periphery of the upper portion of the cylindrical container, or the entire cylindrical container is covered.
[0052]
Chlorosilanes present in the gas discharged from the cylindrical container 1 are approaching a stable gas composition in which no more silicon is deposited, and even if silicon is deposited, the amount is small.
[0053]
However, in order to prevent the precipitation of solid silicon as much as possible in the sealed container 10, as shown in FIGS. 3 and 4, as shown in FIG. 3 and FIG. A mode in which the second seal gas supply pipe 11 for supplying E is provided is preferable.
[0054]
The type, supply amount, and the like of the seal gas can be determined in the same manner as when the seal gas is supplied to the first seal gas supply pipe 7.
[0055]
In the above embodiment, in order to fully exhibit the effect of the seal gas, the linear velocity of the seal gas flowing around the cylindrical container 1 is at least 0.1 m / s, preferably 0.5 m / s, most preferably Is preferably 1 m / s or more.
[0056]
Metal materials, ceramic materials, glass materials, etc. can be suitably used as the material of the sealed container 10, but in order to achieve both robustness and high-purity silicon recovery as industrial equipment, metal recovery is possible. More preferably, the interior of the chamber is lined with silicon, Teflon, quartz glass or the like.
[0057]
On the other hand, the exhaust gas after the reaction in the cylindrical container 1 is taken out from a gas discharge pipe 12 provided in the sealed container 10.
[0058]
Further, the molten silicon melted and dropped from the cylindrical container 1 is cooled and solidified as silicon 23 is cooled by falling in the cooling space 15 of the sealed container 10 or by contacting with the coolant present on the bottom surface at the time of dropping. Accumulated at the bottom of the container and cooled to a temperature that is easy to handle. When the cooling space is set sufficiently long, granulated silicon can be obtained, and when the cooling space is short, solid silicon plastically deformed by a drop impact can be obtained.
[0059]
In order to promote the cooling, it is a preferable aspect to provide the supply pipe 13 for the cooling gas H. In addition, although not shown in the drawing, a solid or liquid coolant is separately provided on the bottom surface of the sealed container 10 to cool the silicon melt droplets more powerfully as necessary. be able to. Silicon, copper, molybdenum, or the like can be used as the solid coolant, and liquid silicon tetrachloride, liquid nitrogen, or the like can be used as the liquid coolant.
[0060]
In addition, the closed container 10 may be provided with an outlet 17 for continuously or intermittently extracting the solidified silicon I as necessary. As for the form of the outlet, it is preferable to adopt a structure in which the lower part of the hermetic container can be replaced when silicon is obtained in an agglomerated state where the silicon is partially fused.
[0061]
In order to cool the silicon more effectively, it is preferable to provide a cooling device 14 in the sealed container 10. For example, as shown in FIGS. 3 and 4, the cooling mode is such that a coolant liquid such as water, heat transfer oil, alcohol, etc. ₁₁ To F ₁₂ , F ₂₁ To F ₂₂ Or F ₃₁ To F ₃₂ It is most preferable to use a liquid jacket system in which a flow path is provided for cooling and cooling.
[0062]
As shown in FIGS. 3 and 4, when the sealed container 10 is joined at the upper part of the cylindrical body, a cooling medium such as heat medium oil can be circulated in an appropriate jacket structure for material protection, If the material has heat resistance, it can be kept warm by applying a heat insulating material in order to enhance the thermal effect.
[0063]
【effect】
As can be understood from the above description, the polycrystalline silicon manufacturing apparatus of the present invention is suitable for the method of manufacturing the polycrystalline silicon foam, and at the same time, converts polycrystalline silicon containing polycrystalline silicon in a form other than those described above at high speed. In addition, it is an industrially extremely useful apparatus that can be stably and continuously manufactured for a long period of time.
[0064]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these examples.
[0065]
【Example】
Example 1
As shown below, a polycrystalline silicon manufacturing apparatus similar to that shown in FIG. 3 was constructed, and polycrystalline silicon was continuously manufactured.
[0066]
A high-frequency heating coil was installed as a heating means 3 around the cylindrical container 1 made of silicon carbide having an inner diameter of 25 mm and a length of 50 cm and having an opening 2 at the lower part, from the position of the upper part 10 cm to the lower end. A stainless steel chlorosilane supply pipe 5 having an inner diameter of 10 mm and an outer diameter of 17 mm having a jacket structure capable of passing liquid as shown in FIG. 2 was inserted from the upper end of the cylindrical container to a height of 15 cm. The sealed container 10 was made of stainless steel having an inner diameter of 500 mm and a length of 3 m.
[0067]
In addition, the periphery of the lower end of the said cylindrical container was made into the shape shown in FIG.
[0068]
Water is passed through the cooling jacket of the chlorosilane supply pipe to maintain the inside of the pipe at 50 ° C. or lower, and is also passed through the lower jacket of the sealed container 10. After flowing hydrogen gas through the seal gas supply pipe 11 at the upper part of the container 10 at a rate of 5 L / min, the high frequency heating means was activated to heat the cylindrical container 1 to 1,500 ° C. The pressure in the container was almost atmospheric pressure.
[0069]
When trichlorosilane was supplied to the chlorosilanes supply pipe 5 at a rate of 10 g / min, granular silicon droplets having a substantially uniform particle size at a rate of about 0.6 g / min were observed during natural fall. In this case, the conversion rate of trichlorosilane was about 30%.
[0070]
The silicon melt was separated and dropped from the opening of the cylindrical container. At this time, the tip of the lower opening of the cylindrical container was sufficiently wet with silicon, and the surface was covered with silicon.
[0071]
After the reaction was continued for 50 hours, the operation was stopped and the inside of the apparatus was observed open. As a result, no clogging with silicon occurred.
[0072]
Example 2
The silicon production apparatus shown in FIG. 4 was configured as follows, and silicon was continuously obtained by the following method using the apparatus.
[0073]
The inner diameter of the insertion part of the chlorosilanes supply pipe 5 and the opening 2 is 25 mm, the inner part is enlarged to 50 mm over 20 cm in the vicinity of the center, and the tapered part is formed with a length of 5 cm, respectively. A high-frequency heating coil was installed as a heating means 3 around the cylindrical container 1 made of silicon carbide around the upper end 10 cm to the lower end. A stainless steel chlorosilane supply pipe 5 having an inner diameter of 10 mm and an outer diameter of 17 mm having a jacket structure capable of passing liquid as shown in FIG. 2 was inserted from the upper end of the cylindrical container 1 to a height of 15 cm. The sealed container 10 was made of stainless steel having an inner diameter of 750 mm and a length of 3 m.
[0074]
In addition, the periphery of the lower end of the said cylindrical container was made into the shape shown in FIG.
[0075]
Water is passed through the cooling jacket of the chlorosilanes supply pipe to maintain the inside of the pipe at 50 ° C. or lower, and is also passed through the lower jacket of the sealed container. After flowing hydrogen gas through the seal gas supply pipe 21 at the upper part of each, 5 L / min, the high frequency heating means was started and the cylindrical container 1 was heated to 1,500 ° C. The pressure in the container was almost atmospheric pressure.
[0076]
When trichlorosilane was supplied to the chlorosilanes supply pipe 5 at a rate of 10 g / min, granular silicon droplets having a substantially uniform particle size at a rate of about 1 g / min were observed during spontaneous fall. In this case, the conversion rate of trichlorosilane was about 50%.
[0077]
After the reaction was continued for 50 hours, the operation was stopped and the inside of the apparatus was observed open. As a result, no clogging with silicon occurred.
[0078]
Comparative Example 1
The operation was carried out under the same apparatus and conditions as in Example 1 except that the raw material was changed from trichlorosilane to monosilane and supplied at a rate of 2 g / min.
[0079]
At the beginning of operation, granular silicon could be obtained at a rate of 1.5 g / min or more, but a large amount of silicon fine powder accumulated in the cooling recovery chamber and the gas discharge line 26, making it impossible to continue operation in about 5 hours. became.
[0080]
Comparative Example 2
The stainless steel chlorosilanes supply pipe 5 having the cooling jacket structure 6 of Example 1 and having an inner diameter of 10 mm and an outer diameter of 17 mm is 5 cm high from the upper part of the cylindrical container (by an inner wall having a temperature lower than the melting point of silicon). Inserted up to the enclosed space). The other operation was performed under the same conditions as in Example 1.
[0081]
At the beginning of operation, granular silicon could be obtained at a rate of about 0.6 g / min, but after about 15 hours it became difficult to supply trichlorosilane and seal hydrogen.
[0082]
When the opening was observed after the stop, the vicinity of the upper part inside the cylindrical container 1 was almost closed. The occlusion was silicon.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a typical embodiment of a silicon manufacturing apparatus according to the present invention.
FIG. 2 is a conceptual diagram showing another typical aspect of the silicon manufacturing apparatus of the present invention.
FIG. 3 is a conceptual diagram showing another typical aspect of the silicon manufacturing apparatus of the present invention.
FIG. 4 is a conceptual diagram showing another typical aspect of the silicon manufacturing apparatus of the present invention.
FIG. 5 is a conceptual diagram showing the shape of the peripheral edge of the lower end of a cylindrical container in the silicon manufacturing apparatus of the present invention.
FIG. 6 is a conceptual diagram showing the shape of the periphery of the lower end of a cylindrical container in the silicon manufacturing apparatus of the present invention.
[Explanation of symbols]
1 cylindrical container
3 Heating means
5 Chlorosilane supply pipe
6 Cooling means
7 First seal gas supply pipe
11 Second seal gas supply pipe
8 Hydrogen gas supply pipe
10 Airtight container
14 Cooling jacket
12 Gas exhaust pipe
17 Silicon outlet
13 Cooling gas supply pipe

Claims (8)

  (1) A cylindrical container having an opening serving as a silicon outlet at the lower end, (2) a heating means for heating the inner wall from the lower end of the cylindrical container to an arbitrary height to a temperature equal to or higher than the melting point of silicon, (3) An inner tube having an outer diameter smaller than the inner diameter of the cylindrical container, wherein one opening of the inner tube is provided downward in a space surrounded by an inner wall heated to a melting point of silicon or higher. A polycrystal comprising: a chlorosilane supply pipe; and (4) a first seal gas supply pipe for supplying a seal gas to a gap formed by an inner wall of the cylindrical container and an outer wall of the chlorosilane supply pipe. Silicon manufacturing equipment. (5) The apparatus according to claim 1, further comprising a hydrogen gas supply pipe for supplying hydrogen gas into the cylindrical container.   The silicon manufacturing apparatus according to claim 1 or 2, wherein the cylindrical container is made of a carbon material as a base material, and at least an inner wall in contact with the silicon melt is coated with silicon nitride, boron nitride, or silicon carbide.   The silicon manufacturing apparatus according to claim 1, wherein the heating means is formed by providing a high-frequency coil on the outer periphery of the cylindrical container.   Any one of Claims 1-4 which has the airtight container which covers the at least lower end part of the said cylindrical container, and forms a space under the said cylindrical container, The said exhaust pipe was provided with piping for gas discharge | emission A silicon manufacturing apparatus according to claim 1. The silicon manufacturing apparatus according to claim 5, further comprising a second seal gas supply pipe that supplies a seal gas to a gap formed by an outer wall of the cylindrical container and an inner wall of the sealed container.   The silicon production apparatus according to claim 1, further comprising a cooling unit that cools the chlorosilanes supply pipe. A chlorosilane and hydrogen are supplied to the silicon production apparatus according to any one of claims 1 to 7 , and silicon is generated under a condition that a conversion rate from the chlorosilane to silicon is 25% or more. To manufacture silicon.

Images