JPH0594956A - Vapor growth device and vapor growth method therewith - Google Patents

Abstract

PURPOSE:To provide a vapor growth device where a thin film excellent in interface sharpness can be made to grow decreasing dummy lines in number, and block valve lines are lessened in number. CONSTITUTION:Gas supply lines A70, B71, and C72 are composed of AsH3 process lines A62, B65, and C68, and balance lines A61, B64, and C67. The gas supply lines A70, B71, C72, and a dummy line 62 become equal in viscosity flow-rate product through the balance lines A61, B64, and C67. When a film is formed, only the dummy line 62 is connected to a main line only while the gas of AsH3 (A), AsH3 (B), and AsH3 (C) is not used, whereby a vapor crystal growth device where a main line 1 is not changed in gas pressure with a single dummy line can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Since the present invention corresponds to a plurality of process gas lines with a single dummy line, the number of valves to be opened and closed when materials of different compositions are stacked is reduced by half, and switching of valves is possible. By suppressing the accompanying pressure fluctuations in the main line, it is possible to form an ultra-thin film with excellent interface steepness, and by significantly reducing the number of expensive block valves, it is inexpensive and the device configuration is simple,
The present invention relates to a vapor phase growth apparatus that realizes the formation of an ultrathin film having extremely stable crystallinity and excellent interface steepness, and a vapor phase growth method using the same.

[0002]

2. Description of the Related Art The structure of a conventional crystal growth apparatus is shown in FIG.
(Suematsu et al., Journal of Crystal Growth J.Cryst. Growth, 9
3,353 (1988)). 1 is a main line for supplying the raw material gas to the crystal growth chamber, 2 is a vent line for discharging a gas not necessary for crystal growth, and 4, 6, 8, 10, 12, and 14 are gas flows to the main line 1. Control the air valve,
5, 7, 9, 11, 13, 13 and 15 are gas vent lines 2
Valve to control the flow to, 20, 22, 23, 2
5, 26, 28 have gas flow rates of 100, 100, 180,
A mass flow controller for controlling 180, 90, 90 ccm, 62 is a process gas line for supplying the gas of A, gas line A, 60 is a dummy line A for supplying hydrogen having the same flow rate as gas line A, and 65 is for B. Gas line B, 63, which is a process gas line for supplying gas
Is a dummy line B for supplying hydrogen having the same flow rate as the gas line B, 68 is a gas line C which is a process gas line for supplying the gas of C, and 66 is a dummy line C for supplying hydrogen having the same flow rate as the gas line C. is there.

As shown in FIG. 5, the gas lines A, B and C and the dummy lines A, B and C are connected to both the main line 1 and the vent line 2 via valves 4 to 15, respectively.

The operation of the conventional vapor phase crystal growth apparatus configured as described above will be described. When the gas A is not required for crystal growth, the valve 6 of the gas line A is closed and the valve 7 is open. As a result, the gas A is supplied to the vent line and does not contribute to crystal growth. On the other hand, the valve 4 of the dummy line A whose flow rate is adjusted to be equal to that of the gas line A is open and the valve 5 is closed.
As a result, the hydrogen gas having the same flow rate as the gas A is supplied to the main line. When supplying the gas A to the main line, the gas line A may be connected to the main line and the gas line B may be connected to the vent line. Therefore,
At the same time, the valves 4 and 7 may be closed and the valves 5 and 6 may be opened.

As a result, since there is no change in the flow rate of the gas supplied to the main line and the vent line, the total gas flow rate of the gas supplied to the main line becomes constant, and the pressure of the gas in the main line induced by the fluctuation of the flow rate. Fluctuation is suppressed. The stable gas pressure of the main line is very important when the flow rate of the supplied gas is extremely low.

In a gas supply system without a dummy line,
When a gas line with a large flow rate is connected to the main line The gas flow rate of the main line increases, so that the gas pressure of the main line increases. As a result, in the gas line having a small flow rate, the gas flows backward from the main line to the process gas line. In particular, when trying to fabricate an extremely thin crystal such as a quantum well structure, it is necessary to switch the gas flow every few seconds. In this case, however, if a gas reverse flow occurs, the valve switching timing and the actual supply will be supplied. The timing is different from that of the gas flow, and each crystal composition changes at the crystal interface. (Hereinafter, this state will be referred to as poor interfacial steepness of the crystal due to poor gas outflow.) As described above, in order to obtain a crystalline thin film with excellent interfacial steepness, the process gas line Dummy lines of equal flow of hydrogen have been required.

On the other hand, the above-mentioned reverse flow of gas has a problem that the flow rate of the process gas is small, and in order to keep the flow rate of the gas above a certain level, hydrogen is added to the process gas line having a small flow rate as shown in FIG. The method of connecting the dilution lines has been adopted.

Reference numeral 1 is a main line for supplying a source gas to a crystal growth chamber, 2 is a vent line for discharging a gas not required for crystal growth, and 6, 10 and 14 are for controlling the flow of gas to the main line 1. Air valves 7, 11, 15 are air valves for controlling the flow of gas to the vent line 2, 3
Is a block valve 21, 22, 25, 28 in which 6, 7, 10, 11, 14, 15 air valves are installed close to one block-shaped pedestal, and the flow rate is 200, respectively.
A mass flow controller for controlling 1, 100, 200, 62 is a gas line A for supplying the gas of A, 61 is a dilution line A for supplying hydrogen for diluting the gas line A, and 65 is a gas for supplying the gas of B. Lines B and 68 are C
It is a gas line C for supplying the above gas.

The operation of the conventional vapor phase crystal growth apparatus configured as described above will be described. A for crystal growth
When the above gas is not required, the valve 6 of the gas line A62 is closed and the valve 7 is open. As a result, the gas A is supplied to the vent line and does not contribute to crystal growth. When a large flow rate of, for example, arsine is supplied to the main line 1 as a component gas, the gas line A having a significantly small flow rate of gas is directly affected by the increase in the gas pressure of the main line accompanying the gas switching. The gas flowing in 1 flows backward into the gas line A62. It is necessary to increase the flow rate of the gas line A62 in order to prevent the reverse flow of gas from the main line. Therefore, hydrogen can be supplied to the gas line A to dilute the gas A to increase the gas flow rate and prevent the gas from flowing backward due to the increase in pressure. When the gas A is required for crystal growth, the gas line A may be connected to the main line. Therefore, at the same time, the valve 7 may be closed and the valve 6 may be opened.

Although a slight pressure fluctuation occurs in the main line by switching the valve, the gas in the main line does not flow back to the gas line A. The gas line that requires the dilution gas line does not have a dummy line because the flow rate is low.

By the way, the block valve is a compact integration of a plurality of valves as close as possible to the main line, and the volume of the main line in the block valve is made extremely small, so that a gradual composition change of gas due to gas retention is suppressed. To do. The composition of the gas needs to change abruptly in order to obtain the interface steepness. To this end, it is necessary to make the volume of the main line as small as possible to prevent the gas from staying.

[0012]

However, in the configuration as shown in FIG. 5, since a dummy line is required for each process line, the number of lines to be supplied to the block valve is twice the process gas line. Becomes That is, when switching from the gas line A to the gas line B, it is necessary to switch a total of 8 valves of the valves 4 to 11, and a slight variation in valve controllability causes a pressure fluctuation in the main line.

Further, since the block valve has a high unit price per line, it was necessary to reduce the number of lines of the block valve as much as possible.

On the other hand, in the structure shown in FIG. 6, the number of lines of the block valve is small, but pressure fluctuations occur in the main line, and it is impossible to manufacture an ultrathin film with high accuracy. In order to obtain stable crystal film thickness controllability, a dummy line for stabilizing the main gas pressure is required for each process line in addition to the dilution line for adjusting the flow rate. However, the structure has the problem that the number of lines of the block valve cannot be reduced after all.

In view of the above point, the present invention is composed of a process gas line and a balance line for supplying a gas necessary for keeping the viscosity flow rate product of the supply gas constant to each process gas line as an inert gas such as hydrogen. By using such a gas supply line, the viscosity flow rate products of a plurality of gas supply lines that do not supply gas to the growth chamber at the same time are made constant. Only one dummy line is required for this gas supply group. Therefore, it is not necessary to install dummy lines (the number of gas supply lines in the group-1), and the number of block valves is also reduced (the number of gas supply lines in the group-1). As a result, not only was it possible to form ultra-thin films with extremely stable crystallinity and excellent interface steepness, but it was also cheap because the number of lines required for expensive block valves was reduced to about half. It is an object of the present invention to provide a vapor phase growth apparatus having a simple gas supply line with a valve structure.

[0016]

In order to solve the above problems, the present invention provides a process gas line for supplying a process gas, a balance line for supplying a flow control gas to the process gas line, the process gas line and the process gas line. The gas supply line includes a gas supply line including a balance line and a dummy line for supplying a flow rate adjusting gas, and the gas supply lines in the gas supply group do not simultaneously supply process gas to the main line. Use as a phase growth device.

The steps of adjusting the flow rate of the balance line so that the viscosity flow rate products of the dummy line and the gas supply line are equal, and the step of supplying the process gas of the gas supply line necessary for growth to the main line are all included. And a step of supplying the gas from the dummy line to the main line only when the process gas in the gas supply line is not supplied to the main line.

[0018]

According to the present invention, in order to make the viscosity flow rate product of each gas supply line constant, a balance line is provided for each gas line so that the gas viscosity flow rate product has a constant value. .. The pressure generated in the pipe is ΔP =
It is expressed by 32 · μ · L · u / (g · d · d). Where d is the inner diameter of the tube or needle valve, g is the acceleration of gravity, L is the length, μ is the viscosity of the fluid, and u is the average velocity of the fluid. When the same pressure difference ΔP is generated in fluids having different viscosities, it is necessary to make μ · u equal. However, when the flow rate exceeds the Reynolds number Re = d · u · ρ / μ, the pressure difference ΔP = f · L · ρ · u · u / (2 · g · m), which is the product of the square of the flow rate and the specific gravity. For the sake of convenience, f ・ ρ ・ u
-U is also shown as a viscosity flow rate product. Here, f is a friction coefficient, and m is a hydraulic radius.
n depth), ρ is the density of the fluid. There is no problem if the gas supplied through the balance line is an inert gas, and hydrogen, nitrogen, etc. are suitable. This balance line makes the viscosity flow rate product of each gas supply line flowing into the block valve constant. An example of the gas supply group is a gas line of the same component, which is a gas line that does not flow gas into the main line at the same time. For example, as shown in FIG. 3, InGaAsP (λ _g = 1.3μ
m) and InGaAs quantum well structure and InGaAs
TEG in the case of forming a waveguide layer of P (λ _g = 1.0 μm)
FIG. 2 shows a TEG group 50 which is a group of gas supply lines. The TEG flow rate is 100 ccm for each of the TEG gas supply lines A81, B84, C86.
And 160 ccm and 30 ccm are required, and these two gas flow rates are supplied from different TEG bubblers through individual mass flow controllers set to 100 ccm, 160 ccm and 30 ccm, respectively. When growing while changing the flow rate of each quantum well layer with a mass flow controller of one process gas line, the growth time of each layer is about 10 seconds, whereas the flow rate of the mass flow controller is 1
Better interface steepness cannot be obtained by stabilizing after an adjustment period of about a second. Here, the gas supply amount is 10
When fixed at 0 ccm, 160 ccm, 30 ccm and supplied, 100 ccm, 1 corresponding to each flow rate
Dummy lines of 60 ccm and 30 ccm are required respectively. However, by providing the balance lines A80, B83, and C85 of 100 ccm, 40 ccm, and 170 ccm respectively to the TEG gas line and mixing the hydrogen gas at the respective flow rates into the gas line,
As the flow rate of the gas supply lines A87, B88, C89, which is the sum of the flow rate of the TEG gas line and the flow rate of the balance line, 200 cc of mixed gas is supplied. In this case, since the two concentrations of TEG gas are not supplied at the same time, 200 cc of hydrogen may be supplied from the dummy line 83 only when the TEG gas is not supplied to the growth chamber. When the waveguide layer and the quantum well structure are produced, the TEG gas of each concentration is switched and used, so that it is not necessary to connect the dummy line to the growth chamber. As described above, in the conventional case, three dummy lines are required for three TEG gas lines, so that a valve block with a total of six 12 valves has been required. However, by making the flow rates of the gases that are not used at the same time equal in the balance line, the dummy line may be of one system, and it becomes a block valve of four systems and eight valves, and the number of valves is reduced to 2/3. In particular, since there is only one dummy line, it is not necessary to switch the valves of the dummy lines corresponding to the respective process gas lines when switching the valves between the gas lines. Therefore, when growing different crystals, the number of valves switched at the crystal interface is halved, and pressure fluctuations in the main line are suppressed.

When this apparatus is used, the effect of reducing the number of block valves in the dopant line is great. As shown in FIG. 1, when InP-based crystal growth is performed, DMZn, DEZn, H ₂ Se, H ₂ S, and SiH are used as dopants.
₄ , CpMg, etc. are used. If dummy lines are set for each of these dopants,
6 lines of dummy lines are required, and 12 lines of valve blocks are required. However, if hydrogen gas is supplied by a balance line so that the flow rates of the gas supply lines are equal to each dopant, one dummy line is sufficient, and seven valve blocks can be configured to form five valve blocks. It can be used for supplying other gas. Valve block 1
Since the price per line is about three times the price of one mass flow controller, the price of the valve block system including the additional mass flow controller is about 70% of the conventional price. As described above, the valve block is used as the gas switching valve to the growth chamber, but it is similarly effective when the price of the valve is higher than the price of the mass flow controller.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a vapor phase crystal growth apparatus in an embodiment of the present invention.

In FIG. 1, 1 is a main line for supplying a source gas to a crystal growth chamber, 2 is a vent line for discharging a gas not necessary for crystal growth, and 4 is a flow line for controlling the gas flow to the main line 1. An air valve, 5 is an air valve that controls the flow of gas to the vent line 2, 3 is a block valve in which the air valves of 4 and 5 are installed close to one block-shaped pedestal, and 10 is a mass flow controller that controls the gas flow rate, 50 is TEGa group, 51 is A
sH ₃ group, 52 is TMI group, 53 is PH ₃ group, and 54 is a dopant group.

InGaAs / InGaAs shown in FIG.
In order to grow a crystal of the P MQW laser structure, a crystal growth apparatus in which an AsH ₃ group, a PH ₃ group, a TEGa (trimethylgallium) group, a TMI (trimethylindium) group and a dopant group are connected to a block valve is required. That is, there are AsH ₃ group, PH ₃ group, TEGa group, and TMI group, which have the same concentration but different flow rates, as gases that do not simultaneously supply the same kind of gas to the main line during crystal growth. Various dopant groups and the like can be mentioned because they are not doped with a type dopant together. The process gas such as TEGa is mixed and adjusted in the balance line so that the flow rate becomes the same as that of the other supply gas in the group. As a result, when different crystals are continuously grown, the gas may be supplied by switching the valves between the gas supply lines having the concentrations required for the respective crystals. In this case, it is not necessary to switch the valve of the dummy line for flow rate adjustment because the viscosity flow rate product is the same in any gas supply line, and only when growing a crystal that does not use the gas of that component If the dummy line is connected to the main line, the pressure in the main line will not change.

AsH ₃ which supplies AsH ₃ gas, which causes pressure fluctuations due to high viscosity in the gas supply group, and which is a reason that a good interface cannot be obtained by the conventional method.
The gas supply line group 51 will be described as a representative.

AsH ₃ group 51 is balance line A
61, an AsH ₃ (A) process line 62 (hereinafter a process line is abbreviated as PL), a dummy line 60, a balance line B 64, an AsH ₃ (B) PL 65, a balance line C 67, and an AsH ₃ (C) PL 68. The balanced lines A61 and AsH ₃ (A) PL62 is connected to gas supply lines A70, balance line B6
4 and AsH ₃ (B) PL 65 are connected to each other to connect a gas supply line B 71, a balance line C 67 and AsH ₃ (C) PL.
68 is connected to form a gas supply line C72.

The flow rate of the mass flow controller is 20 to 3
00ccm, 21 is 181ccm, 22 is 77ccm,
24 is 15 ccm, 25 is 200 ccm, 27 is 260
cccm and 28 are 20 ccm.

The operation of the gas flow of the AsH ₃ group 51 will be described below. The AsH ₃ (A) PL62 flowing 20% -AsH3 gas 77Ccm, the balanced line-A61 flow 181ccm hydrogen gas. These gases are mixed in the gas supply line A70. Similarly, AsH
₃ (B) PL65 has 20% -AsH ₃ gas 200 scc
m and a balance line B64 with hydrogen gas of 15 ccm. These gases are mixed in the gas supply line B71. AsH ₃ (C) in the PL68 10% -AsH ₃ Gas 2
0 sccm, 26 hydrogen gas in the balance line C67
Flow 0 ccm. These gases are mixed in the gas supply line C72. The flow rates of the balance lines A61, B64, C67 are set so that the viscosity flow rate products of the gas supply lines A70, B71, C72 and the dummy line 60 are equal.

There are three types of AsH ₃ (A) 62, As.
The reason why the flow rates of H3 (B) 65 and AsH3 (B) 68 are different is shown below. When continuously growing crystals of different compositions, if the flow rate of the mass flow is changed in only one process line according to the composition of the growing crystals,
It takes time for the flow rate of the mass flow controller to stabilize, and good interface steepness cannot be obtained. Therefore, it is necessary to set the flow rate of AsH ₃ required for each crystal in advance as an independent line and switch the line for the crystal of each composition to obtain a crystal having excellent interface steepness.

A valve control method for obtaining the laser structure shown in FIG. 3 will be described with reference to Table 1. To obtain a quantum well structure composed of the well layer 43 and the barrier layer 42, TEGa and AsH are used.
It is necessary to change the flow rate of ₃ corresponding to each crystal, but here, a valve control method of AsH ₃ is particularly shown.

In FIG. 3, n-I is formed on an InP single crystal substrate 40.
nGaAsP (λ = 1.0 μm) waveguide layer 41, InG
InAsG with aAsP (λ = 1.3 μm) as the barrier layer 42
A quantum well structure in which aAs is a well layer 43 and a laser structure including a p-InP clad layer 44 are shown.

A crystal is grown to have this laser structure.
AsH₃Explain gas control in detail
It The AsH3 gas is used for the waveguide layer 41, the barrier layer 42, and the well.
When growing each of the layers 43, a different composition of gas is used.
Space is required. InGaAsP (λ_g= 1.3 μm)
Quantum composed of barrier layer 42 and InGaAs well layer 43
AsH when producing a well structure₃As gas control
Is a process gas when the InGaAsP waveguide layer 41 is grown.
20% of 10% AsH3 as InC, InGaAs
20% of process gas A for growing the P barrier layer 42
AsH₃The gas is 77 ccm and the InGaAs well layer 43 is formed.
20% -AsH as process gas B for long time₃Gas 2
It is necessary to supply 00 ccm. 15 for each film thickness
When setting 0 nm, 10 nm, 6 nm When supplying gas
The intervals are 8 minutes 34 seconds, 20 seconds, and 8 seconds, respectively.
Flow using mass flow controller only in process line
When the amount is changed, it takes about 2 seconds until the flow rate stabilizes.
It takes time. This time is comparable to the deposition time of 5 atomic layers
Therefore, the steepness of the interface deteriorates. Therefore, AsH ₃
Process gas A, B, which has three gas flow rates for
It is necessary to set C. That is, as gas A
20% of 77 ccm-AsH₃, 200cc as gas B
20% of m-AsH₃, 10% of 20ccm as gas C
-AsH₃Correspond to each.

Gas supply lines A70, B71, C72
The flow rate of hydrogen on the balance line to keep the flow rate constant is 181 ccm, 15 ccm, and 260 ccm, respectively.
Is. Total flow rate of mixed gas is 258 cc, 215 cc
m, 280 ccm. The hydrogen gas flow rate of the dummy line at this time is 300 sccm. The flow rate of the mixed gas is different from the flow rate of the gas in the dummy line because the AsH ₃ gas is viscous, and the effect of this gas viscosity is P
This is especially problematic when a flow rate of 100 ccm or more is applied at a high concentration such as H ₃ or AsH ₃ , and for example, the dummy line 3
For 00 ccm, 100% PH ₃ is about 179 ccm.

Table 1 shows opening and closing of the valve. When the substrate temperature rises before the growth of the waveguide layer, only PH ₃ is supplied, and AsH ₃ gas is not necessary, so hydrogen in the dummy line 60 is supplied to the main line in advance.
70, B71, C72 are connected to the vent line.
Valves 4, 7, 11, 15 are open, 5, 6, 10, 14
Is closed. After the temperature is raised, the waveguide layer 41 is grown. In this case, it is necessary to connect the dummy line to the vent line and the line C to the main line at the same time. That is, the valves simultaneously close 4,15 and open 5,14. Next, the barrier layer 42 is grown. Gas supply line C is connected to the vent line and at the same time gas supply line A is connected.
Need to be connected to the main line. That is, the valves simultaneously close 7,14 and open 6,15. Next, the well layer 43 is grown. The gas supply line A70 is connected to the vent line, and the gas supply line B71 is connected to the main line. The valves close 6, 11 at the same time, 7,
Open 10. After that, switching between the line A and the line B is repeated ten or more times until the growth of the quantum well structure is completed. In the above operation, since there is no change in the viscosity flow rate product of the gas supplied to the main line and the vent line, the gas pressure in the main line hardly changes due to valve switching.

In the dopant group 54 of FIG. 1,
The supply of hydrogen through the balance line 93 exhibits the same effect as that of the dilution line when the flow rate of the supplied gas such as H ₂ Se 94 which is a doping gas is as small as 15 sccm. In the case of a doping gas, 200 ppm of DMZn is 134 scc for the gas supply line A91.
The balance line 90 is supplied with hydrogen at a flow rate of 64 sccm. The dummy line 92 supplies 100% hydrogen at 200 sccm. The total flow rate of DMZn and hydrogen for balance is 198c.
However, since the DMZn gas is viscous, this causes resistance to the flow when flowing through the main line and causes pressure, so the flow rate is reduced in advance. 100 ppm of H ₂ Se is used for the gas supply line B94.
It is supplied at a flow rate of 5 sccm, and the balance line 9
3 supplies hydrogen at a flow rate of 185 sccm. H ₂
After growing the n-InP crystal to which Se is added, H _{2 is} further added.
When n-InGaAsP doped with Se is grown, P
The gas flow rate of H ₃ largely changes from 300 sccm to 100 sccm. In that case, the gas flow rate of the main line slightly changes during the gas switching time of 0.05 to 0.07 seconds. As a result, in the case of only the H ₂ Se line having a small flow rate, the gas may flow backward from the main line. As with other doping gases, set the balance line to 18
By setting the flow rate to 5 sccm, the flow rate of the gas supplied to the main line is 200 sccm and no backflow occurs.

Table 2 shows the valve opening / closing sequence of the conventional example shown in FIG. Barrier layer 42 where steepness is particularly important
According to the present invention, it is understood that the valve operation was halved during repeated growth of the well layer 43 about 10 times.

In the above description, it is assumed that the main line 1 and the vent line 2 are in a reduced pressure state of 200 Torr, and the growth chamber is in a reduced pressure state of 70 Torr. As a result, the pressure fluctuations in the main line and the vent line were reduced from 10 torr to 2 torr or less, and the interface steepness of the crystal was reduced from 1.5 nm to 0.5 nm or less.

As described above, according to this embodiment, each process gas line that is not used at the same time is provided with a balance line for equalizing the viscosity flow rate products of the respective supply gas lines. The number of existing dummy lines can be reduced to one, and the number of valves simultaneously switched can be reduced by half to improve crystallinity and interface steepness.

Although the AsH ₃ gas line is used in this embodiment, any gas may be used as long as it does not flow simultaneously. Further, the growing crystal is InP-based, but may be other vapor-phase growth such as GaAs-based, other compound semiconductor, oxide-based, or insulating film-based. Although hydrogen is supplied as the balance line and the dummy line, other inert gas may be used. Although a block valve is used as a gas switching valve for the growth chamber, it may be a normal valve or a valve having another structure. Although the organic metal gas is used as the process gas, it may be a process gas for semiconductors and superconducting materials such as hydride and silane.

[0038]

As described above, according to the present invention,
Not only is it possible to form an ultra-thin film with excellent interface steepness by halving the number of valve changes during thin film formation, but it is also inexpensive because the number of lines required for an expensive block valve is significantly reduced It is possible to provide a vapor phase growth apparatus capable of producing a crystal that is simple but extremely stable, and its practical effect is extremely large.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vapor phase crystal growth apparatus according to an embodiment of the present invention.

FIG. 2 shows T of the vapor phase crystal growth apparatus in the embodiment of the present invention.
Structure of EGa Group

FIG. 3 is a laser structure diagram in an embodiment of the present invention.

FIG. 4A of the vapor phase crystal growth apparatus in the embodiment of the present invention
Block diagram of sH ₃ group

FIG. 5 is a block diagram of a conventional vapor phase crystal growth apparatus.

FIG. 6 is a block diagram of a conventional vapor phase crystal growth apparatus.

FIG. 7 is a diagram showing a valve control method using the vapor phase growth apparatus of the present invention.

FIG. 8 is a diagram showing a conventional valve control method.

[Explanation of symbols]

 1 Main line 2 Vent line 3 Block valve 60 Dummy line 61 Balance line A 62 Gas line A 64 Balance line B 65 Gas line B 67 Balance line C 68 Gas line C 51 AsH3 group

Claims (3)

[Claims] 1. A process gas line for supplying a process gas, a balance line for supplying a flow rate adjusting gas to the process gas line, a gas supply line composed of the process gas line and the balance line, and a flow rate adjusting gas. A vapor phase growth apparatus comprising a gas supply group including a supply dummy line, wherein the gas supply lines in the gas supply group do not simultaneously supply process gas to the main line. 2. The vapor phase growth apparatus according to claim 1, wherein the balance line comprises a gas supply line adjusted to have a viscosity flow rate product equal to that of the dummy line. 3. A step of adjusting the flow rate of a balance line so that the viscosity flow rate products of the dummy line and the gas supply line are equal, and a step of supplying the process gas of the gas supply line necessary for growth to the main line. And a step of supplying gas from the dummy line to the main line only when the process gas of all the gas supply lines is not supplied to the main line.