JP2001335399A - Vapor growth method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor growth method by which a gas stream in a reaction tube is made to be a complete laminar flow, a thin film is efficiently grown with a uniform composition and thickness and the yield from a raw material gas can be improved. SOLUTION: In the vapor growth method for forming a compound semiconductor thin film comprising at least two-component elements on a substrate by introducing a raw material gas comprising at least two kinds of gases and a purge gas into a reaction furnace in which the substrate is set, flow velocities of the raw material gas and the purge gas are controlled so as to satisfy the expression, 8.0>=vP/vG∞0.8 (wherein vG, is the velocity of the raw material gas and vp is the velocity of the purge gas) to make the raw material gas and the purge gas in the reaction furnace a two-layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a compound semiconductor thin film comprising at least two types of elements on a surface of a substrate by introducing at least two kinds of source gases and a purge gas into a reactor in which a substrate is installed. The present invention relates to a technique suitable for being applied to a vapor phase growth method.

[0002]

2. Description of the Related Art In recent years, a technique of growing an epitaxial film on a compound semiconductor substrate such as gallium arsenide (GaAs) or indium phosphide (InP) has attracted much attention. According to recent technologies, indium gallium arsenide (InGaAs), indium gallium phosphide (InGaP), aluminum gallium arsenide (AlGaAs), indium aluminum arsenide (In) are used as epitaxial films.
AlAs), indium gallium arsenide phosphorus (InGaAs)
A so-called mixed crystal layer such as sP) can also be grown.

One of the effective methods for growing these epitaxial films is metal organic chemical vapor deposition (MOCVD).
There is. The MOCVD method includes trimethylindium (TMI), trimethylgallium (TMG), triethylgallium (TEG), and trimethylaluminum (TMG).
A) and so-called organometallic gas and arsine (As)
A volatile gas such as H ₃ ) or phosphine (PH ₃ ) is introduced into the reaction furnace together with hydrogen (H ₂ ) as a carrier gas, and the raw material is thermally decomposed near the substrate. This is a method of growing a thin film on a substrate by heating to a growth temperature of a compound semiconductor. In addition, as a raw material gas, an organic metal such as trimethyl arsenic or tert-butyl phosphine can be used instead of a gas such as arsine or phosphine.

A compound semiconductor thin film grown on a substrate by the MOCVD method is required to have a uniform mixed crystal composition and a uniform film thickness without surface defects such as particles from the application. As an apparatus for growing such a thin film,
For example, a horizontal vapor phase growth apparatus as described in Japanese Patent Application Laid-Open No. 9-260291 (vapor phase growth apparatus and method) is known.

FIG. 4 is a schematic sectional view of a conventional horizontal vapor phase growth apparatus. Reference numeral 13 denotes a reaction tube of a vapor phase growth apparatus provided with a gas introduction unit 11 at one end and a gas exhaust tube 12 at the other end, and is installed with its axis being horizontal. A susceptor 15 for holding a substrate 14 is provided inside the reaction tube 13.
And a flow channel 16 on the upstream side of the susceptor 15.
And two partition plates 17 and 18 on the gas introduction unit 11 side and an RF (high frequency) coil 20 for heating the substrate 14.

In this vapor phase growth apparatus, the partition plates 17,
18, the gas flow path is changed to the first flow path 21, the second flow path 22,
It is divided into three of the third flow path, and predetermined gases (first raw material gas G1, second raw material gas G2, growth promoting gas G3) are introduced from each flow path, and the group III-V or group II-VI is introduced. A thin film of a compound semiconductor is grown. Specifically, the first raw material gas G1 is introduced from the first flow path 21 close to the substrate surface, and the second flow path 2
By introducing the second source gas G2 from Step 2, the source gas concentration in the vicinity of the substrate can be increased, the usage efficiency of the source gas can be greatly increased, and the volatile element can be prevented from volatilizing from the grown thin film. I have to.

Further, by providing a growth promoting table 19 in the reaction tube 13 to reduce the gas flow path cross-sectional area near the substrate surface, the gas flowing in the reaction tube 13 is pressed against the substrate surface, Since the gas flow rate can be increased, by appropriately setting the shape of the growth promotion table 19, the effective material concentration near the substrate is increased, and the thin film is efficiently grown in a better state. I have.

[0008]

However, in the above-described vapor phase growth apparatus, the effective source concentration in the vicinity of the substrate can be increased by the growth promotion table 19 to efficiently consume the source gas. There is a problem that the flow of gas inside is disturbed. That is, at least the growth promoting gas G3 flows along the inclined surface of the growth promoting table 19, so that the laminar flow of the source gases G1 and G2 is disturbed, and as a result, the concentration of the source gas near the substrate varies. It was found that it was difficult to grow a thin film with a uniform composition and thickness on a substrate.

If the gas flow is disturbed in the reaction tube 13, the reaction products of the raw material gas are likely to precipitate not only on the substrate surface but also on the wall surface of the reaction tube 13, and the reaction separated from the wall surface. The product may be carried by the gas flow and adhere to the surface of the grown thin film to cause surface defects such as particles.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and makes a gas flow in a reaction tube a perfect laminar flow, grows a thin film with a uniform composition and film thickness, and improves the utilization efficiency of a raw material gas. It is an object of the present invention to provide a vapor phase growth method which can be performed.

[0011]

According to the present invention, at least two kinds of source gases and a purge gas are introduced into a reactor provided with a substrate to form a compound semiconductor thin film on the surface of the substrate. In the vapor phase growth method, when the flow rate of the source gas at the inlet for introducing the source gas and the purge gas into the reactor is v _G , and the flow rate of the purge gas is v _P , the flow rate ratio v _P / v _G is controlled. As a result, the raw material gas and the purge gas flowed in the reaction furnace in a laminar flow state. Desirably, the flow rate ratio v _P / v _G is set to be 0.8 or more and 8.0 or less.

Thus, the source gas can be supplied at a uniform concentration to the surface of the substrate installed in the reaction furnace, so that a thin film having a composition and a film thickness can be grown, and the utilization efficiency of the source gas can be improved. Can be improved.

More preferably, the ratio of the flow rates v _P / v _G
Should preferably be 1.3 or more and 4.0 or less. Further, when the ratio v _P / v _{G of the} flow velocity is set to be 2.0 or more and 3.0 or less, the effect is more remarkably exhibited.

The flow rate v _G of the source gas at the inlet is
And the flow rate v _P of the purge gas is 30 at 50 torr.
When the flow rate is set to not less than cm / sec and not more than 1000 cm / sec, the flow of the gas introduced into the reaction tube can be reliably made to be a laminar flow. As described above, the ratio v _P / of the flow rate v _G of the source gas at the inlet and the flow rate v _{P of the} purge gas is obtained.
Even if the range of v _G is determined, if the absolute value of the flow velocity is extremely large or small, the gas flow generated in the reaction tube does not become laminar, so in order to surely generate laminar flow in the reaction tube, It is important to determine the range of flow rates.

Desirably, the flow rate v _G of the source gas and the flow rate v _P of the purge gas at the inlet are 5 to 50 torr.
When it is set to 0 cm / sec or more and 500 cm / sec or less, laminar flow can be more easily generated.

A gas obtained by diluting a source material of a Group 3B element and a source material of a Group 5B element with a gas such as hydrogen as the source gas is used as a purge gas for a gas phase growth reaction of hydrogen, helium, argon, nitrogen, or the like. Gases that do not contribute can be used.

For example, as a source gas containing a Group 3B element, trimethylindium, trimethylindium,
There are triethylgallium, trimethylaluminum and the like, and the source gas containing a Group 5B element includes arsine and phosphine.

Particularly remarkable effects can be obtained by using a group III-V compound semiconductor substrate and applying it to a vapor phase growth method for growing a group III-V compound semiconductor on the substrate.

Hereinafter, the contents of the study and the results of the research leading up to the present invention will be outlined.

First, in order to grow a thin film with a uniform composition and thickness in the organic metal growth method, it is important to introduce a raw material gas at a uniform concentration near the substrate surface. It is considered desirable that the gas flow be laminar.

In addition, if the gas flow in the reaction furnace can be made laminar, the raw material gas does not come into contact with the wall surface or the like facing the substrate in the reaction furnace, so that the reaction product does not precipitate on the wall surface. It is considered that the utilization efficiency of the reaction product can be remarkably improved and the reaction product can be prevented from peeling off from the wall surface and adhering to the surface of the thin film grown on the substrate to cause surface defects.

The inventors of the present invention have repeatedly studied to make the gas flow in the reaction furnace laminar, and as a result, if the flow rate of the gas introduced into the reaction furnace is appropriately adjusted, the gas flow in the reaction furnace will be reduced. It was speculated that the gas flow could be effectively made laminar. Based on this inference, the gas flow in the reactor when the flow rates of the source gas and the purge gas were changed and introduced into the reactor in the vapor phase growth apparatus as shown in FIG. 1 was simulated by a computer.

Here, the reactor of the metal organic chemical vapor deposition apparatus shown in FIG. 1 has a cylindrical shape having a low height as a whole, and gas introduction pipes 5 and 6 are provided at the center of the lower wall. Device. A source gas is introduced through a source gas introduction pipe 5, and a purge gas is introduced through a purge gas introduction pipe 6. The detailed configuration of the vapor phase growth apparatus of FIG. 1 will be described in the section of the embodiment.

As a result of the simulation, it was found that when the flow rate of the purge gas with respect to the flow rate of the raw material gas was increased to some extent, almost no turbulence occurred in the reactor. For example, FIG. 3 shows a simulation result of a gas flow in the reactor when the total flow rate of the introduced gas is set to 60 l / min. FIG. 3 (a) shows that the source gas (total flow rate including hydrogen) is 50%.
1 is a simulation result when a purge gas is introduced into a reaction furnace at a rate of 10 l / min. Since turbulence occurs near the gas inlet (corresponding to 5a and 6a in FIG. 1), it is considered that the raw material gas easily comes into contact with the lower wall surface of the reactor near the gas inlet and a reaction product is deposited. .

On the other hand, FIG. 3B shows that the source gas (total flow rate including hydrogen) is 30 l / min and the purge gas is 30 l / mi.
3 is a simulation result when n was introduced into the reaction furnace. Since the gas flows uniformly from the gas inlet to the gas outlet, it is considered that the source gas can efficiently grow a thin film by contacting the substrate surface.

An experiment was carried out based on the simulation results. As a result, when the thin film was grown under the conditions of a source gas of 30 l / min and a purge gas of 30 l / min (FIG. 3B), the source gas was reduced to 50 l / min. The utilization efficiency of the raw material gas was improved by 15% as compared with the case where the thin film was grown under the conditions of 10 min / min and a purge gas of 10 l / min (FIG. 3A).
When the surface of the thin film grown under the conditions of FIG. 3B was observed with an optical microscope, the grown thin film was good without any surface defects such as particles.

Thus, the flow rate of the introduced gas can be adjusted to make the gas flow in the reactor a laminar flow, and if the gas flow in the reactor is made a laminar flow, the utilization efficiency of the raw material gas can be greatly improved. It was confirmed that a thin film free from surface defects could be obtained while improving.

Therefore, in order to determine the optimum conditions for the flow ratio between the source gas and the purge gas, the above experiment was repeated while changing the flow ratio according to the combination shown in Table 1. The dimensions of the source gas inlet and the purge gas inlet shown in Table 1 are examples of the dimensions of the inlet in the vapor phase growth apparatus as shown in FIG.

[0029]

[Table 1]

As a result, the flow ratio (= purge gas flow rate / source gas flow rate) was changed from 0.2 (10/50) to 2 (40/2).
In the case of (0), no surface defects such as particles were observed on the surface of the grown thin film, and it was found that the film could be used practically. Furthermore, when the flow ratio is 0.33 (15 /
The utilization efficiency of the raw material gas in the range from 45) to 1 (30/30) was improved by 12% as compared with the case where no purge gas was supplied. In addition, the flow ratio is 0.5 (20/40) to 0.71.
Source gas utilization efficiency in the range of (25/35) is 18%
Improved and found to be more desirable.

From this experiment, in the vapor phase growth apparatus shown in FIG. 1, it is possible to determine the range of the flow rate ratio between the source gas and the purge gas for obtaining a good thin film by generating a laminar flow in the reaction furnace. Was.

The present inventors have also noticed that laminar flow does not occur if the gas flow rate in the reactor is too slow or too fast. Therefore, in the vapor phase growth apparatus shown in FIG. 1, the distance (radius) from the central axis to the end point of the partition plate 8 is 3
cm, the height from the partition plate 8 to the upper wall surface of the reactor is 4.
A computer was used to simulate a gas flow in the reaction furnace when a source gas was introduced from the source gas inlet 5a of 02 cm. Table 2 shows the conditions under which the above-mentioned simulation was performed, and in particular, the conditions under which the gas flow in the reaction furnace was in a laminar flow state by the simulation is shown by a mesh portion. According to the simulation results, the gas flow rate in the standard state is 10 to 300 l / min, that is, the flow rate is 2.20 to 300 l / min.
At 65.98 cm / sec, the gas flow was found to be laminar. In order to make the gas flow laminar, the gas flow rate is 15 to 150 l / min, that is, the flow rate is 3.3.
It turned out that it is desirable to set it to 0 to 32.99 cm / sec.

[0033]

[Table 2]

The flow rate conditions described above are for the case where the gas is in a standard state. However, when the gas is actually grown in a vapor phase, the flow rate may be converted into the flow rate under the growth conditions (temperature and pressure). That is, as shown in Table 2, the pressure was set to 50 torr.
r, the flow rate is 30 to 1000 cm / sec.
c, preferably 50 to 500 cm / sec.

By controlling the flow rate ratio and the absolute value of the flow rate of the introduced gas as described above, the gas flow in the reaction furnace can be efficiently made laminar, and the utilization efficiency of the raw material gas is significantly improved. You can now let.

The above-described flow rate ratio condition is effective in the vapor phase growth apparatus used in the present simulation and the present experiment, and the flow rate ratio at the gas inlet (=
The present invention has been found to be applicable to the case where the shape and size of the inlet are different or the total flow rate of the gas is different from the expression (purge gas flow rate / source gas flow rate).

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a vapor phase growth method according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing a configuration example of a metal organic chemical vapor deposition apparatus used in this embodiment. In the figure, reference numeral 1 denotes a reaction furnace of the metal organic chemical vapor deposition apparatus, which has a low cylindrical shape as a whole, and each wall of the reaction furnace 1 is made of, for example, stainless steel, and a lower wall 10 Is covered with an inner wall member 10a made of stainless steel or quartz having a thickness of about 3 mm so that reaction products are not easily precipitated. Further, gas introduction pipes 5 and 6 are provided at the center of the lower wall body.

Reference numeral 2 denotes a substrate holding table which is rotatably suspended in the reaction furnace 1 by a rotary shaft 3, and is provided on a carbon disk 2b formed in a disk shape and on the same circumference inside the carbon disk. And a plurality of susceptors 4a. The substrate 4 is attached to each susceptor 2a of the substrate holder.
Is installed face down. A multi-stage heater 7 for heating the substrate 4 via the susceptor 2a is provided concentrically outside the reaction furnace.

Reference numeral 5 denotes a source gas introduction pipe having a flange disposed at the center of the lower wall of the reaction tube 1, and reference numeral 6 denotes a purge gas introduction pipe disposed along the outer periphery of the source introduction pipe 5. . In order to make the flow of the raw material gas and the purge gas easily laminar, a partition plate 8 is provided at the end of the flange.
Is provided. The source gas is introduced into the region sandwiched between the substrate holding table 2 and the partition plate 8 as an inlet 5a, and the purge gas flows horizontally in the region sandwiched between the lower wall of the reaction tube 1 and the partition plate 8 as an inlet 6a. be introduced.

Through this raw material gas introduction pipe 5, trimethyl indium (TMI), trimethyl gallium (TM)
Group B source gas such as G), arsine (AsH ₃ ),
A mixed gas of a Group 5B source gas such as phosphine (PH ₃ ) is introduced, and hydrogen (H ₂ ) is supplied through a purge gas introduction pipe 6.
Is introduced into the reaction furnace 1.

An exhaust port 9 is formed on the side of the reaction furnace 1. The raw material gas introduced into the reactor 1 through the inlet 6a via the raw gas introduction pipe 5
Is decomposed on the upstream side of the substrate, flows to the peripheral portion of the substrate holder 2 on the downstream side, and forms an epitaxial film on the substrate 4.
The remaining source gas is discharged to the outside through the exhaust port 9 together with the carrier gas.

Although not shown in the figure, a water cooling jacket is provided on the outer periphery of the rotating shaft 3 and on the outer wall of the lower side wall of the reaction furnace 1, and the temperature inside the reaction furnace 1 is increased by the multi-stage heater and these water cooling jackets. Is controlled.

The above is the schematic configuration of the metal organic chemical vapor deposition apparatus used in this embodiment.

Next, the organometallic vapor phase epitaxy apparatus
For example, as shown in FIG.
On top, a 0.1 μm thick InP film and 0.5 μm thick G
A procedure for sequentially epitaxially growing an aInAs film and a 0.5 μm-thick InP film will be described.

First, power supply to the multi-stage heater 7 of the reaction furnace 1 is started, and circulation of cooling water in each water cooling jacket is started. Then, while the inside of the reaction furnace 1 is sufficiently heated, a raw material gas and a purge gas are introduced, and the growth temperature 6
Control is performed so that the condition is 50 ° C. and the growth pressure is 50 torr.

In the present embodiment, the flow rate is adjusted so that the flow rate ratio (v _P / v _G ) between the source gas and the purge gas becomes 2 in order to grow a good thin film with the gas in the reaction furnace in a laminar flow state. did. It is known from the above simulation and experiment that the gas flow in the reactor becomes laminar if the flow velocity ratio is 2. Therefore, in the present embodiment, the flow velocity ratio is adjusted by adjusting the flow rates of the source gases and the purge gas. In addition, the flow rate described below is a standard state (25 degreeC, 1 atm).

First, as a raw material gas, 0.01 l / min
Of trimethylindium, 0.5 l / min of phosphine, and 39.49 l / min of hydrogen were introduced through the raw material gas introduction pipe 5, and 20 l / min of hydrogen as a purge gas were introduced through the purge gas introduction pipe 6. By supplying these gases for 5 minutes, 0.1 μm of InP is deposited on the InP substrate 4.
m.

Next, 0.002 l / mi was used as the raw material gas.
n trimethylgallium, 0.002 l / min trimethylindium, 0.5 l / min arsine, and 39.496 l / min hydrogen
, And 20 l / min of hydrogen as a purge gas was introduced through a purge gas introduction pipe 6. By supplying these gases for 30 minutes, GaInAs was added to InP on InP.
The growth was 5 μm.

Finally, 0.01 l / mi is used as the raw material gas.
n trimethylindium, 0.5 l / min phosphine, and 39.49 l / min hydrogen were introduced through the raw material gas introduction pipe 5, and 20 l / min hydrogen was introduced as a purge gas through the purge gas introduction pipe 6. . By supplying these gases for 25 min, InP was grown to 0.5 μm on GaInAs.

By controlling the flow rate of the introduced gas in this way, the flow rate ratio between the source gas and the purge gas can be controlled to 2, and the gas flow in the reactor can be made laminar. Of course, the respective flow rates of the source gas and the purge gas also satisfy the range of the flow rates for setting the gas flow in Table 2 to a laminar flow state.

At this time, the temperature condition at the time of growing each thin film is controlled by controlling the flow rate of the water cooling jacket provided on the outer wall of the lower wall body and controlling the temperature of the inner wall member 10 provided on the lower wall body of the reactor 1. Is less than or equal to the decomposition temperature of the raw material gas.
The temperature was adjusted to 50 ° C. Further, the flow rate of the water-cooled jacket provided on the outer periphery of the rotating shaft 5 and the amount of electricity supplied to the multi-stage heater 10 are controlled so that the temperature of the upstream portion of the reaction furnace 1 is 250 ° C. or more, which is higher than the decomposition temperature of the raw material gas, 400 to 6
The temperature was adjusted to 00 ° C.

The thus grown thin film was taken out of the reaction furnace 1 and the surface was observed with an optical microscope. As a result, no surface defects such as particles were observed.

According to this embodiment, the gas flow in the reaction furnace is in a laminar flow state, and the source gas can be supplied at a uniform concentration on the substrate, so that a thin film having a uniform mixed crystal composition and a uniform film thickness can be formed. In addition to the growth, the raw material gas was prevented from coming into contact with the wall surface in the reactor and being deposited on the wall surface as a reaction product. The utilization efficiency of the source gas in the InP growth in the present embodiment was 7.04%, which could be improved as compared with the utilization efficiency of the conventional method of 6.6%. Further, the present invention can be applied to InGaAs growth. In this case, the utilization efficiency of the source gas, which was 6.2% by the conventional method, could be improved to 7.0%.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments. For example, in the present embodiment, the so-called face-down type in which the substrate holder 2 is hung on the rotating shaft 3 and the growth surface of the substrate 4 is directed downward, the substrate holder is provided below the reaction furnace. Needless to say, the present invention can also be applied to a face-up type in which a substrate is placed thereon and the thin film growth surface faces upward.

In this embodiment, a cylindrical reactor having a rotary susceptor is used. However, when a horizontal reaction tube as shown in FIG. 4 is used as the reactor, the flow rate at the inlet is similarly controlled. By doing so, the same effect as in the present embodiment can be obtained.

In this embodiment, two or three types of source gases are mixed and introduced from the source gas introduction pipe 5, but the source gases may be introduced for each type. For example, an introduction pipe may be extended to the reaction furnace introduction port for each type of raw material gas, and a partition plate may be provided in the reaction furnace to control the introduction port flow rate.

[0058]

According to the invention disclosed in the present application,
In a vapor phase growth method for forming a compound semiconductor thin film comprising a binary or more element on the substrate surface by introducing at least two kinds of source gases and a purge gas into a reaction tube in which a substrate is installed, Since the laminar flow is generated in the reaction tube by controlling the flow rate ratio of the purge gas, it is possible to grow a thin film having a uniform composition and thickness, and to significantly improve the utilization efficiency of the source gas. There is.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration example of a metal organic chemical vapor deposition apparatus of the present embodiment.

FIG. 2 is an explanatory diagram showing an example of an epitaxial film grown on an InP substrate in the present embodiment.

FIG. 3 is a simulation result of a gas flow in a reactor.

FIG. 4 is a schematic sectional view of a conventional horizontal vapor phase epitaxy apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal organic chemical vapor deposition apparatus 2a Susceptor 2b Carbon disk 3 Rotating shaft 4 Substrate 5 Source gas introduction pipe 5a Source gas introduction port 6 Purge gas introduction pipe 6a Purge gas introduction port 7 Heater 8 Partition plate 9 Discharge port 10 Lower wall surface 10a Internal member

Continued on the front page (72) Inventor Mitsuhiro Kamoto 3-17-35 Niisominami, Toda-shi, Saitama F-term (reference) 4G077 AA03 BE42 BE45 DB08 DB12 EC09

Claims (7)

[Claims] At least two substrates are placed in a reactor in which a substrate is placed.
In the vapor phase growth method of forming a compound semiconductor thin film on the substrate surface by introducing a kind of source gas and a purge gas, the flow rate of the source gas at an inlet for introducing the source gas and the purge gas into the reactor is set to v _G Wherein, when the flow rate of the purge gas is v _P , the source gas and the purge gas flow in a laminar state in the reaction furnace by controlling the flow rate ratio v _P / v _G. Method. 2. The flow rate ratio v _P / v _G is 0.8 or more.
2. The vapor phase growth method according to claim 1, wherein the value is set to 0 or less. 3. More preferably, the ratio of the flow rates v _P / v _G
The vapor phase growth method according to claim 1, wherein is set to be 1.3 or more and 4.0 or less. 4. A flow rate v _G of a source gas at the inlet.
And the flow rate v _P of the purge gas is 30 at 50 torr.
The vapor phase growth method according to any one of claims 1 to 3, wherein the temperature is not less than cm / sec and not more than 1000 cm / sec. 5. More preferably, the flow rate v _G of the raw material gas and the flow rate v _P of the purge gas at the inlet are 50 torr.
The vapor phase growth method according to any one of claims 1 to 3, wherein the temperature is 50 cm / sec or more and 500 cm / sec or less in a state of r. 6. The method according to claim 1, wherein the source gas is obtained by diluting a source material of a Group 3B element and a source material of a Group 5B element with hydrogen gas, and the purge gas is a hydrogen gas. 5. The vapor phase growth method according to any one of 5. 7. The vapor phase growth method according to claim 1, wherein the substrate and the compound semiconductor thin film formed on the substrate surface are III-V compound semiconductors. .