JP2006124832A - Vapor phase growth system and vapor phase growth method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase growth system capable of enhancing the durability of a reaction vessel and further enhancing exhaust efficiency and efficiently depositing high-quality deposit, and to provide a vapor phase growth method. <P>SOLUTION: The pulse CVD system is equipped with the reaction vessel, a heating apparatus for controlling heating of an object to be treated arranged on a stage in the reaction vessel, a treatment gas supply system for supplying the treatment gas from a treatment gas generation source into the reaction vessel, and an exhaust system having an exhaust pump, controlling the inside of the reaction vessel to a reduced pressure and exhausting the inside of the reaction vessel, and performs the supply and exhaust of the treatment gas to and from the reaction vessel repeatedly a prescribed number of times, wherein the reaction vessel is a double tube structure consisting of an inner tube and an outer tube and an outer tube and in addition, a treatment gas storage vessel for temporarily storing the treatment gas is arranged between the reaction vessel and the treatment gas generation source, and an exhaust gas storage vessel for temporarily storing the exhaust gas is arranged between the reaction vessel and the vacuum pump. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vapor phase growth apparatus and a vapor phase growth method.

  Vapor phase epitaxy is a method in which a processing gas is introduced into a reaction vessel containing an object to be processed, and a reaction product derived from the processing gas is deposited on the object to be processed by a thermal decomposition reaction. in use. As one of the vapor phase deposition methods, there is a vapor phase chemical impregnation method (CVI: Chemical Vapor Infiltration) in which a porous substrate is used as an object to be treated and various substances such as ceramics, carbon, and metal are deposited including the inside of the pores. Are known. This CVI method is a method in which a processing gas is fed into the pores of a porous substrate, and a reaction product derived from the processing gas is deposited using a thermal decomposition reaction or the like.

  The CVI method is classified into reduced pressure CVI, forced flow type CVI, pulse CVI, etc., depending on the type of precipitation process. The reduced pressure CVI is a method of increasing the gas diffusion rate by reducing the pressure in the reaction vessel and promoting the material transport into the pores. The forced flow type CVI is a method in which a gas is circulated through a porous substrate, a processing gas is forcibly introduced into the pores, and a generated gas is discharged. The pulse CVI method is a method in which the pressure reduction and pressure increase of the reaction vessel are repeated in a short cycle, the processing gas is intermittently supplied into the pores, and the generated gas is discharged. Among these, the pulse CVI method is known to be excellent in uniform film formation inside a porous substrate because of the form of gas supply / discharge.

  However, in the pulse CVI method, since the reaction vessel repeatedly receives pressure reduction and pressure increase, the reaction vessel is particularly required to have pressure resistance. Conventionally, reaction vessels made of quartz glass have been used (see Patent Document 1 and Patent Document 2). Since quartz glass is softened and deformed at 1000 ° C. or higher, a material that requires a reaction temperature of 1000 ° C. or higher is deposited. I can't let you. In particular, when the apparatus is enlarged, the problem of softening deformation increases. In addition, quartz glass has a drawback that it easily brittlely breaks due to impact or overload.

  In order to realize a reaction temperature of 1000 ° C. or higher, a method using heat-resistant ceramics such as SiC instead of quartz glass is also conceivable. However, it is difficult to guarantee the strength of large ceramic parts due to the brittleness of ceramics. In addition, in order to increase the productivity, if the temperature of the reaction vessel is rapidly raised and rapidly cooled, the weak thermal shock resistance of ceramics becomes a problem.

  A method of creating a reaction tube with a refractory metal instead of quartz glass or ceramics is also conceivable, but in this case, corrosion resistance becomes a problem. For example, when a Ni-based heat-resistant alloy such as Inconel is used, a Ni—Si based intermetallic compound is formed on the surface of the Ni-based heat-resistant alloy when it is brought into contact with a processing gas containing Si at a high temperature. NiSi has the lowest melting point among Ni-Si based intermetallic compounds, and its eutectic point is 970 ° C. Therefore, when the temperature of the reaction vessel is increased to 970 ° C. or more, the Ni-base alloy is eroded by the liquid phase NiSi, and in the worst case, corrosion holes are opened. A similar problem occurs because heat-resistant alloys other than Ni-based alloys also contain Ni.

  In addition, the carbonaceous reaction tube is housed in a metal sealed container, and the carbonaceous reaction tube is heated with a heater housed in the sealed container (see Patent Document 3). It is also practiced to improve the airtightness of the reaction tube by coating with permeable SiC (see Patent Document 4). However, in the apparatus of Patent Document 3, (1) the cooling rate is slow: the reaction tube, the heater, and the heat insulating material are housed in the sealed container, so the heat capacity is large and it is difficult to cool down. (2) Samples are frequently taken out There is a problem that the sample cannot be taken out unless two or more flanges are removed because the sample is stored in a double sealed container. Moreover, in the apparatus of patent document 4, there exists a problem in the reliability of a SiC covering carbon tube. In the embodiment, it is said that the device has endured 50 times. However, for example, if the SiC layer cracks due to rapid cooling, there is a risk that the oxidation of the carbonaceous reaction tube proceeds rapidly. In addition, if a tool or the like is struck against the reaction tube due to careless handling, the SiC layer falls off, and oxidation of the carbonaceous reaction tube proceeds. In the pulse CVI method, hydrogen is often used as a processing gas to be used, and if it leaks, there is a high risk of explosion, and the SiC-coated carbon tube is difficult to manage and is not practical.

  Furthermore, in the pulse CVI method, the introduction of the processing gas and the exhaust of the generated gas are repeated, and the reaction is performed many times. Therefore, if the reaction varies, a high-quality precipitate cannot be obtained. Therefore, exhaust is particularly important. However, if exhaust is sufficiently performed for a long time, the processing efficiency is lowered. Although it is conceivable to increase the size of the vacuum pump, the equipment cost and the operation cost are incurred. Industrially, it is desired to increase the capacity of the reaction vessel and process a large number of porous substrates at once, but the problem of exhaustion is a major obstacle.

Similarly, general vapor phase growth apparatuses and vapor phase growth methods also have problems such as corrosion and durability due to processing gas in the reaction vessel, processing efficiency associated with exhaust time, and safety.
JP-A-8-91963 Japanese Patent Laid-Open No. 8-188489 Japanese Patent Laid-Open No. 6-345569 JP-A-6-57433

  The present invention has been made in view of the situation as described above, and improves the durability of the reaction vessel, further increases the exhaust efficiency, and allows a vapor deposition apparatus and a gas deposition apparatus that can efficiently deposit high-quality precipitates. The object is to provide a phase growth method.

In order to solve the above-described problems, the present invention provides a vapor phase growth apparatus and a vapor phase growth method described below.
(1) A reaction vessel, a heating device that controls the heating of a target object disposed on a sample stage in the reaction vessel, and a processing gas supply system that supplies a processing gas from a processing gas generation source into the reaction vessel. And a gas phase growth apparatus comprising an exhaust system that has an exhaust pump and controls the inside of the reaction vessel to a reduced pressure and exhausts the inside of the reaction vessel.
The reaction vessel has a double tube structure composed of an inner tube and an outer tube, and a processing gas storage vessel for temporarily holding a processing gas is disposed between the reaction vessel and the processing gas generation source, and the reaction A vapor phase growth apparatus characterized in that an exhaust gas storage container for temporarily holding exhaust gas is disposed between the container and the vacuum pump.
(2) The vapor phase growth apparatus as described in (1) above, wherein a bypass pipe for bypassing the exhaust gas storage container is provided between a gas introduction pipe and a gas exhaust pipe of the exhaust gas storage container.
(3) A space between the outer tube and the inner tube of the reaction vessel is kept airtight, and a non-oxidizing gas supply system that supplies a non-oxidizing gas to the space, and a non-oxidizing gas from the space The vapor phase growth apparatus as described in (1) or (2) above, further comprising a non-oxidizing gas exhaust system for exhausting gas.
(4) The gas according to any one of (1) to (3) above, wherein a trap mechanism filled with inorganic fibers is disposed between the reaction vessel and the exhaust gas storage vessel. Phase growth equipment.
(5) The above-described (1) to (4), wherein an abatement facility is disposed downstream of the exhaust pump, and an inner surface of a metal container provided in the abatement facility is coated with a corrosion-resistant resin. The vapor phase growth apparatus of any one.
(6) The vapor phase growth apparatus according to any one of (1) to (5) above, further comprising a moving / separating means for separating the heating apparatus and the reaction vessel.
(7) A vapor phase growth method in which an object to be processed is arranged in a reaction vessel, a process gas is tested while heating the reaction vessel, and a substance deposited on the object by the reaction of the process gas is vapor phase grown. In
A first step of disposing the object to be processed in a reaction vessel having a double tube structure comprising an outer tube and an inner tube;
A second step of heating the object to be processed;
A third step of controlling the inside of the reaction vessel to a reduced pressure;
A fourth step of supplying a processing gas to the processing gas storage container in the reaction container and temporarily holding the processing gas;
A fifth step of supplying the processing gas from the processing gas storage container into the reaction container and temporarily holding the processing gas in the reaction container;
A sixth step of evacuating the reaction vessel and temporarily holding the exhaust gas in the exhaust gas storage vessel, and
A vapor phase growth method characterized in that an airtight space formed between the outer tube and the inner tube is maintained in a non-oxidizing gas atmosphere between the second step to the sixth step.
(8) The vapor phase growth method as described in (7) above, wherein the third to sixth steps are repeated.
(9) The vapor phase growth method as described in (7) or (8) above, further comprising a seventh step of exhausting the inside of the reaction vessel directly by bypass piping bypassing the exhaust gas storage vessel.
(10) The vapor phase growth method as described in (9) above, wherein the third to seventh steps are repeated.
(11) The vapor phase growth method according to any one of (7) to (10) above, further comprising a step of separating the heating device and the reaction vessel after processing.

  In the vapor phase growth apparatus of the present invention, durability is enhanced by using a reaction vessel having a double structure and maintaining a non-oxidizing gas atmosphere during processing. In addition, since a processing gas storage container that temporarily stores processing gas, an exhaust gas storage container that temporarily stores exhaust gas, and a bypass pipe that bypasses the exhaust gas storage container, the processing gas can be stably supplied and the exhaust efficiency can be improved. .

  Moreover, the vapor phase growth method of the present invention can efficiently deposit a substance derived from the processing gas on the object to be processed by using the above apparatus.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Here, the case where silicon carbide is deposited on the object to be processed by the pulse CVI method is shown.

  FIG. 1 is a schematic diagram showing the main part of the pulse CVI apparatus, which is divided into a processing gas supply system, a reaction part, and an exhaust system.

The processing gas supply system includes a processing gas generator 10 and a processing gas storage container 20. The processing gas generator 10 includes a bubbling tank 11 that stores, for example, liquefied silicon tetrachloride (SiCl ₄ ), and supplies hydrogen gas (H ₂ ) as a raw material gas to bubbling the silicon tetrachloride as a raw material gas. Generate gas. A regulator RG5, a flow meter FM5, and an air operated valve (hereinafter referred to as “valve”) V5 are connected to the hydrogen gas cylinder, and the flow rate and supply timing are controlled. The flow rate of the generated silicon tetrachloride gas is adjusted by a manual flow rate adjusting valve NV1, and the supply to the processing gas storage container 20 is controlled by the valve V6.

  The flow rate adjustment valve NV1 functions as a pressure cutoff valve, and the amount of silicon tetrachloride generated is stabilized by appropriately reducing the opening degree. When there is no pressure cutoff valve, the pressure of the bubbling tank 11 fluctuates in a pulse manner in conjunction with the pressure of the processing gas storage container 20. For example, when the pressure in the bubbling tank 11 decreases, the amount of source gas generated increases from a predetermined amount. Therefore, if a pressure shut-off valve is provided and is appropriately throttled, pressure fluctuations in the bubbling tank 11 are suppressed, and the amount of source gas generated is stabilized.

The processing gas supply system includes gas cylinders of methane (CH ₄ ), hydrogen gas (H ₂ ) serving as source gases, and argon gas (Ar) as a purge gas, and each gas is processed by valves V2 to V4. Supply to the storage container 20 is controlled. In the figure, symbols RG2 to RG4 are regulators, and FM2 to FM4 are flow meters.

  The reaction unit includes a reaction vessel 30 and a heating device 50 that surrounds and heats the reaction vessel 30. As shown in FIG. 2, the reaction vessel 30 has a double structure of an inner tube 31 and an outer tube 32. The inner tube 31 needs to have corrosion resistance in order to come into contact with the processing gas, and artificial isotropic graphite is suitable. In order to reduce gas permeability, the inner tube 31 may be clogged with carbon by applying a phenolic resin to the inner wall, heating to about 1000 ° C., and carbonizing. Further, since the outer tube 32 is directly heated by the heating device 40, a heat-resistant alloy, for example, a Ni-based alloy such as Inconel is suitable.

  In the reaction vessel 30, the inner tube 31 and the outer tube 32 have an airtight structure. In order to obtain an airtight structure, for example, a structure as shown in the enlarged view of the portion A can be used. That is, the lower end of the outer tube 32 is formed with a flange 32a that protrudes perpendicularly from the outer peripheral surface and then hangs down in parallel with the outer peripheral surface. A ring-shaped space is formed between the outer tube 32 and the outer peripheral surface. Form. The inner tube 31 has a flange 31 a that slightly protrudes at the lower end thereof, and a gap between the outer tube 32 and the flange 32 a is sealed with a rubber packing 33. A first presser ring 36 is accommodated in the space between the inner tube 31 and the flange 32a of the outer tube 32 with an O-ring 35 interposed therebetween. Two presser rings 37 are accommodated, and both presser rings 36 and 37 are fixed to the flange 32 a of the outer tube 32 by ring fixing bolts 38. Then, by fixing the flange 32a of the outer tube 32 to the lower flange 39 of the reaction vessel with the fixing bolt 41 via the O-ring 40, the reaction vessel 30 has an airtight structure.

  A non-oxidizing gas is circulated between the inner tube 31 and the outer tube 32 during the reaction. For gas supply and exhaust, an introduction port and an exhaust port may be provided at appropriate positions of the outer tube 32. As a result, even if a small amount of processing gas leaks from the carbon inner pipe 31, the processing gas is eliminated from the reaction section, so that there is no risk of corrosion of the outer pipe 32. As the non-reactive gas, argon gas is supplied in FIG. 1, but nitrogen gas may be used.

  The lower flange 39 is provided with a gas introduction / exhaust port, and a carbon sample stage 45 on which a workpiece 43 such as a porous body is placed is fixed. The sample stage 45 is provided with a gas passage 45a for introducing a processing gas and exhausting a generated gas. The introduction of the processing gas is controlled by a valve V7 and the exhaust is controlled by a valve V8.

  The heating device 50 is not limited as long as it has a size that can surround the reaction vessel 30 and can uniformly heat the inside.

  In the reaction part, it is preferable that the reaction vessel 30 and the heating device 50 can be separated from each other. As a separation method, as shown in FIG. 3, the reaction vessel 30 and the heating device 40 may be moved by a crane 55. That is, after placing the object to be processed 43 on the sample stage (FIG. 1A), the reaction vessel 30 is lifted by the crane 55 and covered with the reaction vessel 30 (FIG. 1B). 50 is lifted and arranged so as to cover the reaction vessel 30, and after the treatment, the heating vessel 50 is lifted and removed by the crane 55 ((C) in the figure). Thereby, after the treatment, the reaction vessel 30 is cooled by the outside air, and the cooling time is greatly shortened as compared with the case where the temperature of the heating vessel 50 is lowered while being accommodated in the heating vessel 50. At that time, although the reaction vessel 30 has a double structure, since only one end is fixed, thermal stress due to a difference in thermal expansion between the inner tube 31 and the outer tube 32 does not occur even when rapidly cooled.

  The exhaust system includes an exhaust gas storage container 60 and a vacuum pump 70. Gas introduction into the exhaust gas storage container 60 is controlled by a valve V9 and exhaust is controlled by a valve V11. Further, a valve V10 is provided so as to bypass both valves V9 and V11, and the exhaust gas storage container 60 can be exhausted more efficiently by operating the valve. Further, a non-oxidizing gas exhaust pipe from the reaction vessel 30 is connected to the vacuum pump 70 and is controlled by a valve V13.

  By the way, since the exhaust gas from the reaction vessel 30 includes a product that is not deposited on the object to be processed and remains floating, if it is exhausted as it is, the piping and the vacuum pump 70 are clogged. Therefore, in order to purify the exhaust gas from the reaction vessel 30, it is preferable to insert the trap mechanism 80 in front of the exhaust gas storage vessel 60. For example, as shown in FIG. 4, the trap mechanism 80 is a tubular body 81 filled with glass wool 82, and the upper and lower opening surfaces are held by holding wire nets 83, 83, and a fluororubber packing 84 is interposed therebetween. And connected to the piping.

  Further, it is desirable to provide an exhaust gas processing device 90 for processing the exhaust gas from the vacuum pump 70 to make it harmless. The exhaust gas treatment device 90 is preferably configured by storing a treatment liquid (for example, a neutralization liquid) 92 in a metal container 91 and covering the inner surface of the container 91 with a corrosion-resistant resin. Reference numeral 91 denotes a circulation pump for circulating the treatment liquid 92.

  Further, in order to increase the exhaust efficiency of the processing gas storage container 20, it is preferable to provide a bypass pipe 100 that bypasses the gas exhaust pipe of the processing gas storage container 20 and the gas exhaust pipe of the exhaust gas storage container 60. A valve V12 is connected to the bypass pipe 100, and the processing gas storage container 20 can be directly exhausted by closing the valve V7 and opening the valve V12.

  The pulse CVI device of the present invention is configured as described above. Below, a process process is demonstrated based on Table 1. FIG.

  First, the to-be-processed object 43 is mounted on the sample stand 45 (STEP1), the reaction container 30 (STEP2), and the heating apparatus (STEP3) are set. See FIG. 3 for these procedures. Then, an argon gas pipe is connected (STEP 4).

  Next, the valves V8, V9, V11, V12, V13 are closed and the system is evacuated (STEP 5). After reaching a predetermined pressure, the heating device 50 is energized to heat the reaction vessel 30 (STEP 6). At the same time, the valve V13 is closed, the valve V1 is opened, argon gas is supplied to the space between the inner tube 31 and the outer tube 32 of the reaction vessel 30, and the valve V14 is further opened (STEP 7).

  Thereafter, the following operation is performed for cleaning the inside of the system. First, the valve V8 is closed and the valve V4 is opened to circulate hydrogen gas (STEP 8). Then, the valve V8 and the valve V12 are closed, and then the valve V7 is opened to supply hydrogen gas to the reaction vessel 30 (STEP 9). Thereafter, the valve V7 is closed, and the processing gas is held in the reaction vessel 30 for a predetermined time (STEP 10). After holding, the valve V8 is opened to evacuate the reaction vessel 30 (STEP 11). This process gas introduction (STEP 9) to exhaust (STEP 11) are repeated a predetermined number of times. After cleaning, the valve V4 is closed and the valve V7 is opened (STEP 13).

  Next, the following operation is performed to deposit on the workpiece 43. First, the valve V7 and the valve V8 are closed, the valve V12 is opened, the valve V3, the valve V4, the valve V5, and the valve V6 are opened, and each source gas is supplied to the processing gas storage container 20 (STEP 14). After the supply of the raw material gas is stabilized, the valve V12 is closed, and at the same time, the valve V7 is opened to supply the processing gas to the reaction vessel 30 (STEP 15). Thereafter, the valve V7 is closed and the processing gas is held in the reaction vessel 30 (STEP 16). The holding time is generally 0.2 to 10 seconds. After holding for a predetermined time, the valve V8 is opened to evacuate the reaction vessel 30 (STEP 17). The introduction of the processing gas (STEP 15) to the exhaust (STEP 17) are repeated a predetermined number of times to deposit silicon carbide on the workpiece 45. Then, the valve V3, the valve V4, the valve V5 and the valve V6 are closed, and the valve V7 is opened to complete the deposition process (STEP 19). The flow rate adjustment valve NV1 is adjusted in advance and fixed during processing.

  After completion of the deposition, the valves V7, V8, V9 and V11 are closed, the valves V4 and V12 are opened (STEP 20), the valve V12 is closed, the valves V7, V9 and V11 are opened, and hydrogen gas is supplied. The hydrogen gas is allowed to flow through the system (STEP 21), and then the valve V7 is closed to hold the hydrogen gas in the reaction part and the exhaust system for a predetermined time (STEP 22). After the holding, the valve V8 is opened and evacuation is performed (STEP 23). After repeating the evacuation (STEP 23) from the flow of hydrogen gas (STEP 21), the valve V4 is closed and the valve V7 is opened to complete the cleaning (STEP 25).

  Thereafter, the valve V7 is closed and the reaction vessel 30 is evacuated (STEP 26), then the valves V1 and V14 are closed and V13 is opened, and then the energization of the heating device 50 is stopped to cool the reaction vessel 30. Thereafter (STEP 27), the heating device 50 is lifted and separated from the reaction vessel 30 (STEP 28: see FIG. 3). After the separation, the valve V8 is closed and the valve V1, the valve V2, and the valve V7 are opened to fill the processing gas supply system with argon gas (STEP 29).

  After the above operation, removal of the argon tube (STEP 30), removal of the reaction vessel 30 (STEP 31), and removal of the workpiece 43 (STEP 32) are performed, and the series of deposition steps is completed. The valve opening / closing states in the above STEPs are shown in Table 1 (◯: open, x: closed), and the sequence is shown in FIG.

  In the above description, the valve V9 and the valve V11 are only operated and the valve V10 is closed when the reaction vessel 30 after deposition is exhausted. However, the exhaust is performed more efficiently by interlocking the valves V9 to V11. be able to. In this case, after the vacuuming in STEP 17, an operation of closing the valve V9 and the valve V11 and opening the valve V10 is added, and the same repeated operation including this additional vacuuming is performed. Table 2 shows the operation of a series of valves to which this additional evacuation is added. The above-described STEP 17 evacuation operation is “reaction vessel evacuation 1”, and the additional evacuation operation is “(STEP 18) reaction vessel”. Internal vacuuming 2 ”. FIG. 6 shows a sequence including this additional evacuation. The subsequent steps are the same as described above.

Tables 3 and 4 show the results of comparing the exhaust efficiency in the reaction vessel 30 with and without additional evacuation (bypass operation). Here, the processing gas storage container 20 has a capacity of 32 L, a reaction container 30 has a capacity of 9 L, an exhaust speed of 1200 L / min, a cycle of 3 seconds, an H ₂ gas flow rate of 25 l / min (converted to 0 ° C. standard state), and the exhaust gas storage container 60. The relationship between the exhaust time and the ultimate pressure of the reaction vessel 30 was determined for each volume. From Tables 3 and 4, it can be seen that the exhaust efficiency is significantly increased (several times to 20 times) by performing additional vacuuming.

  Hereinafter, the present invention will be further described with reference to examples.

An inner pipe 31 having an outer diameter of 170 mm, an inner diameter of 150 mm, and a length of 410 mm is produced using a mechanical carbon-made artificial isotropic graphite material (density 1.7 g / cm ³ ). In order to further suppress gas permeability, the inner pipe 31 is coated, impregnated and dried with a phenol resin (Phenolite J-325) manufactured by Dainippon Ink Chemical Co., Ltd. And heated to 1100 ° C. to clog the open pores with phenolic resin charcoal. Further, an outer tube 32 made of Inconel 601 having an outer diameter of 190 mm, an inner diameter of 180 mm, and a length of 560 mm is produced. The inner tube 31 and the outer tube 32 form a double reaction container 30. In order to obtain an airtight structure, a connection structure as shown in FIG. 2 is adopted. The internal volume of the reaction vessel 30 is about 9L.

  Further, a processing gas storage container 20 having a capacity of about 32L and an exhaust gas storage container 60 having a capacity of about 27L are prepared, and the reaction container 30, the processing gas storage container 20 and the exhaust gas storage container are connected by piping as shown in FIG. 60 is connected.

As the object to be treated 43, a carbonaceous sponge having a size of 80 × 80 × 40 mm and a pore diameter of about 1 mm (after impregnating, draining, and drying urethane foam with phenolite J-325, in a non-oxidizing atmosphere at 1000 ° C. The carbonized material is placed on the sample stage 45 of the reaction vessel 30. Then, SiCl ₄ , CH ₄ , H ₂ is used as a source gas, and Ar is used as a purge gas to deposit silicon carbide.

  First, the reaction vessel 30 is evacuated and heated to 1100 ° C. while flowing Ar gas at 1 L / min (converted to 0 ° C. standard state) in order to purge the inner tube 31 and the outer tube 32. Next, hydrogen gas is introduced into the reaction vessel 30 to clean the subject 43. About 100 pulses are introduced and exhausted as in the processing gas processing described later.

Next, in a state where the exhaust gas storage container 60, the reaction container 30, and the processing gas storage container 20 are evacuated, at a molar flow rate, H ₂ : 1.34 mol / min, CH ₄ : 0.6 mol / min, SiCl ₄ ; 0 Each raw material gas supply amount and the generation amount of SiCl ₄ are adjusted so as to be 6 mol / min. In addition, the opening degree of the flow rate adjustment valve NV1 (swagelok SS-8RS4) is set to a position opened about two rotations from the fully closed. This opening degree is a result of adjustment in a preliminary experiment so that the pressure of the bubbling tank does not fluctuate.

  In the deposition, first, the valve V7 is opened for 0.3 seconds with the valve V8 closed, and the processing gas retained in the processing gas storage container 20 is introduced into the reaction container 30 (STEP 15). Next, after closing the processing gas introduction valve V7, the exhaust valve V8 is opened for 2.1 seconds to exhaust the reaction vessel 30 (STEP 17). Next, the valve V7 is closed, and the reaction vessel 30 is kept sealed for 0.6 seconds (STEP 16). Next, it returns to STEP15. The process from STEP 15 to STEP 17 is defined as one pulse, and 3000 pulses are operated. The system pressure balance is achieved with about 100 pulses, and the pulse pressure in the reaction vessel 30 becomes a maximum pressure of 75 kPa abs and a minimum pressure of 10 kPa abs.

  After completion of the predetermined pulse operation, the cleaning operation with hydrogen gas was performed again for about 100 pulses, and then the reaction vessel 30 was cooled while being evacuated while being contained in the heating vessel 50. One hour later, when the temperature of the reaction vessel 30 decreased to 500 ° C., the heating device 50 was lifted and separated by the crane 55, and the reaction vessel 30 was continuously cooled. In about 1 hour, the temperature of the reaction vessel 30 dropped to about 80 ° C. For comparison, when cooling was performed without separating the heating device 50, it took about 6 hours to cool to about 80 ° C. That is, the cooling time was shortened by 4 hours by using the reaction vessel 30 having a double structure and separating the heating device 50.

When the to-be-processed object 43 was taken out and the deposit was investigated by the X ray diffraction method, it was (beta) -SiC. The deposition of SiC, bulk density 0.014 g / cm ³ before treatment was increased by 0.028 g / cm ^3.

  Further, 20 batches were operated under the same conditions, but no troubles such as corrosion of the outer tube 32 and destruction of the inner tube 31 occurred.

It is a figure which shows the structure of the pulse CVI apparatus which is 1 type of the vapor phase growth apparatus of this invention. It is sectional drawing which shows a reaction container. It is a figure for demonstrating the separation method of the reaction container and a heating apparatus. It is a figure which shows a trap mechanism. FIG. 7 is a sequence diagram showing the relationship between the operation timing of the processing gas introduction valve and the processing gas exhaust valve and the generated pressure when the bypass operation is not performed. It is a sequence diagram showing the relationship between the operation timing of the processing gas introduction valve and the processing gas exhaust valve when the bypass operation is performed, and the generated pressure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Process gas generator 11 Bubbling tank 20 Process gas storage container 30 Reaction container 40 Heating apparatus 43 To-be-processed object 45 Sample stand 60 Exhaust gas storage container 70 Vacuum pump 80 Trap mechanism 90 Exhaust gas processing apparatus 100 Bypass piping

Claims (11)

A reaction vessel, a heating device for heating and controlling an object to be processed disposed on a sample stage in the reaction vessel, a processing gas supply system for supplying a processing gas from a processing gas generation source into the reaction vessel, and an exhaust In a vapor phase growth apparatus comprising a pump and an exhaust system for controlling the inside of the reaction vessel to a reduced pressure and exhausting the reaction vessel,
The reaction vessel has a double tube structure composed of an inner tube and an outer tube, and a processing gas storage vessel for temporarily holding a processing gas is disposed between the reaction vessel and the processing gas generation source, and the reaction A vapor phase growth apparatus characterized in that an exhaust gas storage container for temporarily holding exhaust gas is disposed between the container and the vacuum pump.   The vapor phase growth apparatus according to claim 1, wherein a bypass pipe for bypassing the exhaust gas storage container is provided between a gas introduction pipe and a gas exhaust pipe of the exhaust gas storage container.   A space between the outer tube and the inner tube of the reaction vessel is kept airtight, a non-oxidizing gas supply system that supplies a non-oxidizing gas to the space, and a non-oxidizing gas is exhausted from the space. 3. The vapor phase growth apparatus according to claim 1, further comprising a non-oxidizing gas exhaust system.   The vapor phase growth apparatus according to any one of claims 1 to 3, wherein a trap mechanism filled with inorganic fibers is disposed between the reaction vessel and the exhaust gas storage vessel.   The abatement equipment is arranged at the rear stage of the exhaust pump, and the inner surface of a metal container provided in the abatement equipment is covered with a corrosion-resistant resin. Vapor growth equipment.   The vapor phase growth apparatus according to claim 1, further comprising a moving / separating unit that separates the heating device and the reaction vessel. In a vapor phase growth method in which an object to be treated is disposed in a reaction vessel, a process gas is tested while heating the reaction vessel, and a substance deposited by reaction of the treatment gas is vapor-phase grown on the object to be treated.
A first step of disposing the object to be processed in a reaction vessel having a double tube structure comprising an outer tube and an inner tube;
A second step of heating the object to be processed;
A third step of controlling the inside of the reaction vessel to a reduced pressure;
A fourth step of supplying a processing gas to the processing gas storage container in the reaction container and temporarily holding the processing gas;
A fifth step of supplying the processing gas from the processing gas storage container into the reaction container and temporarily holding the processing gas in the reaction container;
A sixth step of evacuating the reaction vessel and temporarily holding the exhaust gas in the exhaust gas storage vessel, and
A vapor phase growth method characterized in that an airtight space formed between the outer tube and the inner tube is maintained in a non-oxidizing gas atmosphere between the second step to the sixth step.   8. The vapor phase growth method according to claim 7, wherein the third to sixth steps are repeated.   The vapor phase growth method according to claim 7 or 8, further comprising a seventh step of exhausting the inside of the reaction vessel directly by a bypass pipe bypassing the exhaust gas storage vessel.   The vapor phase growth method according to claim 9, wherein the third to seventh steps are repeated.   The vapor phase growth method according to any one of claims 7 to 10, further comprising a step of separating the heating device and the reaction vessel after the treatment.

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