JP2004241412A - Vapor phase epitaxial growth system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase epitaxial growth system in which the flow rate of material gas can be made substantially uniform over the entire width of a substrate even when a reaction tube is slightly wider than the substrate or a substrate holder. <P>SOLUTION: The vapor phase epitaxial growth system comprises a material gas introduction pipe 11, the reaction tube 21 connected with the material gas introduction pipe 11, an exhaust pipe 31 for exhausting reacted gas connected with the reaction tube 21, and a substrate support 42 for holding the substrate 41 on the substantially same plane as the lower inner wall face 22 of the reaction tube 21. A pair of partition plates 32 are provided in the exhaust pipe 31 in order to separate the exhaust pipe 31 into a side wall side exhaust pipe 33 and a central exhaust pipe 34. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vapor phase growth apparatus for growing a compound on a substrate by flowing a source gas over the substrate.
[0002]
[Prior art]
Conventionally, metal organic chemical vapor deposition has been used as a method for growing a compound semiconductor crystal. The metalorganic vapor phase epitaxy is excellent in mass productivity and production of high-quality devices, and various vapor phase epitaxy apparatuses used for it have been developed.
[0003]
In a conventional vapor phase epitaxy apparatus, as shown in FIG. 5, a substrate support (susceptor) 102 for supporting a substrate 101 is provided inside a reaction tube 103 arranged substantially horizontally for flowing a source gas. A substrate 101 was placed on a body 102, and a source gas was flowed in parallel with a growth surface of the substrate 101 to form a thin film on the surface of the substrate 101. In this case, as indicated by the arrows in FIG. The flow velocity of the raw material gas becomes highest near the center, and the flow velocity of the raw material gas becomes lower as it moves toward the side wall. For this reason, there is a problem that the thickness of the thin film grown by the vapor phase becomes non-uniform in the vicinity of the center and the outer periphery of the substrate 101.
[0004]
In order to solve this conventional disadvantage, for example, in a vapor phase growth apparatus described in Patent Document 1, a method of solving the problem is to make the surface of the side wall 110 of the reaction tube 103 uneven as shown in FIG. Has been. By making the surface of the side wall 110 uneven, the vicinity of the side wall 110 becomes turbulent, and the flow velocity of the source gas on the substrate 101 can be made uniform as shown in FIG.
[0005]
[Patent Document 1]
Japanese Patent No. 3127501 (Page 3, FIG. 1 and FIG. 2)
[0006]
[Problems to be solved by the invention]
In the vapor phase growth apparatus described in Patent Document 1, near the center of the reaction tube 103, the flow rate of the source gas is uniform. Therefore, it is effective when the width of the reaction tube 103 is relatively large with respect to the substrate 101 and the substrate support 102. However, if the width of the reaction tube 103 is large, a large amount of source gas must be flowed during film formation, and a large amount of the source gas is exhausted without being used for the reaction, resulting in waste and an increase in element cost. Was the cause. In order to eliminate this waste, it is required that the width of the reaction tube 103 be as narrow as possible.
[0007]
However, in the vapor phase growth apparatus described in Patent Literature 1, the flow rate of the source gas is slow near the side wall 110 and rapidly increases as going from the side wall to the inside. In the vapor phase growth apparatus described in Patent Document 1, when the narrow reaction tube 103 is configured such that the width of the reaction tube 103 is slightly larger than the width of the substrate 101 and the substrate holder 102 as shown in FIG. The outer peripheral portion of the substrate 101 is located in a region where the flow velocity is not uniform. As shown in FIG. 7, the flow velocity V2 of the source gas at the outer peripheral portion of the substrate 101 is smaller than the flow velocity V1 at the central portion of the substrate 101, and the outer peripheral portion of the substrate 101 is located in the region of the flow velocity V2. As a result, the film thickness after the film formation was uneven at the central portion and the outer peripheral portion of the substrate 101.
[0008]
Therefore, the present invention has been made to solve the above-mentioned problem, and the source gas is supplied over the entire width of the substrate even when the width of the reaction tube is slightly larger than the width of the substrate or the substrate holder. It is an object of the present invention to provide a vapor phase growth apparatus capable of making the flow velocity of the gas phase substantially uniform.
[0009]
[Means for Solving the Problems]
According to a certain aspect of the vapor phase growth apparatus based on the present invention, a source gas introduction tube, a reaction tube connected to the source gas introduction tube, and an exhaust tube connected to the reaction tube and discharging a reacted gas. And a substrate support for holding a substrate substantially flush with the upper or lower inner wall surface of the reaction tube, wherein the exhaust pipe has a substantially uniform flow rate of the source gas on the substrate. For this purpose, a flow rate control means for controlling the flow rate of the source gas flowing on the substrate is provided.
[0010]
According to the above-mentioned vapor phase growth apparatus, since the flow rate of the source gas on the substrate is kept uniform by controlling the discharge of the reacted gas, the compound can be uniformly deposited on the substrate surface.
[0011]
According to another aspect of the vapor phase growth apparatus based on the present invention, a source gas introduction pipe, a reaction pipe connected to the source gas introduction pipe, and an exhaust pipe connected to the reaction pipe to discharge a reacted gas And a substrate support for holding a substrate substantially flush with the upper or lower inner wall surface of the reaction tube, wherein the exhaust pipe is used to remove reacted gas mainly near both side walls. It is separated into a side wall exhaust pipe for discharging and a central exhaust pipe for discharging reacted gas mainly near the center.
[0012]
According to the vapor-phase growth apparatus, the exhaust pipe is separated into a side wall-side exhaust pipe that mainly discharges the reacted gas near both side walls and a central exhaust pipe that mainly discharges the reacted gas near the center. Therefore, the flow rates of the reacted gas discharged from the side wall side exhaust pipe and the reacted gas discharged from the central exhaust pipe can be controlled. Thus, even when the width of the reaction tube is slightly wider than the substrate, the flow rate of the source gas flowing on the substrate can be made uniform, and the compound can be deposited uniformly on the substrate surface.
[0013]
In the vapor phase growth apparatus, preferably, a pair of partition plates are provided inside the exhaust pipe, and the exhaust pipe is separated by the partition plate to form the side wall side exhaust pipe and the central exhaust pipe. . According to this configuration, the exhaust pipe can be separated into three paths with a simple configuration.
[0014]
Preferably, in the vapor phase growth apparatus, pumps of different systems are respectively connected to the side wall side exhaust pipe and the central exhaust pipe. According to this configuration, by controlling the operation of the pump connected to the side wall side exhaust pipe and the central exhaust pipe, the flow rate of the source gas flowing on the substrate can be made uniform.
[0015]
According to another aspect of the vapor phase growth apparatus based on the present invention, a source gas introduction pipe, a reaction pipe connected to the source gas introduction pipe, and an exhaust pipe connected to the reaction pipe to discharge a reacted gas And a substrate support for holding a substrate in substantially the same plane as the upper or lower inner wall surface of the reaction tube, wherein a mesh body having a plurality of openings formed in the exhaust pipe is provided. The area of the opening per unit area of the net is larger on the side walls than on the center.
[0016]
According to the vapor phase growth apparatus, the exhaust pipe is provided with a mesh having a plurality of openings formed therein, and the area of the openings per unit area of the mesh is larger on both side walls than in the center. As a result, the flow path resistance is larger in the central portion than in the vicinity of the side wall. By setting the flow rate of the reacted gas discharged from the vicinity of the side wall to be higher than the flow rate of the reacted gas discharged from the central portion, the flow rate of the source gas flowing on the substrate can be controlled. Thus, even when the width of the reaction tube is slightly wider than the substrate, the flow rate of the source gas flowing on the substrate can be made uniform, and the compound can be deposited uniformly on the substrate surface.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the vapor phase growth apparatus according to the present embodiment will be described with reference to the drawings.
[0018]
(Embodiment 1)
Hereinafter, the vapor phase growth apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a horizontal sectional view showing the structure of the vapor phase growth apparatus in the present embodiment, and FIG. 2 is a vertical sectional view showing a II-II section in FIG.
[0019]
(Structure of vapor phase growth equipment)
The structure of the vapor phase growth apparatus will be described with reference to FIG. The vapor phase growth apparatus according to the present embodiment includes a source gas introduction pipe 11, a reaction pipe 21 connected to the source gas introduction pipe 11, an exhaust pipe 31 connected to the reaction pipe 21, and discharging a reacted gas. A substrate support 42 for holding the substrate 41 on substantially the same plane as the lower inner wall surface 22 of the tube 21 is provided.
[0020]
As shown in FIGS. 1 and 2, the reaction tube 21 is formed in a cylindrical shape having a substantially rectangular cross section so as to form a flat space through which the raw material gas flows. A circular opening is formed in the lower inner wall surface 22 of the reaction tube 21, and a circular substrate support 42 for holding the substrate 41 is provided in the opening. The substrate support 42 is fitted and attached to an upper surface of a housing 44 supported by a rotating shaft 43. A heater 45 is provided inside the housing 44, and can heat the substrate 41 via the substrate support 42. The surface of the substrate 41 supported by the substrate support 42 is held horizontally so as to be located on substantially the same plane as the lower inner wall surface 22 of the reaction tube 21.
[0021]
The source gas introduction pipe 11 is configured to have a rectangular cross section, and is configured such that its width increases from the gas introduction port 12 toward the reaction tube 21. A source gas supply device (not shown) is connected to the gas inlet 12.
[0022]
The exhaust pipe 31 is configured to have a rectangular cross section, and is configured such that its width becomes smaller as going from the upstream side to the downstream side. A pair of partition plates 32, 32 as shown in FIG. 1 are provided inside the exhaust pipe 31, and the inside of the exhaust pipe 31 is connected to sidewall exhaust pipes 33, 33 located on both side walls, and a central exhaust pipe. The tube 34 is divided into three parts.
[0023]
As is clear from FIG. 1, the side wall side exhaust pipe 33 has substantially the same width from its upstream side to its downstream side. On the other hand, the central exhaust pipe 34 is configured such that its width becomes smaller as going from the upstream side to the downstream side. The end of the partition plate 32 on the reaction tube 21 side is formed in a wedge shape so that the reacted gas flows smoothly.
[0024]
Pumps P1 and P2 are connected to the side wall side exhaust pipe 33 and the central exhaust pipe 34, respectively. As shown by the arrows in FIG. 1, the pumps P1 and P2 are arranged so that the flow rate of the reacted gas in the exhaust pipes 33 on both side walls near the inlet of the exhaust pipe 31 is higher than the flow rate of the reacted gas in the central exhaust pipe 34. Each ability is set.
[0025]
(Action / Effect)
A source gas such as TMG, TMA, or AsH ₃ is introduced into the gas inlet 12 together with a carrier gas such as hydrogen, and merges before the substrate 41, and the merged gas flows on the substrate 41. It rotates with the substrate support 42 and is heated by the heater 45. When the source gas flows on the heated substrate 41, the reaction surface on the surface of the substrate 41 reacts to form a film on the substrate 41. The source gas that has passed over the substrate 41 becomes a reacted gas and is absorbed by the exhaust pipe 31.
[0026]
In the conventional vapor phase growth apparatus, the flow rate of the source gas is high near the center of the reaction tube, and the flow rate is low on both side walls. However, in the present embodiment, since the exhaust pipe 31 is configured as described above, near the inlet of the exhaust pipe 31, the flow rate of the reacted gas in the both-side exhaust pipe 33 is reduced by the central exhaust pipe 34. It becomes larger than the flow rate of the reacted gas. As a result, in the reaction tube 21, the flow rate of the raw material gas is increased near the both side walls as compared with the related art. At each of a, b, c, and d shown in FIG. 1, the flow rate of b is slightly lower than a, and at c, it is drawn by the side wall exhaust pipe 33 and slightly turns to the side wall. This does not affect the thickness of the film, and the flow rate of the source gas on the substrate 41 becomes substantially uniform. As a result, a film having a uniform thickness can be formed on the surface of the substrate 41.
[0027]
In the present embodiment, the exhaust pipe 31 is divided into three, but may be divided more finely for more precise control. Further, in the present embodiment, the exhaust pipe 31 is divided into three by forming the partition plate 32, but the exhaust pipe 31 may be formed of three completely independent pipes.
[0028]
(Embodiment 2)
Next, with respect to different embodiments of the present invention, only matters different from the above embodiments will be described. FIG. 3 is a horizontal sectional view showing the structure of the vapor phase growth apparatus according to the present embodiment, and FIG. 4 is a longitudinal sectional view showing the IV-IV section of FIG.
[0029]
(Structure of vapor phase growth equipment)
In the present embodiment, a mesh 51 provided with a large number of openings 52 is provided near the inlet of the exhaust pipe 31. As shown in FIG. 4, the openings 52 provided in the net-like body 51 are arranged such that the area of the openings 52 per unit area is larger on both side wall sides S than on the central part C. In the present embodiment, a large number of openings 52 having the same shape are provided, but the number of openings 52 provided per unit area is reduced in the central portion C and increased in the side walls S. A pump P is connected downstream of the exhaust pipe 31 to suck the entire exhaust pipe 31.
[0030]
(Action / Effect)
Since the reticulated body 51 as described above is provided, when the reacted gas passes through the reticulated body 51, the resistance at the central portion C becomes larger than the resistance at the side walls S. As shown by the arrow in FIG. 3, at the inlet of the exhaust pipe 31, the flow rate at the side walls S is larger than the flow rate at the central portion C. Due to the influence, the flow velocity of the raw material gas flowing on the surface of the substrate 41 is more greatly reduced in the central portion than in the side walls. In the conventional vapor phase growth apparatus, the flow rate of the source gas is high near the center and slow near the side walls. However, the flow rate of the source gas is offset by the above-mentioned effects, and becomes substantially uniform on the surface of the substrate 41.
[0031]
In the present embodiment, a plurality of openings 52 having the same shape are provided in the mesh body 51 and the number thereof is changed. However, the shape and size of the openings may be changed. Further, in the present embodiment, the net-like body 51 is divided into two areas of the central part C and the side walls S, and the area of the opening 52 per unit area is changed respectively. May be configured such that the opening area gradually increases from the side to the side wall portion.
[0032]
In the above two embodiments, the so-called face-up case where the reaction surface of the substrate 41 faces upward is described. However, the substrate support 42 is provided on the upper inner wall surface side of the reaction tube 21, and the substrate 41 Needless to say, the present invention can be applied to a so-called face-down case in which the reaction surface is attached so as to face downward.
[0033]
It should be noted that the above-described embodiment disclosed herein is merely an example in all respects, and is not a basis for restrictive interpretation. Therefore, the technical scope of the present invention is not defined only by the above-described embodiments, but is defined based on the description of the claims. In addition, all changes within the meaning and scope equivalent to the claims are included.
[0034]
【The invention's effect】
According to the present invention, even when the width of the reaction tube is slightly larger than the width of the substrate or the substrate holder, the flow rate of the source gas can be made substantially uniform over the entire width of the substrate, Waste can be reduced.
[Brief description of the drawings]
FIG. 1 is a horizontal sectional view showing a structure of a vapor phase growth apparatus according to a first embodiment based on the present invention.
FIG. 2 is a longitudinal sectional view showing a section taken along line II-II in FIG.
FIG. 3 is a horizontal sectional view showing a structure of a vapor phase growth apparatus according to a second embodiment based on the present invention.
FIG. 4 is a longitudinal sectional view showing a section taken along line IV-IV in FIG. 3;
FIG. 5 is a horizontal sectional view showing the structure of a conventional vapor phase growth apparatus.
FIG. 6 is a horizontal sectional view showing the structure of a conventional vapor phase growth apparatus.
FIG. 7 is a horizontal sectional view showing a structure of a conventional vapor phase growth apparatus.
[Explanation of symbols]
Reference Signs List 11 raw material gas introduction pipe, 12 gas introduction port, 21 reaction pipe, 31 exhaust pipe, 32 partition plate, 33 side wall exhaust pipe, 34 central exhaust pipe, 41 substrate, 42 substrate support, 51 mesh body, 52 opening, P1, P2 pump.

Claims (5)

A source gas introduction pipe, a reaction pipe connected to the source gas introduction pipe, an exhaust pipe connected to the reaction pipe to discharge reacted gas, and an upper or lower inner wall surface substantially flush with the reaction tube. And a substrate support for holding the substrate,
A vapor phase growth apparatus, wherein the exhaust pipe is provided with flow rate control means for controlling the flow rate of the source gas flowing on the substrate in order to make the flow rate of the source gas on the substrate substantially uniform. A source gas introduction pipe, a reaction pipe connected to the source gas introduction pipe, an exhaust pipe connected to the reaction pipe to discharge a reacted gas, and a plane substantially flush with an upper inner wall surface or a lower inner wall surface of the reaction tube. And a substrate support for holding the substrate,
Wherein the exhaust pipe is separated into a side wall exhaust pipe mainly for discharging reacted gas near both side walls and a central exhaust pipe mainly for discharging reacted gas near a central portion. apparatus. The vapor phase growth apparatus according to claim 2, wherein a pair of partition plates are provided inside the exhaust pipe, and the exhaust pipe is separated by the partition plate to form the side wall-side exhaust pipe and the central exhaust pipe. . 4. The vapor phase growth apparatus according to claim 2, wherein pumps of different systems are connected to the side wall side exhaust pipe and the central exhaust pipe, respectively. 5. A source gas introduction pipe, a reaction pipe connected to the source gas introduction pipe, an exhaust pipe connected to the reaction pipe to discharge a reacted gas, and a plane substantially flush with an upper inner wall surface or a lower inner wall surface of the reaction tube. And a substrate support for holding the substrate,
A gas-phase growth apparatus, wherein a net-like body having a plurality of openings formed in the exhaust pipe is provided, and the area of the openings per unit area of the net-like body is larger on both side walls than in the center.

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