JPH0529225A - Vapor growth device - Google Patents

Abstract

PURPOSE:To prevent generation of irregularity of a thin film without lowering the operational efficiency of the title device by a method wherein etching gas is fed to a reaction furnace, and the adhered grown substance is removed by heating the adhered part. CONSTITUTION:A heater 41 is helically buried in a liner tube 15 provided in a reaction furnace. When the substance grown in a vapor growth operation is cleaned by etching, etching gas is fed from a gas introducing hole instead of raw gas. At this time, a heater 41 is heated up, the part, where a large quantity of grown substance is adhered to the inner wall of a liner tube 15, is heated up and the etching speed is made higher than in the other low temperature part. Accordingly, the grown substance adhered to the inner wall of the liner tube 15 can be removed quickly, and a thin film having no impurities can be obtained continuously without generation of irregularity on the formed thin film. Also, as the number of release of atmospheric air and deaeration is decreased, the operational efficiency of the title device can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth apparatus for vapor phase growing a compound semiconductor thin film on a crystal substrate.

[0002]

2. Description of the Related Art FIG. 4 shows a vapor phase growth apparatus 1 being developed by the present inventors. In the figure, the vapor phase growth apparatus 1 includes a cylindrical reaction furnace 7 in which an upper opening 3 is closed by a window body 5 to be in a hermetically sealed state and a source gas (monosilane gas, disilane gas, etc.) is supplied to the inside. A circular susceptor 11 disposed in the reaction furnace 7 on which a substrate 9 on which a thin film of a compound semiconductor is formed is placed, and an annular heater 13 disposed below the susceptor 11 to heat the susceptor 11. , A liner pipe 15 arranged on the bottom wall 7a of the reaction furnace 7 so as to cover the susceptor 11 and the heater 13, and a liner pipe 23 arranged so as to cover the upper part of the susceptor 11.
It consists of and.

At the bottom of the reaction furnace 7, a liner pipe 15 is provided.
A purge gas supply port 17 is connected to a space surrounded by, and an exhaust port 19 for discharging unnecessary gas in the reaction furnace 7 is provided. In addition, a raw material gas introduction port 21 through which the raw material gas is supplied into the reaction furnace 7 together with a carrier gas is formed in the upper portion of the reaction furnace 7, and a plurality of small holes are formed in the lower portion of the raw material gas introduction port 21. A straightening vane 35 is provided. A liner pipe 23 is arranged along the inner wall of the reaction furnace 7 so as to surround the space between the straightening plate 35 and the susceptor 11, and the liner pipe 23 supplies the raw material gas from the inlet 21 into the reaction furnace 7. The raw material gas is introduced into the susceptor 11 in a laminar flow.

The susceptor 11 is fixed to one end of a rotary shaft 29. The other end of the rotating shaft 29 penetrates the reaction furnace 7 and is supported by a vacuum seal bearing 27, and a pulley 37 is fixed to the tip end thereof. An endless belt 31 is wound around the pulley 37 and the drive shaft of the motor 33. As a result, the rotational driving force of the motor 33 is transmitted to the rotary shaft 29 via the belt 31, and the susceptor 11 is rotationally driven. Further, a reflection plate 25 is arranged below the heater 13 arranged below the susceptor 11, and reflects the heat of the heater 13 toward the lower part of the susceptor 11 to prevent heat dissipation. These susceptors 1
1, a liner pipe 15 is arranged so as to surround the heater 13, the reflection plate 25, and a purge gas (H ₂ , N ₂ ) is supplied from a purge gas supply port 17 into a space surrounded by the liner pipe 15.
Are being supplied.

To form a thin film of a compound semiconductor on the substrate 9 by the vapor phase growth apparatus, the source gas is supplied from the source gas inlet 21 into the reaction furnace 7 together with the carrier gas, and the heater 13 is energized. The susceptor 11 is heated to raise the substrate 9 to a predetermined temperature. At the same time, the motor 3
The rotational driving force of No. 3 is transmitted to the rotary shaft 29 via the belt 31 and the pulley 37, and the susceptor 11 is rotationally driven. The raw material gas supplied from the raw material gas inlet 21 into the reaction furnace 7 is
After passing through the small holes of the flow straightening plate 35, the flow is straightened as shown by the arrow in the drawing, and descends along the liner pipe 23 onto the surface of the susceptor 11.
By reacting on the substrate 9, a crystal thin film of a compound semiconductor is vapor-phase grown on the substrate 9. And unnecessary gas is exhausted 1
It is discharged from the reactor 9 to the outside of the reaction furnace 7. Liner tube 1
A purge gas is supplied from the purge gas supply port 17 to the inside surrounded by 5 to prevent the raw material gas from entering. Further, when cleaning the inside of the reaction furnace 7 by etching, an etching gas is supplied into the reaction furnace 7. However, by supplying the above-mentioned purge gas also during etching, the etching gas penetrates into the inside surrounded by the liner pipe 15. To prevent that.

[0006]

However, in the vapor phase growth apparatus 1, for example, the liner tube 1 is used during the vapor phase growth.
A high-temperature portion is generated on the inner and outer walls of 5 and the lower portion of the inner wall of the liner pipe 23. The product generated by the raw material gas adheres to the high temperature portion. When the attached product becomes thick, the product peels off from the inner wall when the pressure in the reaction furnace 7 fluctuates, drops onto the crystal substrate 9 and attaches, and gives a defect to the formed compound semiconductor.

In order to prevent this, the vapor phase growth apparatus 1 is disassembled, and the product attached to the inner wall is removed by a so-called wet method in which each part of the apparatus is washed with a solution.

However, in the removal of products by the above-mentioned wet method, since the inside of the reaction furnace 7 is once opened to the atmosphere and then deaerated, it takes time for cleaning and deaeration, and the operation efficiency of the apparatus is remarkably reduced. There is.

Further, the properties of the thin film formed before the disassembly cleaning of the device and the properties of the thin film formed after the disassembly cleaning of the device vary.

Therefore, an object of the present invention is to provide a vapor phase growth apparatus in which the operation efficiency of the apparatus does not decrease and the formed thin film does not vary.

[0011]

In order to achieve the above-mentioned object, in the invention described in claim 1, the etching gas is supplied into the reaction furnace so that the product adheres when the adhered product is removed. It is characterized in that a heating means for heating the operating portion is provided.

The invention according to claim 2 is characterized in that an attached product adhesion preventing means for preventing the adhesion of the product to the inner wall of the reaction furnace is provided.

[0013]

According to the first aspect of the invention, since the portion where the product adheres is heated during etching to increase the etching rate, the product can be efficiently removed.

According to the second aspect of the present invention, while the apparatus is operating to form the thin film on the substrate, the deposit adherence preventing means is used to deposit the product of the source gas on the inner wall of the reaction furnace. Adhesion is prevented.

[0015]

EXAMPLE Next, an example of the vapor phase growth apparatus of the present invention will be described with reference to FIGS. First Embodiment As shown in FIG. 1, a liner tube 1 arranged in a reaction furnace 7
A heater 41 (for example, a wire such as W or Mo, a thin plate, or carbon) is spirally embedded in the heater 5. The input terminal 43 of the heater 41 is connected to the liner tube 15
It is sealed above and below. Heater 41 and liner tube 15
In the gap 49 formed between the inner wall of the wire and the inner wall of the wire, a vacuum is maintained according to the oxidation resistance of the wire material, or the gap 4 is formed.
9 is filled with a reducing gas or the like. The heater 41 may be wound up and down in the axial direction of the liner tube 15, and the same effect can be obtained by winding it in the diameter direction of the liner tube 15.

In the vapor phase growth apparatus having the above structure, when etching the product produced during the vapor phase growth to clean it, an etching gas is supplied from the gas inlet instead of the source gas.

The heater 41 is heated at the time of etching to raise the temperature of a portion of the inner wall of the liner tube 15 where a large amount of product adheres, and accelerates the etching rate as compared with other portions having a low temperature. As a result, it is possible to etch a portion having a large amount of adhesion in a time equivalent to the etching time of the portion having a small amount of product adhesion.

According to the present embodiment, by heating the liner tube 15 with the heater 41, it is possible to rapidly remove (etch) the product attached to the inner wall of the liner tube 15. As a result, the number of times of disassembling the apparatus and cleaning each component is extremely reduced as in the prior art, so that the formed thin film does not vary, and a thin film without impurities can be continuously obtained. Moreover, since the number of times the atmosphere inside the reaction furnace 7 is released and the number of times of deaeration are reduced, the operating efficiency of the apparatus is improved.

Second Embodiment Next, a second embodiment will be described with reference to FIG. In the figure, a cooling jacket (water cooling) 45 is embedded in a portion of the inner wall of the reaction furnace 7 above the upper surface of the susceptor. Cooling water is supplied to the cooling jacket 45 from a cooling water supply device (not shown). The cooling jacket 45 cools the lower inner wall of the liner pipe 23 to lower the reaction temperature. The cooling method is the same as the above cooling jacket 4.
The cooling method is not limited to 5, and another cooling method may be used.

According to this embodiment, since the lower part of the inner wall of the liner tube 23 is cooled by the cooling jacket 45, the product does not adhere to the inner wall of the liner tube 23 during the vapor phase growth. Therefore, the number of times of disassembling and cleaning the apparatus is extremely reduced as compared with the conventional apparatus, so that the formed thin film does not vary and a thin film without impurities can be continuously obtained. In addition, the operating efficiency of the device is improved.

Further, according to this embodiment, the liner tube 2
Since the product does not adhere to the upper part of the inner wall of 3, the defect of the thin film due to the drop of the product on the thin film is eliminated, and a uniform compound semiconductor thin film can be obtained.

Third Embodiment Next, a third embodiment will be described with reference to FIG. In the figure, a plurality of nozzles 47 (however, only one nozzle 47 is shown in FIG. 3 and the others are omitted) are arranged along the circumferential direction of the lower portion of the inner wall of the liner pipe 23. The nozzle 47 penetrates the liner pipe 23 and the side wall of the reaction furnace 7,
It is connected to an etching gas supply device (not shown).
The height from the substrate 9 to the nozzle 47 is experimentally determined and set.

In this embodiment, in order to form a thin film of a compound semiconductor, while the source gas is being supplied from the source gas inlet 21 into the reaction furnace 7, the etching gas (chlorine or the like) is simultaneously supplied to the nozzle 47. Is discharged into the reaction furnace 7 and is discharged to the outside through the exhaust port 19. At this time, the source gas in the reaction furnace 7 becomes a laminar flow due to the rectifying plate 35 and flows toward the surface of the susceptor 11, so that the etching gas discharged from the nozzle 47 spreads to the central portion of the reaction furnace 7. It is suppressed. As a result, the etching gas discharged from the nozzle 47 flows downward along the inner wall of the liner pipe 23 and etches only the product attached to the inner wall of the liner pipe 23. As described above, in this embodiment, a thin film can be formed on the substrate 9 while etching the adhesion on the inner wall of the liner tube 23.

According to this embodiment, since the etching gas is discharged from the nozzle 47 along the inner wall of the liner tube 23, the product does not adhere to the inner wall of the liner tube 23, which is a comparison with the conventional apparatus. Since the number of times of disassembling and cleaning the device is extremely reduced, the formed thin film does not vary, and a thin film without impurities can be continuously obtained. In addition, the operating efficiency of the device is improved.

Further, according to this embodiment, the liner tube 2
Since the product does not adhere to the inner wall of 3, the defect of the thin film due to the drop of the product on the thin film is eliminated, and a homogeneous compound semiconductor thin film can be obtained on the substrate 9.

In this embodiment, the liner tubes 15 and 23 are
Although the description has been made on the removal of the product adhering to, the present invention is not limited to this. That is, in the above embodiment, the vapor phase growth apparatus provided with the liner tubes 15 and 23 was described as an example. However, even in a general vapor phase growth apparatus in which the liner tubes 15 and 23 are not provided, the etching rate is It can be carried out by embedding a heater for accelerating in the vicinity of the wall of the reaction vessel to which the product tends to adhere. According to the present invention, the product can be prevented from adhering to any place on the inner wall of the reaction furnace. Further, in the above three embodiments, the susceptor is of a rotating type, but the present invention is not particularly limited to the case where the susceptor rotates.

[0027]

As described above, according to the vapor phase growth apparatus of the present invention, it is possible to obtain an excellent effect that the operation efficiency of the apparatus does not decrease and the formed thin film does not vary. To be

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a liner tube of a vapor phase growth apparatus according to a first embodiment.

FIG. 2 is a sectional view showing a vapor phase growth apparatus according to a second embodiment.

FIG. 3 is a sectional view showing a vapor phase growth apparatus according to a third embodiment.

FIG. 4 is a cross-sectional view showing a conventional vapor phase growth apparatus.

[Explanation of symbols]

1 Vapor growth equipment 7 Reactor 11 susceptor 15,23 Liner tube 41 heater 45 cooling jacket 47 nozzles

Claims (2)

[Claims] 1. A vapor phase growth apparatus comprising a reaction furnace to which a source gas is supplied, a susceptor arranged in the reaction furnace, and a first heating means for heating the susceptor,
Supply means for supplying an etching gas into the reaction furnace to remove the product adhered in the reaction furnace; and second heating means for heating the vicinity of the portion where the product adheres during etching. A vapor phase growth apparatus characterized by being provided. 2. A vapor phase growth apparatus comprising a reaction furnace to which a raw material gas is supplied, a susceptor arranged in the reaction furnace, and heating means for heating the susceptor. A vapor phase growth apparatus comprising a product adhesion preventing means for preventing the adhesion of products.