JPS6254081A - Vapor growth device - Google Patents

Abstract

PURPOSE:To prevent the deposition of the vapor phase reaction product on the inner face of an inner bell jar by spouting a cooling fluid in the specified shapes into a clearance between the inner bell jar and an outer bell jar in the title vapor growth device and increasing the cooling effect on the inner bell jar. CONSTITUTION:A reaction chamber 3 is composed of a stainless steel outer bell jar 4, a quartz inner bell jar 2 and a stainless steel base plate 1. A wafer 10 is placed in the chamber 3, a gaseous semiconductor material such as SiCl4 is supplied from the nozzle 12 of a hollow rotating shaft 11 and an Si semiconductor layer is formed on the surface of the wafer 10 by the thermal decomposition of the SiCl4. In this case, many nozzle holes 28 are provided on the nozzle 20 of a cooling fluid supply device fixed to the outer bell jar 4 to prevent the deposition of the Si semiconductor on the inner face of the inner bell jar 2, a cooling fluid such as air is spouted at high pressure at a small acute angle of alpha to the outer face of the inner bell jar to sufficiently cool the inner bell jar 2 and the thermal decomposition of the SiCl4 on the inner face of the inner bell jar 2 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vapor phase growth apparatus, and particularly relates to a cylindrical or bell-shaped quartz member forming a reaction chamber. The present invention relates to effective cooling of the inner wall in a vapor phase growth apparatus in which the inner wall is cooled by flowing a cooling fluid between the quartz member that is the wall and the outer wall.

[Prior art]

For example, in a vertical vapor phase growth apparatus, as shown in FIG. 2, a reaction chamber 3 is formed by a base plate 1 made of stainless steel and an inner bell jar 2 made of quartz, and the outside of the bell jar 2 is covered with an outer bell jar 4 made of stainless steel. The outer bell jar 4 is cooled by flowing cooling water into a jacket (not shown), and a cooling fluid such as N2 gas or air is supplied from a cooling fluid supply port 5 provided at the top of the outer bell jar 4. By exhausting air from a plurality of exhaust ports 6 provided near the bottom of the belljar 4, a cooling fluid flows into the gap 7 between the two belljars 2 and 4, thereby cooling the inner belljar 2.

In addition, in FIG. 2, 8 is a susceptor, 9 is a work coil, 10 is a wafer, 11 is a hollow rotating shaft, 12 is a nozzle,
13 is an exhaust port, 14 is an observation window, and 15 is a photosensor for controlling the temperature of the susceptor 8. The work coil 9 heats the susceptor 8 and the wafer 10, and the semiconductor material gas is ejected from the nozzle 12. A semiconductor crystal is grown on the surface of 10.

The inner bell jar 2 is cooled by the cooling fluid from the cooling fluid supply port 5. When the inner bell jar 2 reaches a high temperature, the semiconductor material gas is supplied from the nozzle 12 into the reaction chamber 3 and causes thermal decomposition on the inner surface of the inner bell jar 2. This is done to prevent the product from getting stuck.

By the way, since the gap 7 is relatively narrow, conventionally, the cooling fluid supply port 5t is simply a hole that opens to the gap 7, as shown in FIG. The fluid was supplied to create a flow of cooling fluid within the gap 7, thereby cooling the inch bell jar 2.

[Problems to be Solved by the Invention] However, when the cooling fluid supply port 5 is made into a simple hole, 60t/11i/R of N2 gas is allowed to flow and N2 gas, which is a semiconductor material gas with a relatively high decomposition temperature, is used. Even if silicon chloride (SiC64) is used, silicon will adhere to the inner surface of the top of the inner bellger 2 if the vapor phase growth apparatus is used for a long time, such as one hour.

The attached silicon completely absorbs the infrared rays emitted from the susceptor 8, so its temperature rises and polysilico/ is produced.

This polysilicon is generated quickly and spreads over the top surface of the inner bellger 2, making it impossible to measure the temperature with the photosensor 15, or falling and adhering to the sea urchin 10 during vapor phase growth, inducing crystal defects. This causes various problems. The polysilicon is removed by gas etching with hydrogen chloride or cleaning with a mixture of boiling acid and nitric acid, but productivity decreases due to this removal, and cleaning with the mixture requires proper concentration control. If this is not done, problems such as devitrification of the quartz will occur, so it is necessary to suppress the adhesion of the semiconductor material to the inner belljar 2 as much as possible. For this purpose, the flow rate of the cooling fluid supplied to the gap 7 may be increased to keep the inner bellger 2 at a lower temperature, but this increases running costs and also causes the gap 7 to communicate with the reaction chamber 3. In a vapor phase growth apparatus with a structure of 1
This has a negative effect on the flow of the semiconductor material gas in the reaction chamber 3, so there is a problem that there is a limit to the increase in the supply flow rate.

[Defined means of solving problems]

In the present invention, at least a part of one reaction chamber has a double wall structure consisting of bell-shaped or cylindrical members such as the above-mentioned inner bell jar and outer bell jar.

In a vapor phase growth apparatus in which a cold 1iIθ1 body is flowed between the double walls to cool the inner wall, the cooling fluid supply port between the double walls is formed into a nozzle shape, and the cooling fluid is injected. It is something.

[Effect]

In the present invention, since the cooling fluid is injected between the double walls from the nozzle-shaped cooling fluid supply port, the cooling fluid can flow over a wider area at a relatively high speed without increasing the flow rate of the cooling fluid. The inner wall is effectively cooled.

〔Example〕

FIG. 1 showing one embodiment of the present invention will be described below.

2 is an inner bell jar made of quartz, which is the same as the inner bell jar 2 shown in FIG. 2, and 4 is a cooling fluid nozzle 2o, which will be described later.
The outer belljar 4 is the same as the outer belljar 4 shown in FIG. 2, except that the attachment part is different.

A flange 22 having a hole 21 is provided at the top of the outer bell jar 4 . The cooling fluid nozzle 20 is mounted on the flange 22 with a presser plate 23. It is attached with bolts 24. An O cylinder 25 is provided between the cooling fluid nozzle 2o and the flange 22. Cooling fluid nozzle 20
has a flow path 26, the base end of which is connected to a cooling fluid supply source (not shown) via a hose 27. The tip of the cooling fluid nozzle 20 is formed into a conical shape, and a plurality of nozzle holes 28 are radially opened from the flow path 26 to the conical surface of the tip. These nozzle holes 28 are set so that the total cross-sectional area of the flow passages is smaller than the cross-sectional area of the flow passages 26, and by applying pressure to the cooling fluid supply source,
Cooling fluid is injected from the nozzle hole 28 at a relatively high speed.

Said nozzle holes 28 are oriented at a relatively small acute angle α with respect to the outer surface of the inner bell jar 2 to bring the cooling fluid into positive contact with the outer surface of the inner bell jar 2 and to allow it to slide over this outer surface. It is.

Since this device is configured as described above, the cooling fluid is vigorously injected from the nozzle hole 28 as shown by the symbol F.
It flows further within the gap 7 at high speed, increasing the degree of contact with the inner bellger 2 and increasing heat exchange efficiency. Because the range in which the cooling fluid flows at high speed is expanded, the range in which heat exchange can take place effectively is expanded. In order to prevent the cooling fluid from each nozzle hole 28 from coming into too strong contact with each other, it is preferable to determine the number of nozzle holes 28 in consideration of the opening angle of the injection. Even when flowing from the nape to the entire circumference, about 4 pieces are sufficient.

Next, in order to clarify the effects of the present invention, experimental results regarding the flow of cooling fluid conducted using a conventional device and a device according to the present invention will be shown.

In the conventional device, the diameter of the cooling fluid supply port 5 shown in FIG. L/mM.

On the other hand, in the device of the present invention, the diameter 14 of the nozzle hole 28
mm, four are equally spaced, the angle α is approximately 37°, the same N2 gas is used as the cooling fluid, and the flow rate is 50 L/1.
rits. Note that both conditions are exactly the same except for the above conditions.

On the outer surface of the inner bell jar 2, as shown in FIG. When the state of fluid flow was investigated, the range in which the tuft 30 was observed to fall in the conventional device was within the range shown in Fig. 4, whereas in the device of the present invention, the range where the tuft 30 was observed to fall was as large as the range B. It was confirmed that the area had been expanded to a wide area, and that it covered almost the entire area above Inner Belljar 2.

The semiconductor material gas was chlorine tetrachloride, the vapor phase growth time was 08 μm/ln; ts, and the time for one vapor phase growth was f.
60 m, and when vapor phase growth was actually carried out using the conventional apparatus described above and the apparatus of the present invention, polysilicon was deposited on the inner surface of the top of the inner bellger 2 with the conventional apparatus, and the usability limit was reached at about 20 charges. On the other hand, in the apparatus of the present invention, almost no generation of polynoricone, which causes devitrification, was observed even after 40 charges were continued.

Although the above-mentioned embodiment shows an example in which the present invention is applied to a vertical vapor phase growth apparatus, the present invention is not limited to this, and can be applied to other types such as a horizontal type and a barrel type in which the reaction chamber is formed of a double cylindrical member. The present invention can also be applied to a vapor phase growth apparatus, and it is preferable that the installation position and number of cooling fluid nozzles 20 are appropriately set based on the relationship between the shape of the double-walled structure and the location that requires strong cooling.

〔Effect of the invention〕

As described above, according to the present invention, the inner wall of the reaction chamber can be effectively cooled over a wide range with a relatively small flow rate of cooling fluid, thereby greatly reducing the adhesion of semiconductor material to the surface of the reaction chamber. This makes it possible to achieve higher quality vapor phase growth and improve productivity.
), it is possible to obtain effects such as facilitating the use of semiconductor material gases such as

[Brief explanation of drawings]

Fig. 1 is a partially enlarged sectional view showing the main parts of an embodiment of the present invention, Fig. 2 is a schematic sectional view showing an example of a conventional device, and Fig. 3 is a tuft used to observe the flow of cooling fluid. FIG. 4 is a partially enlarged cross-sectional view showing the strength of the flow of cooling fluid in the conventional device and the device of the present invention. 2...Inner wall (inner bell jar), 3...Reaction chamber. 4... Outer wall (outer bell jar), 20... Cooling fluid nozzle, 28... Nozzle hole, 30... Tuft.

Claims (1)

[Claims] 1. In a vapor phase growth apparatus in which at least a part of the reaction chamber has a double wall structure, and a cooling fluid is flowed between the double walls to cool the inner wall. A vapor phase growth apparatus characterized in that the cooling fluid supply port is shaped like a nozzle and the cooling fluid is injected. 2. The vapor phase growth apparatus according to claim 1, wherein the nozzle-shaped cooling fluid supply port is oriented at an acute angle with respect to the inner wall surface. 3. Claim 1 or 2, characterized in that a plurality of nozzle-shaped cooling fluid supply ports are provided radially.
Vapor phase growth apparatus described in Section 1.