JPH03211723A - Forming thin film by vapor phase epitaxy, manufacture of transistor, and apparatus for vapor phase epitaxy - Google Patents

Abstract

PURPOSE:To easily form a thin film having an inclined composition in the direction of the thickness by making the reaching quantity per unit time of at least one of a plurality of sorts of raw material gases, which are sprayed to the surface of a substrate, to the surface gradually differ from that of the other raw material gases. CONSTITUTION:The degree of vacuum in a thin film growth chamber 30 is as low as or lower than 1X10<-2>Torr and raw material gas introduction ports 40a-40d are made toward the center of the surface of a substrate 36, therefore, raw material gases sprayed through the raw material gas introduction ports 40a-40d travel straight toward the center of the surface of the substrate 36 and are free from convection and turbulence in the thin film growth chamber 30. Hence the reaching quantity of one or some of the raw material gases can be made differ from that of the other raw material gases by making the interval between opening and closing of one or some of gas passage changing valves and one or some of shutters differ from that of the others. Thereby the growing speed of a thin film with the raw material gases can be changed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for forming a thin film by vapor phase growth represented by MOCVD, a method for manufacturing a transistor, and a vapor phase growth apparatus, and particularly relates to a method for forming a thin film by vapor phase growth represented by MOCVD, and a method for manufacturing a transistor, and a vapor phase growth apparatus. The present invention relates to a method for forming a thin film by vapor phase growth suitable for forming a thin film, a method for manufacturing a transistor, and a vapor phase growth apparatus.

[Conventional technology]

The MOCVD vapor phase growth method of compounds or mixed crystal semiconductors such as ■-■ group and n-■ group using organometallic raw material gas is as follows:
Research and development is being actively conducted in various places as a material that can form high-quality thin films.

FIG. 10 shows the configuration of a typical conventional vapor phase growth apparatus.

The vapor phase growth apparatus shown in FIG. 10 includes a thin film growth chamber 1,
a foreline trap 2, a rotary pump 3 as an exhaust pump, a susceptor 4 for substrate installation, a high frequency coil 6 for heating the substrate, a source gas introduction line 7 whose one end is connected to the thin film growth chamber 1, a vent line 8 whose one end is connected to the upstream side of the foreline trap 2 of the exhaust system;
Raw material gas sources 9a, 9b and mass flow controller 10
a.

10b, and gas flow path switching valves 11a and llb.

Phosphine (PH3) is supplied from the raw material gas source 9a, and trimethylindium C is supplied from the raw material gas source 9b.
(CH3) -I n) (hereinafter referred to as rTM).

Next, using the vapor phase growth apparatus shown in FIG.
A conventional method for growing an In,P thin film on an nP substrate will be described.

Hydrogen gas (H2) highly purified by a palladium purifier (not shown) is passed through a raw material gas introduction line 7, one end of which is connected to the thin film growth chamber 1, and a vent line, one end of which is connected to the exhaust system. 8 and 6Q per minute each.

The inside of the thin film growth chamber 1 is evacuated to about 150 Torr by a rotary pump 3 having a foreline trap 2.

Before the growth of InP, the gas flow path switching valve 11a is
, llb, and the source gas [9a to phosphine (
PH3) whose flow rate was adjusted by the mass flow controller 10a, and hydrogen gas (H2) whose flow rate was adjusted by the mass flow controller 10b for TMI from the source gas source 9b.
) and bubbling at 200cc and 400cc per minute, respectively.
Flow into vent line 8 at a flow rate of cc. Note that the vent line 8 is one of the waste gas lines, and is constantly kept under reduced pressure by the rotary pump 3 that constitutes the exhaust system.

Next, the InP substrate 5 is attached to a load lock mechanism (not shown).
is introduced into the thin film growth chamber 1 using a susceptor 4 and placed in the susceptor 4.

When growing InP, InP installed in susceptor 4
The substrate 5 is heated to 670° C. by the high frequency coil 6. At this time, in order to prevent thermal damage to the surface of the InP substrate 5, the gas flow switching valve 11a is switched to open on the source gas introduction line 7 side, and phosphine is flowed into the source gas introduction line 7 and introduced into the thin film growth chamber 1. .

Then, after about 20 minutes, the gas flow switching valve 11b is switched to open the raw material gas introduction line 7 side, and TMI is introduced into the thin film growth chamber 1 through the raw material gas introduction line 7 to grow InP. In other words, when growing an InP thin film, each source gas is
The gas flow path is switched from the vent line 8 to the source gas introduction line 7 by the gas flow path switching valves 11a and 11b, and the gas is introduced into the thin film growth chamber 1 through this source gas introduction line 7.

In addition, addition of dopants to the grown film, and even InP
When growing a laminated multilayer film of PG and A, these raw material gases are introduced into the thin film growth chamber 1, so dopants such as hydrogen sulfide (H, S) are used as n-type dopants. , Ga and AsyK materials include trimethylgallium ((CH,)3Ga) (hereinafter rTM
GJ) and arsine (AsH,) to the raw material gas introduction line 7 and vent line 8, respectively, are connected to the two raw material gases, phosphine and TMI.
In addition to the piping that guides the A multilayer film of InP/InGaAs is formed.

Next, InP/GaInAs was grown using conventional vapor phase growth technology.
A process for manufacturing a /InP double heterostructure bipolar transistor will be described.

Hydrogen gas highly purified by a palladium purifier (
H2) is flowed into the thin film growth chamber and into the vent line, one end of which is connected to the exhaust system, at a rate of 6Q per minute.

Then, the inside of the thin film growth chamber is evacuated to about 100 Torr using a rotary pump having a foreline trap.

When growing a thin film, phosphine (PH,,)t
Arsine (A s H,), TMI, and triethyl gallium (hereinafter referred to as rTEGJ) are used as source gases. Furthermore, diethylzinc (DEZn) and disilane (Si, H, ) are used as P-type and n-type impurities, respectively.

Before growing the thin film, the flow rates of phosphine, arsine, diethylzinc, and disilane were adjusted using mass flow controllers at 100 cc/min.

Flow into the vent line at flow rates of 90cc, 10cc, and 5cc.

On the other hand, TMI and TEG are bubbled with hydrogen gas, the flow rates of which are adjusted using mass flow controllers, respectively, to flow at flow rates of 400 cc and 300 cc per minute.

Next, the semi-insulating InP substrate is introduced into the thin film growth chamber using a load-lock mechanism, placed on a susceptor, and heated to a film growth temperature of 650° C. using a high-frequency coil. At this time, in order to prevent thermal damage to the surface of the semi-insulating InP substrate, phosphine is introduced into the thin film growth chamber through a source gas introduction line that is switched from the vent line.

After holding the semi-insulating InP substrate at 650°C for 20 minutes, T
MI and disilane are introduced into the thin film growth chamber through a source gas introduction line switched from the vent line, and a silicon-doped InP contact layer is grown by Ipm.

Next, the disilane flow rate was reduced to 1 cc/min to form an InP collector layer (doping concentration n = 5 XIO” (!m
-') with a thickness of 0.5 μm.

When switching from InP growth to InGaAs growth, TMI and the dopant disilane are first switched to the vent line side, and then phosphine is switched to the vent line side.

Next, arsine is introduced into the thin film growth chamber through the raw material gas introduction line, and then TEG, TM, I, and the dopant diethylzinc are introduced to form an InGaAs base layer (doping concentration p = I XIOlgan-3) of 0.
Form 15 μm.

Next, similar gas flow paths were switched, and the Si-doped InP emitter layer (doping concentration n = 5 x 10
"rxi-") of 0.5 μm, and a Si-doped InGaAs contact layer (doping concentration n=4
IO "am-").

FIG. 11 shows the switching sequence of the gas flow path switching valve in the thin film growth described above.

In FIG. 11, "growth chamber" and "vent line" on the sequence line indicate that the source gas is introduced into the thin film growth chamber or the vent line, respectively.

FIG. 12 shows I produced by the conventional vapor phase growth technique.
n P / G a I n A s / I n P
A cross-sectional view of a double heterostructure bipolar transistor is shown, and FIG. 13 shows an energy band diagram of the same transistor.

In addition, as a technique related to this type of thin film forming method and apparatus, for example, Japanese Patent Application Laid-Open No. 62-232931 can be cited.

[Problem to be solved by the invention]

However, in the conventional thin film formation method using vapor phase growth, the raw material gas is flowed through the vent line at a flow rate set in advance by a mass flow controller.
At the start of thin film growth, the gas flow path switching valve is switched to open the source gas introduction line from the vent line, and the source gas is introduced from this source gas introduction line into the thin film growth chamber.

Therefore, by using this conventional technique, a thin film with a gradient composition in which the composition in the film thickness direction gradually changes, such as InxGa1-xA, can be produced.
In order to form 5yP□-y, the following method can be considered. That is, (1) To change the composition of group V elements, gradually shift the flow rate setting value of the mass flow controller.

(2) In order to change the composition of group (■) elements, the temperature of the raw material gas is gradually changed.

However, in current mass flow controllers, when the flow rate setting value is changed, hunting occurs in the flow rate, and it takes time for the flow rate to stabilize. Further, even if the temperature of the constant temperature bath is changed in order to change the temperature of the group (Ⅰ) element, it takes time for the raw material gas temperature to follow the temperature of the constant temperature bath.

For this reason, it is almost difficult to grow a thin film with a composition gradient in the film thickness direction using conventional vapor phase growth techniques.

On the other hand, in transistors manufactured using the conventional vapor phase growth technology, a spike in the conduction band appears at the emitter-base junction, as is clear from the energy band shown in Figure 13, which reduces the emitter injection efficiency. ing.

Furthermore, since the carriers travel in the base region by diffusion, the base travel time of the carriers occupies most of the total travel time within the device, which is a hindrance to increasing the speed of the device.

Therefore, in order to increase carrier injection efficiency, improve current gain, and increase speed, a gradient composition is introduced at the junction between the emitter layer and the base layer to eliminate spikes in the conduction band, and the base layer is It is necessary to use a gradient composition so that carriers injected into the base also move due to the electric field.

However, with conventional vapor phase growth techniques, it has been difficult to form films with gradient compositions.

A first object of the present invention is to provide a method for forming a thin film by vapor phase growth, which can easily form a thin film with a composition gradient in the film thickness direction.

A second object of the present invention is to provide a film that can form a plurality of thin films including a compound semiconductor thin film on the surface of a substrate, and at least one of the plurality of layers can be formed of a film having a composition gradient in the thickness direction. An object of the present invention is to provide a method for forming a thin film by phase growth.

A third object of the present invention is to provide a method for manufacturing a transistor by vapor phase growth in which the base layer and the junction between the base layer and the emitter layer can be easily formed using a film having a composition gradient in the film thickness direction. It is about providing.

Furthermore, a fourth object of the present invention is to provide a vapor phase growth apparatus that can accurately carry out the thin film forming method and transistor manufacturing method using vapor phase growth.

A fifth object of the present invention is to provide a vapor phase growth apparatus that can more effectively carry out the thin film forming method and transistor manufacturing method using vapor phase growth.

[Means to solve the problem]

The first objective is to increase the rate per unit time of at least one type of raw material gas reaching the substrate surface among a plurality of types of raw material gases injected onto the surface of a substrate installed in a thin film growth chamber placed under reduced pressure. This is achieved by gradually changing the amount of the other source gases that reach the substrate surface per unit time.

The second object is achieved by forming a plurality of layers of thin films including a compound semiconductor thin film on the surface of the substrate using a raw material gas containing elements constituting a compound semiconductor as the plurality of types of raw material gases.

The third purpose is to inject half of at least one type of raw material gas selected from among a plurality of types of raw material gases to be injected onto the surface of a semi-insulating semiconductor substrate placed in a thin film growth chamber placed under reduced pressure. The amount of gas that reaches the surface of the insulating semiconductor substrate per unit time is gradually changed relative to the amount of other source gases that reach the surface of the semi-insulating semiconductor substrate per unit time. This is achieved by forming the junction between the emitter layer and the emitter layer using a film having a composition gradient in the film thickness direction.

The fourth object is achieved by connecting each gas flow path switching valve provided at each of the plurality of raw material gas inlets to a control means that can individually change the opening/closing interval per unit time. .

The fourth object is also achieved by connecting each of the gas flow path switching valves to a control means that can individually change the opening time per unit time.

The fourth object is also achieved by providing a shutter at a position facing each of the raw material gas inlets, and by connecting each shutter to a control means that can individually change the opening/closing interval per unit time. .

The fourth object is also achieved by connecting each of the shutters to a control means that can individually change the opening time per unit time.

The fifth object is to connect each of the gas flow path switching valves to a control means that can individually change the opening/closing interval per unit time, to provide a shutter at a position facing each of the raw material gas inlets, and to This is achieved by connecting the shutter to a control means that can individually change the opening/closing interval per unit time, and by connecting the control means for the gas flow path switching valve and the shutter control means so as to be interlocked.

Further, the fifth object is to connect each of the gas flow path switching valves to a control means that can individually change the opening time per unit time, and to provide a shutter at a position facing each of the raw material gas inlets. , can also be achieved by connecting each shutter to a control means that can individually change the opening time per unit time, and also by connecting the control means for the gas flow path switching valve and the control means for the shutter so as to be interlocked. be done.

Furthermore, the fifth object can also be achieved by opening each of the raw material gas inlets toward the center of the substrate surface in the vapor phase growth apparatus.

[Effect]

In the thin film forming method of the present invention, a substrate is placed in a thin film growth chamber placed under reduced pressure. Then, a plurality of types of raw material gases are injected onto the surface of the substrate from the raw material gas inlet to cause vapor phase growth of a thin film. that time.

The amount of at least one source gas reaching the substrate surface per unit time is gradually changed relative to the amount of other source gases reaching the substrate surface per unit time.

As a result, the growth rate of a thin film using at least one type of raw material gas changes with respect to the growth rate of a thin film using other types of raw material gases, making it possible to easily form a thin film with a gradient composition in the film thickness direction. .

Further, in the thin film forming method of the present invention, a plurality of types of source gases include source gases containing elements constituting a compound semiconductor. The source gas is injected onto the surface of the substrate, and one of the plurality of types of source gases.

By gradually changing the amount of at least one type of raw material gas that reaches the substrate surface per unit time relative to the amount of other raw material gases that reach the substrate surface per unit time, A plurality of thin film layers can be formed, and at least one layer can be formed with a film having a composition gradient in the film thickness direction.

In the method for manufacturing a transistor according to the present invention,
A semi-insulating semiconductor substrate is placed in a thin film growth chamber. Next, a plurality of types of raw material gases are injected onto the surface of the semi-insulating semiconductor substrate from a plurality of raw material gas inlets to form a J-stop collector layer, a base layer, and an emitter layer. At that time, the amount of at least one of the plurality of raw material gases reaching the surface of the semi-insulating semiconductor substrate per unit time is calculated by comparing the amount of the other raw material gas reaching the surface of the semi-insulating semiconductor substrate per unit time. At least the base layer and the junction between the base layer and the emitter layer are
The film is formed with a composition gradient in the film thickness direction. As a result, at least the base layer and the junction between the base layer and the emitter layer.

It can be formed with layers of graded composition, which can significantly improve the performance of the transistor.

Furthermore, in the vapor phase growth apparatus of the present invention, a plurality of raw material gas inlets are provided in the thin film growth chamber, and a raw material gas inlet line and a vent line are connected to each raw material gas inlet via a gas flow path switching valve. , each of the gas flow path switching valves is connected to a control means that can individually change the opening/closing interval per unit time.

therefore.

The opening/closing interval per unit time of at least one gas passage switching valve selected from the plurality of gas passage switching valves is changed with respect to the opening/closing interval per unit time of the other gas passage switching valves, and at least one type of gas passage switching valve is changed. The amount of the source gas reaching the substrate surface per unit time can be gradually changed with respect to the amount of other source gases reaching the substrate surface per unit time.

This makes it possible to change the growth rate of the thin film using at least one type of source gas, making it possible to form a thin film with a composition gradient in the film thickness direction.

Furthermore, in the vapor phase growth apparatus of the present invention, each of the gas flow path switching valves is connected to a control means that can individually change the opening time per unit time. As a result, the opening time per unit time of at least one gas flow switching valve selected from among the plurality of gas flow switching valves is changed to the opening time per unit time of the other gas flow switching valves. As a result, the amount of at least one source gas reaching the substrate surface per unit time can be gradually changed relative to the amount of other source gases reaching the substrate surface per unit time. can be changed to

Further, in the vapor phase growth apparatus of the present invention, a shutter is provided in front of each of the raw material gas inlets, and each shutter is connected to a control means that can individually change the opening/closing interval per unit time. As a result, the opening/closing interval per unit time of at least one shutter selected among the plurality of shutters can be changed with respect to the opening/closing interval per unit time of the other shutters, thereby at least The amount of one type of source gas reaching the substrate surface per unit time can be gradually changed with respect to the amount of other source gases reaching the substrate surface per unit time.

Furthermore, in the vapor phase growth apparatus of the present invention, each shutter is connected to a control means that can individually change the opening time per unit time. As a result, among the multiple shutters,
The opening time per unit time of the selected at least one shutter can be varied with respect to the opening time per unit time of the other shutters, thereby making it possible to change the opening time per unit time of the at least one shutter.
The amount of one type of source gas reaching the substrate surface per unit time can be gradually changed with respect to the amount of other source gases reaching the substrate surface per unit time.

Further, the vapor phase growth apparatus of the present invention is provided, wherein each of the gas flow path switching valves is connected to a control means that can individually change the opening/closing interval per unit time, and a shutter is provided in front of each of the raw material gas inlets. , each shutter is connected to a control means that can individually change the opening/closing interval per unit time, and the control means for the gas flow path switching valve and the control means for the shutter are connected so as to be interlocked. As a result, the opening/closing interval per unit time of at least one selected gas passage switching valve out of the plurality of gas passage switching valves and the opening/closing interval per unit time of the shutter are changed from those of the other gas passage switching valves. It is possible to change the opening/closing interval per unit time of the gas flow path switching valve and the shutter, so that the amount of at least one source gas reaching the substrate surface per unit time can be changed from the amount of other source gases reaching the substrate surface. It is possible to gradually change the amount reached per unit time.

Furthermore, in the vapor phase growth apparatus of the present invention, each of the gas flow path switching valves is connected to a control means that can individually change the opening time per unit time, and a shutter is provided in front of each of the raw material gas inlets. , each shutter.

It is connected to a control means that can individually change the opening time per unit time, and the control means for the gas flow path switching valve and the control means for the shutter are connected so as to be interlocked. As a result, the opening time per unit time of at least one gas flow switching valve selected from among the plurality of gas flow switching valves and the opening time per unit time of the shutter are changed from those of the other gas flow switching valves. The opening time per unit time of the gas flow path switching valve and shutter can be changed, so that the amount of at least one source gas reaching the substrate surface per unit time can be changed from the amount of other source gases reaching the substrate surface. It is possible to gradually change the amount reached per unit time.

Furthermore, in the vapor phase growth apparatus of the present invention, each source gas inlet is opened so that the source gas can be injected toward the center of the surface of the substrate installed in the thin film growth chamber.

On the other hand, the gas atmosphere during thin film growth in the thin film growth chamber is normally controlled to 1X10-2 Torr or less.

As a result, each of the raw material gas inlets was opened so that the raw material gas could be injected toward the center of the surface of the substrate, and the interior of the thin film growth chamber was as described above.
Coupled with the fact that the gas atmosphere is controlled to be below rr, there is almost no convection or turbulence of the raw material gas in the thin film growth chamber, and therefore a thin film with excellent quality can be formed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a vapor phase growth apparatus for forming a thin film for carrying out the method of the present invention, and FIG. 2 is a block diagram showing an example of a gas flow path switching valve, a shutter, and means for controlling these. FIG. 3 shows an example of the shutter, and is a side view seen from the axial direction.

The vapor phase growth apparatus for thin film formation of the embodiment shown in these figures has a thin film growth chamber 30 as shown in FIG.

A pressure adjustment container 31, and conductance adjustment valves 32a and 32b are provided in the thin film growth chamber 30 and the pressure adjustment container 31.
Exhaust pumps 33a, 33b connected via
4, an acetator 35 provided in the thin film growth chamber 30 and to which the substrate 36 is attached, and raw material gas sources 37a to 37d.
, raw material gas introduction lines 38a to 38d, mass flow controllers 39a to 39d provided in each raw material gas introduction line 38a to 38d, and each raw material gas introduction line 38
a to 38d and opening into the thin film growth chamber 30, and source gas introduction ports 40a to 40d, which are provided corresponding to the respective source gas introduction lines 38a to 38d and connected to the pressure adjustment vessel 31. Commonly connected vent lines 41a to 41d and the flow of raw material gas are connected to raw material gas inlets 40a to 40d or vent lines 41a to 41d.
Gas flow path switching valves 42a to 42d that switch to
Shutters 43a to 43d provided at positions facing d
, a high-frequency coil (not shown) for heating the substrate, and control means for a gas flow path switching valve and a shutter.

In the embodiment shown in FIG. 1, arsine (A s H3) is supplied from the raw material gas source 37a, phosphine (PH3) is supplied from the raw material gas source 37b, and TE is supplied from the raw material gas source 37c.
G, and trimethylaluminum [(CH3), AQ] (hereinafter referred to as "TMAJ") are supplied from the raw material gas source 37d.

The raw material gas inlets 40a to 40d are provided so as to be able to inject the raw material gas through the susceptor 35 toward the center of the surface of the substrate 36 installed in the thin film growth chamber 30, respectively.

In FIG. 2, the raw material gas introduction line is designated by 38, the raw material gas inlet is designated by 40, the vent line is designated by 41, and the gas flow path switching valve is designated by 42.
Further, in FIGS. 2 and 3, the shutter is designated by the reference numeral 43.
Each is shown as a representative.

As shown in FIGS. 2 and 3, the shutter 43 has a semicircular first. It includes second blades 44 and 45, dual inner and outer drive sections 46, and a shutter drive section 47.

Said 1st. One of the second blades 44 , 45 is connected to one of the inner and outer drive parts 46 , and the other blade is connected to the other of the drive parts 46 .

Said 1st. As shown in FIG.
The three shutter drive sections 47, which are arranged at a distance of about 10a++++, are connected to the first shutter drive section 47 through a double drive section 46. The second blades 44, 45 are opened and closed. Further, this shutter drive section 47 has a substantially semicircular first section. By adjusting the overlapping angle of the second blades 44, 45, in this embodiment, as can be seen from FIG. 3, the opening degree can be adjusted in the range of 0 to 180 degrees.

And the above-mentioned 1. By rotating the entire second blade 44, 45 around the vibration rod 46, the position can be adjusted so that the opening of the shutter 43 fits into the source gas inlet 40.

The gas flow path switching valve 42 includes a first. Second drive valve 48
．． 49 are provided. The gas flow path switching valve 42 is connected to the raw material gas introduction line 38-yX from the first drive valve No. 48.
The source gas inlet 40 side is switched to open, and the second drive valve 49 switches the gas flow path switching valve 42 to the source gas inlet line 3.
8-Vent line 41 side can be opened.

The gas flow path switching valve and shutter control means includes a second
As shown in the figure, a shutter controller 50, a valve controller 51, a solenoid valve 53 provided between the shutter drive section 47 and the shutter controller 50, and the first... Second drive valve 48, 49 and valve controller 5
1. Solenoid valves 54 and 55 provided between the shutter drive section 47 and the first. A fluid pressure supply system 56 that supplies fluid pressure such as compressed air to the second drive valves 48 and 49 is provided.

A microcomputer or a sequencer is used for the shutter controller 50 and the valve controller 51, and the respective operation sequences can be repeatedly operated at intervals of, for example, 0.1 seconds. In this embodiment, the shutter controller 50 and the valve controller 51 are configured to independently open and close the shutter 43 and the gas flow path switching valve 42, respectively.

The solenoid valve 53 opens in response to a shutter open signal from the shutter controller 50, sends fluid pressure to the shutter drive unit 47 through a fluid pressure supply system 56, opens the shutter 43, and opens in response to a shutter close signal from the shutter controller 50. When the solenoid valve 53 closes, the shutter 43 closes.

The solenoid valves 54 and 55 open the solenoid valve 54 and close the solenoid valve 55 in response to a switching valve opening signal from the valve controller 51, and when the solenoid valve 54 opens, the fluid pressure supply system 56 releases the gas passage switching valve 42. Fluid pressure is supplied to the first drive valve 48, and the gas flow path switching valve 42 is switched to open the source gas introduction line 38-source gas inlet 40 side.

Further, a switching valve close signal from the valve controller 51 opens the solenoid valve 55 and closes the solenoid valve 54.
When the valve is opened, fluid pressure is supplied from the fluid pressure supply system 56 to the second driving valve 49 of the gas flow switching valve 42, and the gas flow switching valve 4 is opened.
2 can be switched to open the source gas introduction line 38-pento line 41 side.

Further, in this embodiment, the gas flow path switching valve 42 is opened and closed, but it may be possible to open and close the valve and adjust the degree of opening.

In this embodiment, as shown in FIG. 2, the thin film growth chamber 30 and the source gas inlet 40 are a flange 57 provided in the thin film growth chamber 30 and an ICF flange 58 provided in the source gas inlet 40. Vacuum-sealed through connection with Further, the thin film growth chamber 30 and the first shutter 43 are The drive unit 46 of the second blade 44.45 is the thin film growth chamber 30.
The flange 59 provided on the drive portion 46 is vacuum-sealed through contact with the flange 60 provided on the drive portion 46 .

In this embodiment, prior to vapor phase growth of a thin film, the inside of the thin film growth chamber 30 shown in FIG. 1 is evacuated by an exhaust pump 33a,
Moreover, the degree of vacuum is maintained at 1X10-2 orr or less set by the conductance adjustment valve 32a. Also,
The inside of the compression regulator 31 is also evacuated by the exhaust pump 33b, the degree of vacuum is set by the conductance adjustment valve 32b,
The vacuum level is maintained at the same level as the thin film growth chamber 30.

The degree of vacuum in the thin film growth chamber 30 is I x 10-''
Torr or less, and as can be seen from FIG. 1, each source gas inlet 40a to 40d is provided so as to open toward the center of the surface of the substrate 36, The source gas injected from the substrate 36 travels straight toward the center of the surface of the substrate 36, and no convection or turbulence of the source gas occurs within the thin film growth chamber 30.

Figure 5 shows the situation in which the ion chamber of a quadrupole mass spectrometer (QMA) is placed at the same location as the substrate, and the source gas flow is blocked by the gas flow path switching valve and shutter.
The results of the investigation are shown below.

If both the gas flow switching valve and the shutter cut off the raw material gas at 0.1 seconds or less, the sag at the membrane interface due to opening and closing of the gas flow switching valve and shutter can be ignored. Therefore, the opening/closing interval per unit time of the selected gas passage switching valve and shutter out of the plurality of gas passage switching valves and shutters is set to the opening/closing interval per unit time of the other gas passage switching valves and shutters. By changing the spacing, the amount per unit of the source gas injected from the selected source gas inlet that reaches the substrate surface can be changed to the amount that the source gas injected from the other source gas inlets reaches the substrate surface. The amount reached per unit can be changed, and as a result, the growth rate of the thin film by the source gas can be changed. For example, if Ga As is 500
When forming at a growth rate of 0 people/hour, Ga and As
The time required to grow each layer of is approximately 2 seconds, so by changing the opening/closing interval every 0.1 seconds, with 2 seconds as one cycle, the growth rate can be increased from O to 5,000 people/hour. It can be changed between. Therefore, for example, in order to change the film thickness of A Q x Ga Ne x As, it is sufficient to change the growth rates of GaAs and A Q A s in different modes.

In the vapor phase growth apparatus of this embodiment, the opening/closing interval per unit time can be changed for all of the gas flow path switching valves 42a to 42d and shutters 43a to 43d shown in FIG. By changing the opening/closing interval per unit time of the gas flow path switching valve and the shutter, the composition in the thickness direction of the thin film having a mixed crystal composition can be easily changed.

Furthermore, the opening time per unit time of the selected gas flow switching valve and shutter out of the plurality of gas flow switching valves and shutters is compared to the opening time per unit time of the other gas flow switching valves and shutters. Even if the composition is changed over time, a thin film with a gradient composition in the film thickness direction can be formed.

Next, FIG. 4 shows another embodiment of the vapor phase growth apparatus of the present invention, and is a block diagram showing a gas flow path switching valve and shutter control means.

In the gas flow path switching valve and shutter control means in the embodiment shown in FIG. 4, a shutter controller 50 and a valve controller 51 are connected by a signal line 52,
The opening/closing operation of the shutter 43 and the switching operation of the gas flow path switching valve 42 are made to be linked. Another configuration of the embodiment shown in FIG.

The operation is similar to that of the embodiment shown in FIG. 2 above.

(Example 1) This Example 1 is an example in which a GaAs/AuxGa1-xAs film (X varies from O to 0.2) is grown.

In advance, the inside of the thin film growth chamber 30 and the inside of the pressure adjustment container 31 are heated to lXl0-'T using the exhaust pumps 33a and 33b.
Evacuate to a vacuum level below orr.

Next, the GaAs substrate 36 is introduced into the thin film growth chamber 30 using a load lock mechanism (not shown).

Next, similar to the CVD device, a high frequency coil (not shown) is installed.
The GaAs substrate 36 is heated to a thin film growth temperature of 600°C.

In addition, arsine (A s H,),
TEG.

supply TMA and mass flow control cola 39 respectively.
a, 39c, 39d to control the flow rate, 2c per minute
c.

0.5cc, 0.2cc into the raw material gas introduction line 38
a, 38c.

38d and gas flow path switching valves 42a, 42c,
Vent lines 41a, 41c, through 42d
Let it flow to 41d.

To avoid thermal damage to the surface of the GaAs substrate 36 when the substrate temperature rises, the shutter 43a is opened and the gas flow path switching valve 42a is closed.
ti-raw material gas introduction line 38a-raw material gas inlet 40
Switching to the a-side opening, arsine is injected onto the surface of the GaAs substrate 36.

The surface temperature of the GaAs substrate 36 is the thin film growth temperature of 500°C.
After the temperature is stabilized, the shutter 43c is opened, the gas flow path switching valve 42c is switched to the source gas introduction line 38c-source gas inlet 40c side, and a T is applied to the surface of the GaAs substrate 36.
EG is injected to start the growth of GaAs. The pressure in the thin film growth chamber 30 at this time is 5X10-' Torr, and the mean free path of the source gas molecules is equal to the source gas inlet 40c.
Distance from the surface of the Ga As substrate 36 to 14 cm
Since the length is longer than that, there is no disturbance of the raw material gas due to convection or turbulence in the thin film growth chamber 30, and a good film thickness distribution is obtained.

After growing 5,000 pieces of GaAs in one hour, the gas flow switching valve 42d is switched to open the source gas introduction line 38d-source gas inlet 40d side. At this time, one cycle of the opening and closing of the shutter 43ci is 2 seconds, and the shutter open time is increased every 5 seconds in steps of 0.05 seconds.
After 00 seconds, the shutter 43d remained open.

This changed the AQ ratio from 0 to 0.2.

An AAxGa kneexAs film having a composition gradient in the film thickness direction was obtained.

Next, FIG. 6 is a block diagram showing another embodiment of a vapor phase growth apparatus for forming a thin film for carrying out the method of the present invention.

The vapor phase growth apparatus shown in FIG. 6 is the same as that shown in FIG.
9e, 39f, source gas inlets 40e, 40f, vent lines 41e, 41f, gas flow path switching valve 42e,
The vapor phase growth apparatus is the same as the vapor phase growth apparatus shown in FIG. 1, except that 42f and shutters 43e and 43f are added.

Next, FIG. 7 shows Gax I which is lattice matched to the InP substrate.
Composition diagram of n, -xAs, -yP Y quaternary mixed crystal, FIG. 8 is a schematic diagram of a transistor formed by the vapor phase growth apparatus of the present invention, and FIG. 9 is a composition diagram of a transistor formed by the vapor phase growth apparatus of the present invention. FIG. 2 is an energy band diagram of a transistor.

Next, a method of manufacturing a transistor by a vapor phase growth method using the vapor phase growth apparatus shown in FIG. 6 will be described.

(Example 2) In this Example 2, InP/InGaAs shown in FIG.
A method for manufacturing a (P)/InPIn hetero bipolar transistor will be described.

In advance, the inside of the thin film growth chamber 30 and the pressure adjustment vessel 31 are heated to lX10-'' set by the conductance adjustment valves 32a and 32b using the exhaust pumps 33a and 33b.
Evacuate to a vacuum level below Torr.

Next, the InP substrate 36 is introduced into the thin film growth chamber 30 using a load lock mechanism (not shown).

Next, the InP substrate 36 is heated to a thin film growth temperature of 500° C. using a high frequency coil (not shown).

Further, as the raw material gas, raw material gas sources 37 a, 37
b.

Arsine, phosphine, TEG, TEI, disilane (Si2
HG) and diethyl zinc (DEZn) respectively through mass flow controllers 39a, 39b, 39c.
lee per minute by , 39d, 39e and 39f
, 2cc, 0.5cc, 0.6cc, 0.2c
The flow rates are controlled to 0 and 2 cc, and the raw material gas introduction lines 38a, 38b, 38c, 38d,
Vent lines 41a, 41 from 38e and 38f
b, 41c, 41d, 41e and 41f
Let it flow.

In order to avoid thermal damage to the surface of the InP substrate 36 when the temperature of the InP substrate 36 increases, the shutter 43b is opened, the gas flow path switching valve 42b is switched to the source gas introduction line 38b-source gas inlet 40b side open, and the InP substrate 36 is heated. Phosphine is injected onto the surface of 36.

After the temperature of the InP substrate 36 stabilizes at the thin film growth temperature of 500°C, the shutters 43d and 43e are opened, and the gas flow path switching valves 42d and 42e are connected to the source gas introduction line 3.
8d - Switching to open the source gas inlet 40d side and open the source gas inlet line 38e - source gas inlet 40e side, and connect the InP substrate 3 from the source gas inlets 40d and 40c.
Inject TEI and disilane onto the surface of n-type In
Start the growth of P. The pressure inside the thin film growth chamber 30 at this time is I x 10-' Torr. At this time, since the mean free path of the source gas molecules is longer than the distance 18C11 from the source gas inlet to the surface of the InP substrate 36, there is no disturbance of the source gas due to convection or turbulence in the thin film growth chamber 30, and a good condition is achieved. Film thickness, carrier concentration, and composition distribution were obtained.

After growing 3000 InP, the composition changed from InP to I n O, 53G a 0.47A s in the first 300 people.
7, gas flow path switching valves 42a, 42b, 42c and 4 are installed so that the composition changes according to the solid line shown in FIG.
2d from the raw material gas introduction line 38a to the raw material gas inlet 4
0a side opened.

Source gas introduction line 38b - source gas inlet 40b side open, source gas introduction line 38c - source gas inlet 40c
Switching to side opening and source gas introduction line 38d - source gas inlet 4Od side opening, source gas inlets 40a, 40b, 40s and 40d in thin film growth chamber 30.
Through arsine, phosphine, TEG, and TEG
will be introduced.

At this time, the shutter control changes the opening/closing time in 0.1 second steps, with 3 seconds as one period of shutter opening/closing. Then, the opening time of the phosphine shutter 43b is successively reduced by 0.1 seconds starting from 3 seconds, so that it will not open after 90 seconds. In addition, the shutter 43a of Alsin and TEG
and 43c, contrary to the shutter 43b, increases the opening time by 0.1 seconds from the completely closed state, and 90
Leave it open after a few seconds. Further, the TEI shutter 43d remains open during this time. Meanwhile, each gas flow path switching valve 42a, 42b, 42c and 42
d is not switched. This completes the growth of the collector layer and moves on to the growth of the base layer.

When growing the base layer, first use the disilane shutter 4.
3a is closed, the gas flow path switching valve 42e is switched to open the source gas introduction line 38e-vent line 41e side, and disilane is introduced into the pressure regulating container 31.

Thereafter, the diethyl zinc shutter 43f is opened and the gas flow path switching valve 42f is switched to open on the source gas introduction line 38f-source gas inlet 4Of side to introduce diethyl zinc into the thin film growth chamber 30.

Since the base layer also has a diagonal composition in which the composition changes from InO, 53G a O, and 47A s to InP, growth is performed using the reverse shutter sequence when growing the coreft layer described above. Since the number of people in the base layer is 1,200, one period of opening and closing of the shutter will be 12 seconds, and the opening and closing interval will be changed every 0.1 seconds.

When the growth of the base layer is completed, the arsine and TEG shutters 43a and 43c are closed.

Since the gas flow path switching valves 42a and 42c are open, first switch the gas flow path switching valves 42a and 42c to open the source gas introduction line 38a-vent line 41a side and open the source gas introduction line 38cm vent line 41c side, Arsine and TEG are introduced into the pressure regulating vessel 31. Also, close the diethyl zinc shutter 43f, close the gas flow path switching valve 42f, and close the raw material gas introduction line 38f.
- Switch to open the vent line 41f side and introduce diethyl zinc into the pressure adjustment container 31.

Next, the disilane shutter 43e is opened again, the gas flow path switching valve 42e is switched to open the source gas introduction line 38e-source gas inlet 4Oe side, and the source gas inlet 40e is opened.
Disilane is injected onto the surface of the InP substrate 36 to start growing the Si-doped InP emitter layer, and the Si-doped InP emitter layer is grown.
When 3000 P emitter layers have grown, all the shutters are closed and the film formation for the bipolar transistor is completed.

In this way, by introducing a gradient composition in the film thickness direction between the collector base and between the emitter base,
As is clear from the energy band diagram shown in Figure 9, the protrusion of the conduction band at the interface of these layers is eliminated, improving the emitter injection efficiency and eliminating the energy gap between the base and collector. can. Further, by making the base layer have a graded composition, an internal electric field can be provided, thereby accelerating electrons and shortening the base transit time of electrons.

The characteristics of the transistor formed by the above vapor phase growth are that the current gain is 300. Good results were obtained with a current density of 1.4 kA/-.

In Example 2 described above, InP/InGaAs(P
) system crystal growth has been described, but the vapor phase growth method according to the present invention can also be used for the growth of other ■-■ group and ■-■ group compound semiconductor crystals.

Further, in the second embodiment, a method for manufacturing a transistor has been described, but the present invention can also be applied to a method for manufacturing a photodetector or a laser diode.

In addition, in each of the above embodiments, the case of metal organic vapor phase epitaxy method was described, but it is also applicable to the case of vapor phase epitaxy method using other raw material gas species such as hydride vapor phase epitaxy method or chloride vapor phase epitaxy method. Applicable.

Furthermore, in addition to vapor phase growth of compound semiconductors, we also
It can also be used for vapor phase growth of elemental semiconductors such as e and their mixed crystals. Furthermore, it can also be applied to various CVD growth methods such as SiC2, SI, N, etc.

〔Effect of the invention〕

According to the invention described in claim 1 of the present invention described above, the amount of at least one type of raw material gas reaching the substrate surface per unit time among the plurality of types of raw material gases is determined by the amount of other raw material gases reaching the substrate surface. Since the amount reaching the surface per unit time is gradually changed, the growth rate of a thin film using at least one type of source gas is higher than the growth rate of a thin film using other types of source gas. This has the effect of easily forming a thin film with a composition gradient in the film thickness direction.

According to the second aspect of the present invention, the plurality of raw material gases include a raw material gas containing an element constituting a compound semiconductor, the raw material gas is injected onto the surface of the substrate, and the plurality of raw material gases are injected onto the surface of the substrate. The amount of at least one of the source gases reaching the substrate surface per unit time is gradually changed relative to the amount of other source gases reaching the substrate surface per unit time. Therefore, it is possible to form a plurality of thin films including a compound semiconductor thin film, and at least one layer has the effect of forming a film having a composition gradient in the film thickness direction.

Furthermore, according to the third aspect of the present invention, the amount of at least one of the plurality of raw material gases reaching the surface of the semi-insulating semiconductor substrate per unit time is determined by the amount of the other raw material gases reaching the surface of the semi-insulating semiconductor substrate. The amount of gas reaching the semi-insulating semiconductor substrate surface per unit time is varied, and at least the base layer and the junction between the base layer and the emitter layer are formed of a film with a composition gradient in the film thickness direction. I try to do this, so
At least the base layer and the junction between the base layer and the emitter layer can be formed of a layer with a graded composition, which has the effect of significantly improving the performance of the transistor.

Further, according to the fourth aspect of the present invention, a plurality of source gas inlets are provided in the thin film growth chamber, and each source gas inlet is connected to a source gas inlet line and a vent line through a gas flow path switching valve. and each gas flow path switching valve is connected to a control means that can individually change the opening/closing interval per unit time, and at least one gas flow path switching valve selected from the plurality of gas flow path switching valves is connected. The opening/closing interval per unit time of the valve is changed with respect to the opening/closing interval per unit time of other gas flow path switching valves, and the amount of at least one type of source gas reaching the substrate surface per unit time is adjusted to Since the amount of the source gas reaching the substrate surface per unit time can be gradually changed, the thin film forming method and the transistor manufacturing method described above can be carried out accurately.

Furthermore, according to the invention set forth in claim 5 of the present invention, each of the gas passage switching valves is connected to a control means that can individually change the opening time per unit time, and the plurality of gas passages The opening time per unit time of at least one selected gas passage switching valve of the switching valves can be changed with respect to the opening time per unit time of the other gas passage switching valves, As a result, the amount of at least one source gas reaching the substrate surface per unit time can be gradually changed relative to the amount of other source gases reaching the substrate surface per unit time. This has the advantage that thin film forming methods and transistor manufacturing methods can be carried out accurately.

Furthermore, according to the sixth aspect of the present invention, a shutter is provided in front of each of the raw material gas inlets, and each shutter is connected to a control means that can individually change the opening/closing interval per unit time. and one of the multiple shutters
The opening/closing interval per unit time of the selected at least one shutter can be changed with respect to the opening/closing interval per unit time of the other shutters, thereby reducing the unit of at least one type of source gas reaching the substrate surface. Since the amount reached per unit time can be gradually changed relative to the amount reached per unit time of other source gases reaching the substrate surface, the thin film forming method and transistor manufacturing method described above can be carried out accurately. effective.

Further, according to the seventh aspect of the present invention, each of the shutters is connected to a control means that can individually change the opening time per unit time, and the shutter is selected from among the plurality of shutters. The opening time per unit time of at least one shutter can be changed with respect to the opening time per unit time of the other shutters, so that the opening time per unit time of at least one type of source gas reaching the substrate surface can be changed. Since the amount of gas that reaches the substrate surface can be gradually changed with respect to the amount of other source gases that reach the substrate surface per unit time, it is possible to accurately implement the thin film forming method and transistor manufacturing method. be.

Furthermore, according to the invention described in claim 8 of the present invention, each of the gas flow path switching valves is connected to a control means that can individually change the opening/closing interval per unit time, and and each shutter is connected to a control means that can individually change the opening/closing interval per unit time, and the control means for the gas flow path switching valve and the shutter control means are connected so as to be interlocked. The opening/closing interval per unit time of at least one selected gas passage switching valve among the plurality of gas passage switching valves and the opening/closing interval per unit time of the shutter are determined based on the opening/closing interval per unit time of the selected gas passage switching valve. The opening/closing interval per unit time of the flow path switching valve and shutter can be changed, so that the amount of at least one source gas reaching the substrate surface per unit time can be changed to the amount of other source gas reaching the substrate surface. Since the amount reached per unit time can be gradually changed, there is an effect that the thin film forming method and the transistor manufacturing method described above can be carried out even better.

Further, according to the ninth aspect of the present invention, each of the gas flow path switching valves is connected to a control means that can individually change the opening time per unit time, and and each shutter is connected to a control means that can individually change the opening time per unit time, and the control means for the gas flow switching valve and the shutter control means are connected so as to be interlocked. The opening time per unit time of at least one selected gas flow switching valve out of the plurality of gas flow switching valves and the opening time per unit time of the shutter are calculated based on the opening time per unit time of the selected five gas flow switching valves and the opening time per unit time of the shutter. The opening time per unit time of the flow path switching valve and shutter can be changed, so that the amount of at least one source gas reaching the substrate surface per unit time can be changed to the amount of other source gas reaching the substrate surface. Since the amount reached per unit time can be gradually changed, there is an effect that the thin film forming method and the transistor manufacturing method described above can be carried out even better.

According to the tenth aspect of the present invention, each source gas inlet is opened so that the source gas can be injected toward the center of the surface of the substrate installed in the thin film growth chamber, - The gas atmosphere during thin film growth in the decidual growth chamber is usually controlled to be below l First, it is possible to form a thin film with excellent quality, so that the thin film forming method and the transistor manufacturing method described above can be carried out even better.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a vapor phase growth apparatus for carrying out the method of the present invention, FIG. 2 is a block diagram showing an example of a gas flow path switching valve, a shutter, and means for controlling these, and FIG. This shows an example of the shutter, and is a side view seen from the axial direction. Figure 4 is a block diagram showing another example of the gas flow path switching valve, the shutter, and their control means. Figure 5 is the gas flow path switching valve. and signal strength change diagram when examining the blocking status of Asz” with the opening and closing of the shutter using a quadrupole mass spectrometer (QMA).
FIG. 6 is a block diagram showing another example of a vapor phase growth apparatus for carrying out the method of the present invention, and FIG. 7 shows Ga x I n -xAs lattice-matched to an InP substrate. ypy quaternary mixed crystal, FIG. 8 is a schematic structural diagram of a transistor manufactured by the method of the present invention, and FIG. 9 is an energy band diagram of the same transistor. FIG. 10 is a block diagram showing a conventional vapor phase growth apparatus.
Fig. 1 is a time chart showing the switching sequence of the gas flow path switching valve of the same vapor phase growth apparatus, and Fig. 12 shows 30... thin film growth chamber, 31... pressure adjustment vessel, 33a, 3
3b... Exhaust pump, 35... Susceptor, 36... Board, 37a~
37f... Raw material gas source, 38. 38a to 38f... Raw material gas introduction line, 39a
~39f...Mass flow controller, 40, 40a
~40f... Raw material gas inlet, 41.41a~41f.
...Vent line, 42, 42a to 42f...Gas flow path switching valve, 43, 43a to 43f-shi+7ri,
44, 45... shutter 1st. Second feather, 46.
... Drive rod, 47... Shutter drive section. 48, 49...the first gas flow path switching valve. Second driven valve. 50...Shutter controller, 51...Valve controller, 52...Signal line, 53.54.55...
Solenoid valve, 56...fluid pressure supply system.躬1 44 Ja-tM--Sq-r9 5th Otsu 51/No V Ruako>) II)-U61/-2L body 4 verse sway 1st Kunimuguchi G11x Jn+-x to S+-IFynMLE'x. Tsumugi and mouth first country grudge No. 0 Kuchisei kumu 1 Usukun 12 Sen 2 Bu- ℃”shi No. 3 1 giant’! ! It

Claims (1)

[Claims] 1. A plurality of types of raw material gases are injected from a raw material gas inlet opening into a thin film growth chamber placed under reduced pressure onto the surface of a substrate installed in the thin film growth chamber to form a vapor phase. In the thin film forming method of forming a thin film on the surface of the substrate by growth, the amount of at least one of the plurality of types of source gases reaching the substrate surface per unit time is determined by controlling the amount of the other source gases reaching the substrate surface per unit time. A method for forming a thin film by vapor phase growth, which is characterized by gradually changing the amount that reaches the substrate surface per unit time. 2. The vapor phase according to claim 1, characterized in that a plurality of types of source gases are source gases containing elements constituting a compound semiconductor, and a plurality of layers of thin films including a compound semiconductor thin film are formed on the surface of the substrate. Method of forming thin films by growth. 3. Multiple types of raw material gases are injected from the raw material gas inlet opening into the thin film growth chamber under reduced pressure onto the surface of the semi-insulating semiconductor substrate installed in the thin film growth chamber, and the vapor phase growth is performed. In the method for manufacturing a transistor in which a collector layer, a base layer, and an emitter layer are sequentially formed on the surface of the semi-insulating semiconductor substrate, of the plurality of raw material gases,
The amount of at least one selected source gas reaching the surface of the semi-insulating semiconductor substrate per unit time is gradually increased relative to the amount of other source gases reaching the surface of the semi-insulating semiconductor substrate per unit time. A method for manufacturing a transistor by vapor phase growth, characterized in that at least the base layer and the junction between the base layer and the emitter layer are formed with a film having a composition gradient in the film thickness direction. 4. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting raw material gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a raw material gas introduction line and a vent line connected via gas flow switching valves, each gas flow switching valve is controlled to individually change the opening/closing interval per unit time. A vapor phase growth apparatus characterized in that it is connected to means. 5. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting source gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a source gas introduction line and a vent line connected via gas flow switching valves, each gas flow switching valve is controlled to individually change the opening time per unit time. A vapor phase growth apparatus characterized in that it is connected to means. 6. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting source gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a raw material gas introduction line and a vent line connected via a gas flow path switching valve, a shutter is provided at a position facing each of the raw material gas inlets, and each shutter is operated at a rate per unit time. 1. A vapor phase growth apparatus, characterized in that the vapor phase growth apparatus is connected to a control means that can individually change the opening/closing interval of the vapor phase growth apparatus. 7. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting raw material gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a raw material gas introduction line and a vent line connected via a gas flow path switching valve, a shutter is provided at a position facing each of the raw material gas inlets, and each shutter is operated at a rate per unit time. A vapor phase growth apparatus characterized in that the apparatus is connected to a control means that can individually change the opening time of the apparatus. 8. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting source gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a raw material gas introduction line and a vent line connected via gas flow switching valves, each gas flow switching valve is controlled to individually change the opening/closing interval per unit time. A shutter is provided at a position facing each of the source gas inlets, and each shutter is connected to a control means that can individually change the opening/closing interval per unit time. A vapor phase growth apparatus characterized in that a control means and a shutter control means are connected in an interlocking manner. 9. A thin film growth chamber in which a substrate is installed, an exhaust means connected to this thin film growth chamber, a plurality of source gas inlets for injecting source gas into the thin film growth chamber, and a plurality of source gas inlets for each source gas inlet. In a vapor phase growth apparatus equipped with a source gas introduction line and a vent line connected via gas flow switching valves, each gas flow switching valve is controlled to individually change the opening time per unit time. A shutter is provided at a position facing each of the source gas inlets, each shutter is connected to a control means that can individually change the opening time per unit time, and the gas flow path switching valve is A vapor phase growth apparatus characterized in that a control means and a shutter control means are connected in an interlocking manner. 10. The vapor phase growth apparatus according to claim 4, wherein each of the raw material gas inlets is opened toward the center of the substrate surface.