JP2951769B2 - Vapor phase growth equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for vapor-phase growing a thin film such as an amorphous silicon thin film which is a material for an amorphous silicon solar cell or an amorphous silicon thin film transistor on a substrate surface. A gas decomposition heater unit provided with a gas heater for heating and decomposing a compound gas containing thin film components, which is introduced into a reaction tank for forming a thin film, and a substrate heater for keeping a substrate at a predetermined high temperature. The present invention relates to a configuration of a vapor growth apparatus provided.

[0002]

2. Description of the Related Art Recently, the field of application of thin films has been expanding, especially in the semiconductor industry. Such thin films include amorphous silicon, polycrystalline silicon, silicon oxide, and silicon nitride. In general, a thin film is manufactured using a CVD technique, in which dissociation energy is applied to a compound gas as a raw material to deposit a thin film having an intended composition composed of decomposition products. For example, as a method for producing an amorphous silicon-based thin film, gas molecules of a silane-based source gas are excited using plasma discharge, heat energy or laser, light such as ultraviolet light, decomposed, deposited on a substrate, A method for forming a thin film is known. In addition, when an element other than silicon is added to the material of the thin film to form a compound semiconductor such as a-SiGe: H or a-SiC: H as an amorphous material having a desired optical band gap, a source gas is used. Besides silane (SiH ₄ ), germane (Ge
H ₄ ) or methane (CH ₄ ) is used. When doping the amorphous material with boron or phosphorus, diborane (B ₂ H ₆ ) or phosphine (PH ₃ ) is added to the reaction gas. When a reaction gas obtained by mixing such different types of source gases is used, the source gas is decomposed with energy so that the most difficult to decompose among the source gases can be decomposed. For this reason, a gas having a low decomposition energy cannot be dissociated under optimum conditions, and there is a problem that undesired radicals are generated. In order to solve this problem, as disclosed in Japanese Patent Application No. 2-9799, decomposition energy is given to each raw material gas independently, and each raw material gas is dissociated and decomposed under the most suitable optimum condition, and the substrate gas is decomposed. Research on depositing a thin film to form a thin film has been advanced.

FIG. 7 shows a vapor phase growth apparatus constructed based on Japanese Patent Application No. 2-9799 as an example of this kind of vapor phase growth apparatus. Inside a reaction tank 1 formed as a vacuum vessel and having a carrier gas inlet 11 and a gas exhaust port 12, a substrate heater 2 for keeping the mounted substrate 3 at a predetermined high temperature is arranged. A plurality of compound gases each containing one component in the thin film formed on the surface of the substrate 3, for example, silane (SiH ₄ ), diborane (B ₂ H ₆ ), methane (CH ₄ )
Gas introduction pipes 51, 52, 53 for feeding
Extend from the gas inlets 41, 42, 43 formed in the ceiling plate of the vacuum vessel 4 provided in the upper part of the reaction tank 1 through the ceiling plate of the reaction tank 1 into the reaction tank 1. Each compound gas is blown onto the substrate 3 from the introduction tube. These compound gases are heated and decomposed by the heating resistance wire 71 wound in a coil shape around the quartz pipe 72 through which the gas introduction pipes 51, 52, and 53 are inserted, and radicals generated by the decomposition are converted as reaction products. The thin film is deposited on the substrate 3 to form a thin film. In the drawing, reference numeral 6 denotes a shielding tube for shielding the heat radiation in the radial direction from the heating resistance wire 71 and preventing diffusion of impurities from the heating resistance wire 71 into the reaction tank 1.
Is a temperature sensor for controlling the temperature of each of the gas introduction pipes 51, 52, 53 to a temperature at which each compound gas is dissociated and decomposed at an optimum temperature, and is a wound heater comprising a quartz pipe 72 and a heating resistance wire 71. 7, the shielding cylinder 6, and the temperature sensor 8 constitute a device body side of a gas decomposition heater unit for decomposing a compound gas at an optimum temperature.

[0004]

As described above, when the compound gas is decomposed at the optimum temperature, and it is attempted to reach the substrate while maintaining the decomposition state, the gas heating of the gas decomposition heater unit is performed near the substrate surface. A heater (the winding heater 7 in the above example) is disposed, and the substrate temperature rises due to heat rays such as infrared rays emitted from the gas heater,
Independent control of the substrate temperature by only the substrate heater (2) cannot be performed, and the composition of the thin film deposited on the substrate changes, which is a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to control a substrate temperature independently to a predetermined temperature only by a substrate heater, and to deposit a decomposition product of a compound gas decomposed under an optimum temperature condition on the substrate. An object of the present invention is to provide a configuration of a vapor phase growth apparatus that does not change the composition of a thin film.

[0006]

In order to solve the above problems, the present invention provides a compound containing a thin film component, which is introduced into a reaction tank when a thin film is formed on the surface of a substrate disposed in the reaction tank. A gas phase growth apparatus comprising a gas decomposition heater unit having a gas heater for heating and decomposing gas and a substrate heater for keeping the substrate at a predetermined high temperature is provided. It is assumed that the apparatus is provided with heat shielding means for shielding heat irradiation from the gas heater.

As a specific configuration of a vapor phase growth apparatus based on such a configuration principle, a compound gas is introduced into a reaction vessel through a gas introduction pipe which penetrates a wall surface of the reaction vessel and protrudes into the reaction vessel. The heating unit for gas decomposition is a gas heater, and a heating heater is formed by winding a heating resistance wire in a coil shape around an infrared transmitting pipe through which the gas introduction pipe is inserted as a gas heating heater. A shield tube enclosing in a shape to shield radial heat radiation from the coil heater and preventing diffusion of impurities from the coil heater into the reaction tank; and a temperature sensor for detecting the temperature of the coil heater Wherein the heat shielding means for shielding the substrate from heat irradiation from the gas heater is a plate made of a low thermal conductivity material having a gas inlet through which the gas inlet tube can be inserted. In this case, the compound gas is introduced into the reaction vessel through the gas introduction pipe that penetrates through the wall of the reaction vessel and protrudes into the reaction vessel. In addition, the heating unit for gas decomposition is a heating resistance wire wound in a coil shape in a double cylindrical container in which the gas introduction pipe is inserted as a gas heater and the internal space of which is kept in a reduced pressure state. An infrared heater that seals the infrared heater _, a shielding cylinder that surrounds the infrared heater in a cylindrical shape from the outside to shield radial heat radiation from the infrared heater, and a temperature sensor that detects the temperature of the infrared heater. A heat shielding means for shielding the substrate from heat irradiation from the gas heater, comprising a plate made of a low heat conductive material and having a gas inlet through which the gas inlet tube can be inserted; The device is attached to the end of the gas introduction pipe, or the compound gas is introduced into the reaction vessel through the gas introduction pipe that penetrates the wall of the reaction vessel and protrudes into the reaction vessel. The decomposition heater unit has a built-in heating resistance wire inside a cavity with a mirror surface on the inner wall surface as a gas heater and an opening for drawing out the internal heat to the outside. A hollow heater to be heated, and a heat conducting rod whose inner peripheral surface functions as a total reflection surface for heat, which guides heat going from the opening of the cavity to the outside through the wall surface of the reaction tank to the end face of the gas introduction pipe in the reaction tank. And a temperature sensor for detecting the temperature of the end face of the gas introduction pipe, and it is preferable that the heat guide rod also serves as a heat shielding means for shielding the substrate from heat irradiation from the gas heater.

It is preferable that the heat conducting rod is constituted by a metal pipe having an inner surface plated with gold as a heat conducting path. Further, in the case of an apparatus configuration using a plate made of a low heat conductive material as the heat shielding means, the heat shielding means is formed with a concave surface facing the substrate, and the gas inlet is formed in the concave portion. It is further preferable that the recess is covered with an electrode plate made of a perforated plate or a mesh plate to which a high-frequency voltage is applied.

[0009]

As described above, the apparatus is provided with the heat shielding means for shielding the substrate from heat irradiation from the gas heater between the gas heater and the substrate. Is shielded and the substrate is no longer heated by the gas heater, so that the temperature of the substrate can be controlled solely by the substrate heater alone. Further, since the heat irradiation from the gas heater to the thin film deposited on the substrate is eliminated, a change in the thin film composition due to heating is prevented.

In order to specifically realize the vapor phase growth apparatus configured as described above, the compound gas is introduced into the reaction tank by introducing a gas that penetrates the wall of the reaction tank and protrudes into the reaction tank. Through the pipe, the heater unit for gas decomposition,
A coil heater formed by winding a heating resistance wire around an infrared transmitting pipe through which the gas introduction pipe is inserted as a gas heater; and a radial heat from the coil heater by surrounding the coil heater in a cylindrical shape from the outside. A shielding tube for shielding radiation and preventing diffusion of impurities from the coil heater into the reaction tank;
A gas inlet configured to use a temperature sensor for detecting the temperature of the coil heater and a heat shielding means for shielding the substrate from heat irradiation from the gas heater is formed so that the gas introduction pipe can be inserted therethrough. Further, when formed from a plate made of a material having a low thermal conductivity and attached to the end face of the gas introduction pipe of the coil heater, the plate-shaped heat shielding means can be used without obstructing the outflow of the compound gas toward the substrate. It can be provided in an arbitrary size in the reaction tank, and has a simple structure compared with the case where multiple reflectors are used as a heat shielding means, and can provide heat shielding even in a state where decomposition products of the compound gas are attached. It can be done effectively.

The introduction of the compound gas into the reaction tank is
The reaction is performed through a gas introduction pipe protruding into the reaction vessel through the wall of the reaction vessel, and the heater unit for gas decomposition is used as a gas heater, and a double cylindrical shape through which the gas introduction pipe is inserted. Heater that seals a heating resistance wire wound in a coil in a container that is kept at a constant temperature _, and radially radiates heat from the infrared heater by surrounding the infrared heater in a cylindrical shape from outside. A gas inlet configured to include a shielding cylinder and a temperature sensor for detecting a temperature of the infrared heater, and a heat shielding means for shielding a substrate from heat irradiation from a gas heater; Formed of a plate made of a low thermal conductive material,
When the infrared heater is attached to the end face of the gas introduction pipe, the impurity gas from the gas heater is confined in a small double cylindrical container and does not flow out into the reaction tank.
Impurity gas diffusion can be extremely reliably prevented, and film formation in a state in which the impurity gas is mixed can be reliably prevented. In addition, since the inner space of the double cylindrical container is kept in a reduced pressure state when the heating resistance wire is not energized, the inside of the container is maintained at a relatively low pressure even when the temperature rises during energization or when impurity gas is released. In addition, the container can be formed relatively lightweight without increasing the wall thickness, and the increase in the apparatus cost is small compared to the case where the diffusion of the impurity gas is prevented by the shielding cylinder.

The introduction of the compound gas into the reaction tank is
While performing through the gas introduction pipe that penetrates the wall of the reaction tank and protrudes into the reaction tank, the heater unit for gas decomposition is
A cavity heater having a built-in heating resistance wire inside a cavity in which an inner wall surface is formed as a mirror surface and an opening for drawing out internal heat to the outside as a gas heater, and which is disposed outside the reaction tank; A heat conducting rod having an inner peripheral surface functioning as a total reflection surface of heat, and a heat conducting rod for guiding heat from the opening of the cavity to the outside through the wall surface of the reaction vessel to the end face of the gas introduction pipe in the reaction vessel; When configured using a temperature sensor that detects the temperature and the heat conducting rod also serves as a heat shielding unit that shields the substrate from heat irradiation from the gas heater, heat irradiation from the gas heater to the substrate is prevented. In addition, it is possible to completely prevent impurity gas from being mixed into the reaction tank from the heating resistance wire, and to obtain a thin film having better film quality.

When the heat conducting rod is constituted by a metal pipe having an inner surface plated with gold as a heat conducting path, heat from the hollow heater is transmitted through the air space in the metal pipe. Performance is maintained unchanged.

Further, in the case of an apparatus configuration using a plate made of a low thermal conductivity material and having a gas inlet through which a gas inlet tube can be inserted as the heat shielding means, the plate has a concave surface facing the substrate. If the gas introducing port is formed in the concave portion and the concave portion is covered with an electrode plate made of a perforated plate or a mesh plate to which a high-frequency voltage is applied, the gas introduction into the concave portion is introduced. The dissociated / decomposed gas from the tube flows out from the electrode plate formed of a perforated plate or a mesh plate at a uniform gas density, and a high-frequency voltage is applied to the dissociated / decomposed gas. The dissociation / decomposition gas to which the high-frequency voltage is applied further becomes a plasma state, and the optical band gap of the thin film deposited on the substrate is compared with the case where the gas that does not dissociation / decomposition is directly converted into plasma, as described in detail in the section of Examples. Becomes smaller. Accordingly, by setting the area of the concave portion to a size corresponding to the area of the substrate, a film having better characteristics and a more uniform thickness can be formed on a substrate having a larger area.

[0015]

FIG. 1 shows a first embodiment of the present invention. In the drawing, the same members as those in FIG. 7 are denoted by the same reference numerals.
Gas inlet pipe 5 for introducing compound gas into reaction tank 1
When the heating temperature is, for example, 600 ° C. or more, a metal tube and a heat-resistant porcelain tube are used for 1,52,53, and gas is introduced so that the inside of the reaction tank 1 becomes a heat-resistant porcelain tube. Mouth 4
Attached to 1, 42, 43. External gas introduction pipe 5
The gas heater for thermally decomposing the compound gas sent to 1, 52, 53 is a quartz pipe that transmits infrared rays well.
Winding heater 7 with heating resistance wire 71 wound in a coil shape around 72
And the height of the coil is set so that the gas is decomposed at the optimum temperature and most efficiently under the given gas flow rate and gas type. The shielding cylinder 6 is formed by using heat-resistant porcelain, and effectively shields heat radiated outward from the coil heater 7 in the radial direction even when decomposition products of the compound gas adhere to the inner and outer peripheral surfaces of the cylinder. Thus, the heating power supplied to the winding heater 7 is efficiently consumed for gas decomposition. The gas decomposition heater unit for decomposing the compound gas sent to each of the gas introduction pipes 51, 52, and 53 at an optimum temperature respectively includes the above-described coil heater 7 and
It is composed of a shielding cylinder 6, a temperature sensor 8 for detecting the temperature of the coil heater 7, and a temperature controller (not shown).

The heat from the wire heater 7 to the substrate is blocked.
The gas introduction pipes 51, 5
A gas inlet that can insert 2, 53 was formed.
l_TwoO _ThreeA heat-resistant porcelain plate made of
It is large enough to prevent irradiation,
Gas introduction pipes on the end face of the gas introduction pipe
It is attached while inserted in the mouth.

The contact surfaces of the shielding plate 9 made of heat-resistant porcelain and the shielding cylinder 6 made of the above-mentioned heat-resistant porcelain are each finished to a smooth flat surface by grinding, and are substantially in close contact with each other when assembled as shown in the figure. To minimize the diffusion of the impurity gas from the heating resistance wire 71 into the reaction tank 1.

[0018] With the configuration of this example was measured in the upper surface of the temperature T _a of the substrate heater 2 made by casting the heated resistance wire during ingot aluminum, a time change after the start of energization of the winding heater 7 As a result, as shown in FIG. 2, a high vacuum state (the pressure P
₁ = _1. 33 × 10 ^-4 the temperature T _a in [Pa]), the reactor pressure H ₂ 100% of the gas into the reaction vessel 1 is P ₂ = 13
It was confirmed that the temperature change was extremely small, that is, the maximum temperature change ΔT _a = 5 ° C. even after the flow was supplied at a flow rate of 3 [Pa] and the coil heater 7 was energized.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the gas heater 10 houses an infrared lamp in which a filament for a light source is sealed in a vacuum vessel as a heating resistance wire in a cavity 10b formed by using a metal plate and having an inner wall surface mirror-finished. Formed as a hollow heater,
The same number of gas introduction pipes 51, 52, 53 are arranged outside the reaction tank 1. The gas decomposition heater unit that decomposes each compound gas sent to the gas introduction pipes 51, 52, and 53 at an optimum temperature respectively uses the cavity heater 10 and an opening formed in the cavity 10b to generate heat from the infrared lamp. A heat conducting rod 20, which is guided to the distal end of each of the introduction pipes 51, 52, and 53, is provided with a gold plating on an inner peripheral surface of the metal pipe to form a total reflection surface of infrared rays, and a distal end of which is sealed with a quartz plug. Gas inlet pipe 51, 5
The temperature sensor 8 detects the temperature at the tip. In addition, cooling water is sent from the outside into the housing 10a which forms the cavity 10b of the cavity heater 10 inside, thereby preventing an excessive rise in temperature of the wall surface of the cavity 10b due to heat of the infrared lamp.

When the heater unit for gas decomposition is configured in this manner, since the inner peripheral surface of the heat conducting rod constitutes a total reflection surface of infrared rays, irradiation of infrared rays to the substrate is prevented, and heating of the substrate by the gas heater is prevented. Therefore, the substrate temperature can be easily controlled only by the substrate heater. In addition, impurities due to heating and heating of the heating resistance wire are not mixed into the reaction tank, and a thin film having better film quality can be formed on the substrate.

FIG. 4 shows a third embodiment of the present invention. In the figure, the same members as those in FIG. The gas heater of the gas decomposition heater unit 73 has an internal space kept in a depressurized state. Here, an infrared ray in which a heating resistance wire 71 wound in a coil shape in a double cylindrical container 74 made of quartz is sealed. It is configured as a heater 70, and gas introduction pipes 51, 52, 53 are inserted in the center thereof in the axial direction. A shielding plate for shielding the substrate 9 from heat irradiation from the infrared heater 70
19 is made of heat-resistant porcelain, and the surface facing the substrate 3 is formed concave. This concave portion is covered with an electrode plate 20 composed of a perforated plate or a mesh plate in which fine meshes are uniformly formed, in which a large number of fine pores are uniformly distributed. , A high frequency power supply 15 is connected.

The compound gas fed into the reaction tank 1 through the gas introduction pipes 51, 52, 53 during film formation is supplied to an infrared heater.
Due to 70, they are dissociated and decomposed at their respective optimum temperatures, flow into the recesses of the shielding plate 19, and further pass through the electrode plate 20 and flow out at a uniform gas density. The released dissociated / decomposed gas is
In a high-frequency electric field between the electrode plate 20 and the substrate 3, a plasma state is established, and a thin film is formed on the surface of the substrate 3 heated to a predetermined high temperature by the substrate heater 2.

FIG. 5 shows the optical bandgap value Eg (eV) in the case where the a-Si: H film is formed by converting the previously decomposed compound gas into plasma. Substrate heating temperature T _S
Was maintained at 220 ° C. constant, varying the temperature T _P of the infrared heater 70, the optical band gap value T _P = 300 ° C. or higher is rapidly reduced, the temperature T _P = 500 ° C. Infrared heaters
, A low value of the optical band gap value Eg of 1.68 eV is obtained. In contrast, the conventional high-frequency plasma CV
As and D, without prior thermal decomposition of a compound gas, in the case of direct plasma was formed a-Si: optical band gap values Eg of the H film, as shown in FIG. 6, the substrate temperature T _S
= 220 ° C., infrared heater temperature T _P in FIG.
= 300 ° C. or lower. In order to lower the optical bandgap value Eg below this, the substrate temperature T _S must be set to 220 ° C.
Must be raised above ℃. Conventionally, the substrate temperature T _S has been set high in order to obtain a low optical band gap value Eg. However, in the case of the a-Si: H film, the substrate temperature T _S = 200 ° C. to 25 ° C.
Since a thin film having the best film quality can be obtained at 0 ° C., there is a limit in increasing the substrate temperature T _S , and therefore, there is a limit in decreasing the optical band gap value Eg.

[0024]

According to the present invention, since the vapor phase growth apparatus is configured as described above, the following effects can be obtained.

First, since the heat from the gas heater to the substrate is shielded and the substrate is not heated by the gas heater, the temperature of the substrate can be controlled solely by the substrate heater alone. Temperature control for maintaining a predetermined high temperature becomes easy. At the same time, heat irradiation from the gas heater to the thin film deposited on the substrate is eliminated, so that a change in the thin film composition due to heating is prevented, and a thin film having an intended composition can be reliably obtained.

In the apparatus according to the first aspect, the plate-shaped heat shielding means is provided without obstructing the outflow of the compound gas toward the substrate.
It can be provided in an arbitrary size in the reaction tank, and has a simpler structure than the case where multiple reflectors are used as heat shielding means, and is effective in heat shielding even when decomposition products of compound gas are attached. This effect can be realized at a low cost.

According to the second aspect of the present invention, since the heating resistance wire for thermally decomposing the compound gas is sealed in a depressurized double cylindrical hermetic container, the impurity gas generated from the heating resistance wire is sealed. Is confined in a closed vessel, does not diffuse into the reaction tank, can reliably prevent film formation in a state in which impurity gas is mixed, and can form a thin film having good film quality. Further, since the heating resistance wire does not come into contact with the thermally decomposed compound gas, it is possible to reliably prevent the life from being shortened due to the reaction with the compound gas. And
These effects can be obtained with a slight increase in cost compared to the device configuration of the first aspect.

In the apparatus according to the third aspect, in addition to preventing heat irradiation from the gas heater to the substrate, it is possible to completely prevent impurity gas from being mixed into the reaction tank from the heating resistance wire, thereby improving the film quality. A good thin film can be obtained.

In the apparatus according to the fourth aspect, since heat is transmitted through the air space in the metal pipe, the heat conducting performance and the heat shielding performance of the heat conducting rod are maintained unchanged, and the reliability of the gas decomposition heater unit is maintained at a high level. Has the effect of being done.

In the apparatus according to the fifth aspect, the plate-shaped heat shielding means is formed with a concave surface facing the substrate, a gas inlet is formed in the concave portion, and a high frequency voltage is applied to the concave portion. Since it is covered with an electrode plate made of a perforated plate or a mesh plate, application of a high-frequency voltage to the compound gas is performed after the compound gas is thermally decomposed. For example, when an a-Si: H film is formed, A film having a lower optical band gap value can be formed as compared with a case where a high-frequency voltage is directly applied to H ₂ (carrier gas) + Si ₂ H ₄ (compound gas) which is not thermally decomposed in advance. In addition, since a perforated plate or a mesh plate is used as an electrode plate covering the concave portion of the plate-shaped heat shielding means, by setting the area of the concave portion to a size corresponding to the area of the substrate, a larger area can be obtained. A good film can be formed with a more uniform thickness, and the productivity of the device can be increased.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a vapor phase growth apparatus according to the present invention, and FIG. 1 (b) is a longitudinal sectional view of a main part of the apparatus.
FIG. 2A is a cross-sectional view taken along line AA in FIG.

FIG. 2 is a diagram showing a temperature change showing a temporal change of a substrate heater upper surface temperature in a vapor phase growth apparatus having a configuration shown in FIG. 1 after energization of a gas heater;

FIG. 3 is a longitudinal sectional view of a main part of a vapor phase growth apparatus according to a second embodiment of the present invention.

FIG. 4 shows a third embodiment of the vapor phase growth apparatus according to the present invention, wherein FIG. 4 (b) is a longitudinal sectional view of a main part of the apparatus,
FIG. 2A is a sectional view taken along the line AA in FIG.

FIG. 5 shows the temperature dependence of the optical band gap value of the a-Si: H film formed using the vapor phase growth apparatus having the structure shown in FIG.
Diagram obtained at a constant temperature of ℃

FIG. 6 is a diagram showing the substrate temperature dependence of the optical band gap value of an a-Si: H film formed by applying a high-frequency voltage directly to a compound gas that has not been thermally decomposed in advance to form a plasma.

FIG. 7 shows an example of a vapor phase growth apparatus configuration,
FIG. 2B is a longitudinal sectional view of a main part of the apparatus, and FIG. 2A is a sectional view taken along line BB in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction tank 2 Substrate heater 3 Substrate 6 Shielding tube 7 Winding heater 8 Temperature sensor 9 Shielding plate (Heat shielding means) 15 High frequency power supply 19 Shielding plate (Heat shielding means) 20 Electrode plate 51 Gas introduction pipe 52 Gas introduction pipe 53 Gas introduction pipe 70 Infrared heater 71 Heating resistance wire 72 Quartz pipe (Infrared transmission pipe) 73 Heater unit for gas decomposition 74 Container

Claims (5)

(57) [Claims] 1. A gas decomposition heater unit having a gas heater for heating and decomposing a compound gas containing a thin film component, which is introduced into the reaction tank when a thin film is formed on the surface of a substrate disposed in the reaction tank. And a substrate heater for maintaining the substrate at a predetermined high temperature, wherein a heat shielding means for shielding the substrate from heat irradiation from the gas heater is provided between the gas heater and the substrate. In the vapor phase growth apparatus, the compound gas is introduced into the reaction tank through a gas introduction pipe penetrating through the wall of the reaction tank and protruding into the reaction tank, and the gas decomposition heater unit is used for gas heating. A winding heater formed by winding a heating resistance wire in a coil shape around an infrared transmitting pipe through which the gas introduction pipe is inserted as a heater;
A shield tube for surrounding the coil heater in a cylindrical shape from the outside to shield radial heat radiation from the coil heater and to prevent impurity diffusion from the coil heater into the reaction tank; A temperature sensor for detecting a temperature of the heater,
And a heat shielding means for shielding the substrate from heat irradiation from the gas heater, comprising a plate made of a low thermal conductivity material having a gas introduction port through which the gas introduction pipe can be inserted, A vapor phase growth apparatus attached to a tube end face side. 2. A gas decomposition heater unit having a gas heater for heating and decomposing a compound gas containing a thin film component, which is introduced into the reaction tank when a thin film is formed on the surface of a substrate disposed in the reaction tank. And a substrate heater for maintaining the substrate at a predetermined high temperature, wherein a heat shielding means for shielding the substrate from heat irradiation from the gas heater is provided between the gas heater and the substrate. In the vapor phase growth apparatus, the compound gas is introduced into the reaction tank through a gas introduction pipe penetrating through the wall of the reaction tank and protruding into the reaction tank, and the gas decomposition heater unit is used for gas heating. An infrared heater that seals a heating resistance wire wound in a coil shape in a container having a double cylindrical shape through which the gas inlet tube is inserted and whose internal space is kept in a reduced pressure state; From the outside A shielding tube that surrounds in a cylindrical shape to shield radial heat radiation from the infrared heater and prevents diffusion of impurities from the infrared heater into the reaction tank; and a temperature sensor that detects the temperature of the infrared heater. A heat shielding means for shielding the substrate from heat irradiation from the gas heater, comprising a plate made of a material having a low thermal conductivity and having a gas introduction port through which the gas introduction tube can be inserted; A gas phase growth apparatus attached to the end face of a gas introduction pipe. 3. A gas decomposition heater unit having a gas heater for heating and decomposing a compound gas containing a thin film component, which is introduced into the reaction tank when a thin film is formed on the surface of a substrate disposed in the reaction tank. And a substrate heater for maintaining the substrate at a predetermined high temperature, wherein a heat shielding means for shielding the substrate from heat irradiation from the gas heater is provided between the gas heater and the substrate. In the vapor phase growth apparatus, the compound gas is introduced into the reaction tank through a gas introduction pipe penetrating through the wall of the reaction tank and protruding into the reaction tank, and the gas decomposition heater unit is used for gas heating. A hollow heater having a built-in heating resistance wire inside a cavity in which an inner wall surface is formed as a mirror surface and an opening for drawing out internal heat to the outside, and which is disposed outside the reaction tank; The opening of the A heat conducting rod whose inner peripheral surface functions as a total reflection surface of heat, and a temperature that detects the temperature of the end face of the gas introduction pipe. A gas phase growth apparatus comprising: a sensor; and a heat conducting rod also serving as a heat shielding means for shielding the substrate from heat irradiation from a gas heater. 4. A heat conducting rod according to claim 3, wherein the heat conducting rod whose inner peripheral surface functions as a total reflection surface of heat is formed by applying gold plating to the inner peripheral surface of the metal pipe. A vapor phase growth apparatus characterized by the above-mentioned. 5. The gas-phase growth apparatus according to claim 1, wherein the plate-shaped heat shielding means is formed of a low thermal conductivity material and has a gas inlet through which a gas inlet tube can be inserted. The surface facing the substrate is formed in a concave shape, the gas inlet is formed in the concave portion, and the concave portion is covered with an electrode plate made of a perforated plate or a mesh plate to which a high-frequency voltage is applied. Vapor phase growth equipment.