JP3045854B2 - Semiconductor manufacturing apparatus and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus for growing a compound semiconductor layer in a vacuum chamber, particularly in a vacuum chemical epitaxy (VCE) system, and a method of using the same.

[0002]

2. Description of the Related Art In recent years, demand for compound semiconductors, particularly III-V compounds (for example, GaAs), has been increasing as they have better performance than conventional silicon semiconductors. As a method of manufacturing such a compound semiconductor, in an ultra-high vacuum,
The atoms required for the compound to be epitaxially grown are evaporated from the solid material by a heat gun, and these are colliding with the substrate in the form of a molecular beam, and a film is grown on the substrate by molecular beam epitaxy ([MBE] Molecular Beam). Epitaxy) method, or the vapor of a metal methyl or ethyl compound is sent by a carrier gas such as H ₂ and introduced into a normal or reduced pressure reaction chamber, where it is mixed with a Group V hydrogen compound and then reacted on a heated substrate. Metalorganic CVD to grow crystals
([MOCVD] Metal organic Chemical Vapor Depos
ition) method.

[0003]

However, of the above two methods, the MBE method requires an ultra-high vacuum of the order of 10 ^-11 Torr, has a down time at the time of refilling the raw material, and has a low uniformity. Since a substrate rotating mechanism is necessary for growth, mass production is difficult, and it is difficult to supply the material to meet market demand, and thus it is not suitable for mass production. Therefore, the MOCVD method has attracted attention and is actually used. However, since this method is a process in a laminar flow region, distribution tends to occur in the flow direction, and it is difficult to analyze the flow during scale-up. The disadvantage is that the reaction gas is expensive and the utilization efficiency of the reaction gas is low due to its growth mechanism. In addition, since the use efficiency of the reactive gas is low, a large amount of unreacted gas (toxic gas) is generated. In addition, since the carrier gas is added to the unreacted gas, a large amount of toxic waste gas is generated. It has become a problem.

As described above, the MBE method and the MOCVD method have respective disadvantages, and there is a demand for providing a semiconductor manufacturing apparatus that completely eliminates these disadvantages. For this reason, the present inventors, prior to the present application, the above-mentioned MBE method and MOCVD
We have succeeded in developing a semiconductor manufacturing apparatus that combines the advantages of the law and have already filed a patent application (Japanese Patent Application No. 1-91651).
That is, this semiconductor manufacturing apparatus is made of stainless steel and has a substantially cylindrical shape, and has a structure as shown in FIG.
In the figure, reference numeral 100 denotes vacuum chemical epitaxy (Vacuum C).
a vacuum chamber in a chemical epitaxy system. In the vacuum chamber 100, a heater 105 is disposed above the vacuum chamber 100, and a heat equalizing plate 124 is provided below the heater 105. Below the reaction chamber 102
, The first reaction gas diffusion chamber 103 and the second reaction gas diffusion chamber 104 are provided in a substantially integrated state. The first and second reaction gas diffusion chambers 103 and 104 are
The manifold block 101 has a hollow cylindrical shape. The entire vacuum chamber 100 is evacuated in the direction of arrow C by a turbo-molecular pump (not shown).

The reaction chamber 102 includes a floor plate 106 composed of an upper plate 106 of the manifold block 101, a peripheral side wall 107 erected integrally from the upper surface of the floor plate 106,
It comprises a graphite reactor 108 mounted on a support (not shown) provided on the outer peripheral edge of the floor plate 106. The upper end edge of the peripheral side wall 107 is partially cut out, and the cutout portion is formed in the flow portion 107a. A circular notch hole 111 is formed in the center of the ceiling of the reactor 108, and a tray 112 is placed on a step provided on the periphery of the notch hole 111. The tray 112 has a circular cutout hole 112.
The circular GaAs substrate 113 is removably mounted in a state in which a is provided and supported by a step provided on the periphery of the notch hole 112a. A plurality of communication holes 109 are formed at regular intervals in the floor plate 106. The communication holes 109 allow the reaction chamber 102 to communicate with the first reaction gas diffusion chamber 103 therebelow. I have. Reference numeral 110 denotes an exhaust port, which is formed by a gap between the outer peripheral surface of the peripheral side wall 107 and the inner peripheral surface of the reactor 108.

[0006] The first reaction gas diffusion chamber 103 is formed by a hollow plate-shaped manifold block 101 and an inner plate 11.
The upper and lower chambers are divided into two upper and lower chambers at 4, and a middle plate 114 and a peripheral side wall 115 of the manifold block 101 are formed.
And a floor plate 106 of the reaction chamber 102.
In the first reaction gas diffusion chamber 103, a first reaction gas supply pipe 116 for supplying a V group gas (first reaction gas) such as As extends, and its tip is bent downward. An opening is formed at the tip of the downward bent portion. As above
Is arsine (As) by the cracking device 127
H ₃ ) is thermally decomposed into As and H ₂ ,
H ₂ is also introduced into the first reaction gas diffusion chamber 103 along with As. A disc-shaped flange portion 117 is provided on the outer periphery of the opening.
Is formed, so that As or the like discharged from the opening is uniformly diffused in all directions along the flange portion 117. A second reactive gas diffusion chamber 104 is formed below the first reactive gas diffusion chamber 103.

[0007] The second reaction gas diffusion chamber 104 is a middle plate 11 that divides the inside of the manifold block 101 into two upper and lower chambers.
4, the peripheral side wall 115 of the manifold block 101,
And a floor plate 118 of the manifold block 101. From the middle plate 114, a plurality of communication pipes 119 are formed.
Extend toward and correspond to the plurality of communication holes 109 of the first reaction gas diffusion chamber 103. In this case, the gap is set between the communication pipe 119 and the hole wall of the communication hole 109. As a result, the second reaction gas diffusion chamber 104 and the reaction chamber 102 communicate with each other due to the presence of the communication pipe 119, and the communication pipe 119 and the communication hole 109.
The first reactant gas diffusion chamber 103
And the reaction chamber 102 communicate with each other. A recess 120 is formed in the floor plate 118, and the recess 120 has triethyl gallium (TEGa) and triethyl aluminum (TEGa).
Supply pipe 12 for supplying a group III compound gas such as Al) and an n-type dopant (second reaction gas)
One end opening is open. A baffle plate 122 is provided slightly above the opening of the recess 120 so as to face the opening, whereby the second reaction gas is discharged from the supply pipe 121 into the recess 120. The second reaction gas enters the second reaction gas diffusion chamber 104 while uniformly diffusing in all directions along the baffle plate 122. Reference numeral 123 denotes a cooling water passage, which is disposed in contact with the lower surface of the floor plate 118 and
The inside of the second reaction gas diffusion chamber 104 is cooled by the cooling water passing therethrough.

In this semiconductor manufacturing apparatus, the MESFE
The growth and formation of the T epitaxy layer are performed as follows. That is, the substrate 113 (the surface of which faces downward) is mounted in the reaction chamber 102, then the inside of the vacuum chamber 100 is set in a high vacuum state, and then the heater 105 is energized to generate heat. The substrate 1 via
13 is uniformly heated to a high temperature (about 700 ° C.) to remove impurities from the substrate 113 and to clean the substrate 113. Next,
The substrate temperature is lowered (about 600 to 650 ° C.), and As or the like is supplied from the first reaction gas supply pipe 116 to the first reaction gas diffusion chamber 10.
3 into a uniform mixing state inside the communication hole 109.
And into the reaction chamber 102. At this time, the second
The TEGa, TEAl, and the like are sent from the reaction gas supply pipe 121 into the second reaction gas diffusion chamber 104 to be uniformly diffused, and are discharged into the reaction chamber 102 through the communication pipe 119 in that state. These are brought into contact with the substrate surface together with As ₂ and undoped aluminum gallium arsenide (AlGa).
As) Grow as a film. Finally, the n-type dopant is supplied to the reaction chamber 10 through the same route as TEGa, TEAl, etc.
2 and an n-type active layer is grown on the surface of the undoped AlGaAs film. Unconsumed compounds that do not come into contact with the substrate surface are discharged to the outside through the exhaust port 110 and are exhausted by the exhaust means. Thereafter, the gas supply is stopped for a predetermined period of time, and the substrate 113 is cooled and then taken out of the reaction chamber 102. In this way, a semiconductor having a uniform MESFET semiconductor layer can be obtained.

However, in the above-mentioned semiconductor manufacturing apparatus,
Heat during the AlGaAs film forming process on the substrate surface is the second
And the inner wall temperature of the diffusion chamber 104 increases. In this case, although a cooling water passage 123 is provided in the lower part of the second reaction gas diffusion chamber 104, the cooling water passage 123 sufficiently cools the second reaction gas diffusion chamber 104. Therefore, the temperature in the second reaction gas diffusion chamber 104 is considerably high (about 210 ° C.). However, while TEGa sent into the second reaction gas diffusion chamber 104 has a decomposition temperature of 450 ° C., TEAl has a low decomposition temperature (150 to 200 ° C.). Therefore, most of TEAl is decomposed in the second reaction gas diffusion chamber 104 and
02 was not reached in the TEAl state. Further, T decomposed into the reaction chamber 102 without being decomposed.
EAl is also decomposed in the process of passing through the communication pipe 119, and the reaction chamber 1
02, reacts with other reaction gas as soon as it enters the communication pipe 11.
An AlGaAs film is formed on the reaction chamber 102 near the exit 9. Therefore, Al generated on the substrate surface
Since the GaAs film contains only a predetermined amount or less of Al, there is a problem that a defective product is formed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a semiconductor manufacturing apparatus which does not reduce the amount of Al contained in an AlGaAs film on a substrate surface and a method of using the same.

[0011]

In order to achieve the above object, the present invention provides a vacuum chamber, a reaction chamber provided in the vacuum chamber, and a substrate which can be held with the substrate surface in contact with the reaction space. A substrate holding portion provided on a ceiling portion of the reaction chamber, a heating element provided above the substrate so as to heat the substrate, and communicating with a bottom surface of the reaction chamber provided below the reaction chamber. First and second reaction gas diffusion chambers each having a gas outlet group to be formed, a first reaction gas supply pipe having its own tip opening opening into the first reaction gas diffusion chamber, and itself. A semiconductor manufacturing apparatus comprising a second reaction gas supply pipe having a front end opening opening into the second reaction gas diffusion chamber, wherein the second reaction gas diffusion pipe is provided substantially at the center of the bottom surface of the reaction chamber. While arranging a room, The first reactant gas diffusion chamber is disposed in a peripheral portion of the first reactant gas diffusion chamber, and the periphery of the gas outlet group of the second reactant gas diffusion chamber formed on the bottom surface of the reactant chamber is defined by the first reactant gas diffusion chamber. A semiconductor manufacturing apparatus which is surrounded by a group of gas outlets, has a cooling chamber provided below the second reaction gas diffusion chamber, and allows the second reaction gas supply pipe to pass through the cooling chamber. 1. A method of manufacturing a semiconductor in which a semiconductor layer is grown on a surface of a substrate by using the semiconductor manufacturing apparatus, wherein the vacuum chamber is in a high vacuum state and the surface of the substrate is on the lower side. When the substrate is heated and preheated by the heat generated by a heating element disposed above the substrate holding unit, the opening is opened to the first reaction gas diffusion chamber. First reaction of As etc. from the plurality of first gas outlets into the reaction chamber Blowing a small amount of scan at the same time, the use of a semiconductor manufacturing apparatus that blows a small amount of Kiyariagasu such as H ₂ from a plurality of second gas outlet which opens into the second reaction gas diffusion chamber to the reaction chamber of the second Make a summary.

[0012]

According to the semiconductor manufacturing apparatus of the present invention, the second reaction gas diffusion chamber is disposed substantially at the center of the bottom surface of the reaction chamber, and the first reaction gas diffusion chamber is disposed at the periphery surrounding the substantially center. A cooling chamber is provided below the second reaction gas diffusion chamber, and the second reaction gas supply pipe is caused to pass through the cooling chamber. While being efficiently cooled, TEAl or the like supplied to the second reaction gas diffusion chamber is directly sent to the reaction chamber. Therefore, TEAl reaches the substrate surface as it is,
Therefore, the substrate is thermally decomposed only by the heat of the substrate, and reacts with another reaction gas. As a result, Al formed on the substrate surface
The GaAs film contains Al as calculated. Also, according to the method of use of the present invention, after preheating the substrate,
At the start of the reaction for forming an AlGaAs film on the substrate surface, useless reaction between TEAl or the like and As or the like can be prevented. That is, when the substrate is preheated, the temperature of the substrate becomes high, which causes a phenomenon that As jumps out of the substrate. In order to prevent this, As gas is supplied to the reaction chamber via the first reaction gas diffusion chamber. At this stage, the second reaction gas diffusion chamber has no pressure (at this stage, the reaction gas is supplied). Is not done). Accordingly, the As supplied to the reaction chamber enters the second reaction gas diffusion chamber, and in that state, TEA is subsequently supplied to the second reaction gas diffusion chamber.
When 1 or the like is supplied, rarely, an AlGaAs generation reaction occurs in the second reaction gas diffusion chamber. Therefore, in the method of use of the present invention, a carrier gas such as H ₂ is fed into the second reaction gas diffusion chamber during the preheating of the substrate,
As and the like are prevented from entering the second reaction gas diffusion chamber.

Next, the present invention will be described in detail based on embodiments.

[0014]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a main part thereof. In these figures, reference numeral 1 denotes a vacuum chamber made of stainless steel in a vacuum chemical epitaxy system, and a reaction chamber 2 is formed in the vacuum chamber 1. The reaction chamber 2 includes a cup-shaped reactor 3 made of carbon graphite and an upper plate 4a of a manifold block 4, and a space surrounded by the reactor 3 and the upper plate 4a is a reaction space. The reactor 3 has a round hole 3a in the ceiling thereof.
The tray 50 is placed on a step formed on the periphery of the round hole 3a. Then, a circular cutout hole is formed in the tray 50, and the circular GaAs substrate 13 is removably mounted on a substrate holding portion 39 formed in a stepped shape at the periphery of the cutout hole. The inner wall surface of the reactor 3 is coated with silicon carbide, and in contrast to the fact that the reactor 3 is made of carbon graphite, AlGaAs is used.
When the film is formed, the inner wall surface of the reactor 3 becomes hot water. As a result, even if gas molecules such as As collide with the wall surface, the molecular particles crystallize on the wall surface and are repelled without being attached,
Eventually, it becomes involved in the reaction of AlGaAs formed on the substrate surface. Accordingly, the use efficiency of the source gas is improved. The manifold block 4 comprises a substantially hollow cylindrical second reaction gas diffusion chamber 22 and a substantially donut-shaped first reaction gas diffusion chamber 21 surrounding the second reaction gas diffusion chamber 21. This configuration is one of the features of the present invention.

The first doughnut-shaped first reaction gas diffusion chamber 21 comprises a lower annular block 7, an upper annular block 6, and a partition plate 17 separating the blocks 6 and 7. The lower annular block 7 constitutes a lower diffusion chamber 23, and as shown in FIG. 2, a bottom wall portion 8 of an annular flat plate and an inner vertical wall portion standing upright from an inner peripheral edge of the bottom wall portion 8. 9, an outer vertical wall portion 10 erected from the outer peripheral edge of the bottom wall portion 8, and a projecting portion 1 formed on the outer peripheral surface of the outer vertical wall portion 10 so as to protrude laterally.
1 is provided. The overhang portion 11 has an exhaust port 12 formed in a circumferential direction. The lower end of the outer vertical wall portion 10 is removably fitted into a groove 5a formed on the outer peripheral edge of the bottom plate 5 for supporting the manifold block 4, whereby the manifold block 4 and the reaction chamber 4a together with the bottom plate 5 are attached. It can be removed from. A ridge 11a is formed upward on the outer peripheral edge of the lateral wall portion 11, and a groove 3c formed at the lower end of the reactor 3 is detachably fitted to the ridge 11a. In addition, both the vertical wall portions 9 and 1
In FIG. 0, ridges 9a, 10a are formed on the peripheral surface, and an annular partition plate 17 is detachably mounted on the ridges 9a, 10a. The partition plate 17 is curved in an upward arch shape and has a large number of holes 20a. The upper annular block 6 constitutes an upper diffusion chamber 24. The upper annular block 6 includes an inner vertical wall portion 14, an outer vertical wall portion 15, and a porous horizontal wall portion 16 formed of the outer peripheral side of the upper plate 4a of the manifold block 4. Have. The upper annular block 6 is provided with the two vertical wall portions 1.
The protrusions 14a, 15a formed at the lower ends of the lower annular block 7 are fitted into the grooves 9b, 10b formed at the upper ends of both the vertical wall portions 9, 10 of the lower annular block 7, thereby forming the lower annular block 7. In contrast, it is detachable. It should be noted that the outer peripheral side portion of the perforated horizontal wall portion 16 is bent upward so as to face the substrate 13, and a number of gas outlets 16 a formed in the perforated horizontal wall portion 16 are formed toward the substrate 13. It is that you are. As a result, the distance between each gas outlet 16a and the substrate 13 becomes substantially equal, and the reaction gas blown out from each gas outlet 16a comes into uniform contact with the substrate 13 per unit area. At the upper end of the outer vertical wall portion 15, a vertical exhaust ring 48 for adjusting a gap A between the upper end of the outer vertical wall portion 15 and the ceiling of the reactor 3 is provided.
5b and the groove 48a are fitted so as to be detachable (by removing, the gap A is widened). In the first reaction gas diffusion chamber 21 configured as described above,
As gas (first reaction gas) generated via a cracker (not shown) is blown out and supplied to the lower annular block 7 from the tip opening 40 c of the first reaction gas supply pipe 40. More specifically, in FIG. 1, the first reactant gas supply pipe 40 extends from a cracker (located on the back side of the drawing and hidden behind the distributor 44).
The ends of both branch pipes 40 a pass through the bottom plate 5 and the bottom wall 8 of the first reaction gas diffusion chamber 21 and open into the lower diffusion chamber 23. FIG. 3 is a plan view showing the relationship among the first reaction gas supply pipe 40, the cracker 49, and the distributor 44. FIG. 1 shows these 40, 49, and 44 viewed from the arrow direction. As shown in FIG. 4, a root portion of the forked pipe 40b is removably inserted into the opening of the branch pipe 40a, and the forked portion of the forked pipe 40b shows the inside of the lower diffusion chamber 24. It extends like the chain line of 4,
A gas discharge port 40c is formed downward at the tip of the extension (see FIG. 5).

The above-mentioned donut-shaped first reaction gas diffusion chamber 2
In the center of the first donut, a second reaction gas diffusion chamber 22 is provided.
Are positioned and formed. The second reaction gas diffusion chamber 22 includes:
A cylindrical lower block 25 having a concave portion 27 on the upper surface and having a hollow portion 36 therein, a partition plate 30 mounted on the concave portion 27 of the lower block 25, and a cylinder provided on the outer periphery of the upper surface of the lower block 25 The upper block 26 has a cylindrical shape and a perforated horizontal plate 29 covering the upper opening of the cylindrical upper block 26. The lower block 25 is provided in a space between the first reaction gas diffusion chamber 21 and the space (a vacuum space when the apparatus is driven) for the purpose of shutting off heat transfer from the first reaction gas diffusion chamber 21.
The upper block 26 that is in contact with the first reaction gas diffusion chamber 21 is made of a heat-resistant heat insulating material. This is also one of the features of the present invention. A large number of holes 30a are formed in a vertical direction in the partition plate 30 which is capped in the concave portions 27 of the lower block 25, and the perforated horizontal plate portion 29 covering the upper opening of the upper block 26 is curved in a dish shape. The gas outlets 29a (formed by porous holes) formed therein are formed obliquely so that the one located at the center is vertical and the outer one is more outward. As a result, the distance between each gas outlet 29a and the substrate 13 becomes substantially equal, and the reaction gas blown out from each gas outlet 29a comes into uniform contact with the substrate 13 per unit area. This is one of the inventions. The second reactant gas supply pipe 41 extends upward through the center of the hollow portion 36 of the cylindrical lower block 25, and its tip opening is opened at the center of the concave portion 27 of the lower block 25. A cylinder 33 is provided on the outer periphery of the second reaction gas supply pipe 41 with a space therebetween, and the upper end of the cylinder 33 communicates with the cavity 42 of the lower block 25, and the lower end thereof supplies the second reaction gas. It is sealed in a tube 41. The cooling chamber 36 is formed by the cylindrical body 33 and the hollow portion 42 of the lower block 25. 37 is a cooling water supply pipe, and 38 is its discharge pipe. Thereby, the second reaction gas [for example, triethylgallium (TEGa) and triethylaluminum (T
Mixed gas composed of EAl) and hydrogen as a carrier gas is cooled by water in the cooling chamber 36 to such an extent that the mixed gas is not preliminarily decomposed, and TEAl is supplied to the reaction chamber 2 without being thermally decomposed. This is also one of the features of the present invention.

Reference numeral 46 denotes a column extending upward from the bottom plate 47 of the vacuum chamber 1 and supports the bottom plate 5. The other parts are the same as those in FIG. 9 and the same parts are denoted by the same reference numerals.

In the above-mentioned structure, a substrate 13 (having a surface facing downward) is mounted on the reaction chamber 2 as shown in FIG. 1, and then the inside of the vacuum chamber 1 is formed into a high vacuum chamber for growing the MESFET epitaxy layer. And the heater 10
5, the substrate 13 is uniformly heated (preheated) by the heat equalizing plate 124 to purify the substrate 13. That is, at a substrate temperature of about 500 ° C., As
A small amount of gas (eg, a mixed gas of AsH ₃ + H ₂ (50% + 50%) produced by passing through a cracking device to thermally decompose AsH ₃ therein) and the lower diffusion chamber 24 of the first reaction gas diffusion chamber 21 The gas is fed into the upper diffusion chamber 23 through a gas outlet 17 a formed in the partition plate 17 at a rate of 10 to 15 cc / min. In this process, As gas is mixed and the concentration thereof is made uniform. The introduction of a small amount of As gas is for the purpose of supplementing As which jumps out of the substrate 13. Then, while introducing a small amount of As gas, the substrate temperature is raised to about 700 ° C. to purify the substrate 13. At this stage, since the second reactive gas diffusion chamber 22 is not supplied with the reactive gas, the As gas enters here. Since the invading As gas also contains heat, the upper side of the second reaction gas diffusion chamber 22 may be heated and heated. As a result, the second reaction gas cooled by the action of the cooling chamber 36 is thermally decomposed, and this reacts with the As gas to form the second reaction gas.
The upper side of the reaction gas diffusion chamber 22 is, for example, AlGaAs
It is conceivable to form a film. In order to avoid this, the present invention keeps blowing a carrier gas such as hydrogen from the second reaction gas supply pipe 41 while heating the substrate 13 to purify the substrate 13 so that the second reaction gas diffusion chamber 22 can be cooled.
s Prevents gas from entering. This is a feature of the method of use of the present invention. After the substrate 13 is thus purified, the substrate temperature is lowered (about 600 to 650 ° C.).
3 is epitaxially grown on the surface of the semiconductor film. That is, the supply amount of As gas (first reaction gas) from the first reaction gas supply pipe 40 is increased, and, for example, vaporized triethylgallium (TEGa) is supplied to the second reaction gas supply pipe 41. , Vaporized triethylaluminum (TEAl) and H ₂ as carrier gas
The gas is supplied at a predetermined ratio (usually 1: 1) to form a second reaction gas. FIG. 6 shows the relationship between the supply amount of H ₂ during the preheating purification of the substrate 13 and the supply amount of the reaction gas during the subsequent formation of the semiconductor film. The first and second reaction gases supplied in this manner are sufficiently stirred and mixed in the two reaction gas diffusion chambers 21 and 22 to be in a uniform state and are blown into the reaction chamber 2 from the respective gas outlets 16a and 29a. . At this time, as shown in FIG. 1, each gas is blown out while expanding in a circular cross section from the gas outlets 16a and 29a, and strikes the substrate 13 while maintaining the circular cross section. FIG. 7 shows the contact surface when the As gas blown out from each gas outlet 16a hits the surface of the substrate 13 by a circle A. The second reaction gas is sprayed on the overlapping portion B of the circle A. This eliminates the adverse effects of fluctuations in the supply pressure of each reaction gas, and grows an undoped aluminum gallium arsenide (AlGaAs) film uniformly on the surface of the substrate 13. The exhaust gas is exhausted to the outside through the exhaust port 12 and is exhausted by the exhaust means. In this case, the exhaust port 1
2 is formed in a belt shape along the outer peripheral edge of the reaction chamber 2, so that the unconsumed gas is uniformly discharged from the entire circumference, which also contributes to the uniform distribution of the reaction gas in the reaction chamber 2. doing. Next, for example, an n-type dopant is
The n-type active layer is grown on the surface of the undoped AlGaAs layer by discharging the reaction chamber 2 through the same path as EGa + TEAl + H ₂ . Thereafter, the gas supply is kept stopped for a predetermined time, and the substrate 13 is cooled and taken out of the reaction chamber 2. In this way,
A semiconductor having a uniform MESFET semiconductor layer can be obtained. In using the apparatus of the above embodiment, a carrier gas such as hydrogen is supplied to the second reaction gas diffusion chamber 22 when the substrate 13 is purified and preheated, but this is not always necessary. Before the main growth, both the first and second reaction gas diffusion chambers 21 and 22 may be evacuated to 5 × 10 ⁻⁵ Torr.

FIG. 8 shows a main part of another embodiment of the present invention. In this embodiment, the shapes and the like of the first and second reaction gas diffusion chambers are changed as shown. The other parts are substantially the same as those of the above-described embodiment, and the same parts are denoted by the same reference numerals and the description thereof will not be repeated. This embodiment also has the same operation and effect as the above embodiment.

[0020]

As described above, in the semiconductor manufacturing apparatus according to the present invention, the second reaction gas diffusion chamber is disposed substantially at the center of the bottom surface of the reaction chamber, and the second reaction gas diffusion chamber is disposed at the periphery surrounding the substantially center. 1
And a cooling chamber is provided below the second reaction gas diffusion chamber, and the second reaction gas supply pipe is made to pass through the cooling chamber. The gas diffusion chamber is efficiently cooled, and TEAl or the like supplied to the second reaction gas diffusion chamber is directly sent to the reaction chamber. Therefore, TEAl directly reaches the substrate surface without being pre-decomposed, where it is thermally decomposed only by the heat of the substrate and reacts with another reaction gas. As a result, the AlGaAs film formed on the substrate surface contains Al as calculated. Further, according to the method of use of the present invention, after preheating of the substrate, Al
At the start of the reaction for forming a GaAs film, TEAl
It is possible to prevent useless reaction between As, etc. and As, etc. That is, when the substrate is preheated, the temperature of the substrate becomes high, which causes a phenomenon that As jumps out of the substrate. In order to prevent this, As gas is supplied to the reaction chamber via the first reaction gas diffusion chamber. At this stage, the second reaction gas diffusion chamber has no pressure (at this stage, the reaction gas is supplied). Is not done). Therefore, when As previously supplied to the reaction chamber enters the second reaction gas diffusion chamber and TEAl or the like is subsequently supplied to the second reaction gas diffusion chamber in that state, the second reaction gas diffusion chamber is rarely used. AlGaAs in the reaction gas diffusion chamber
Is generated. For this reason, in the usage method of the present application,
At the time of preheating the substrate, a carrier gas such as H ₂ is fed into the second reaction gas diffusion chamber to prevent As and the like from entering the second reaction gas diffusion chamber at the time of preheating the substrate.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductor manufacturing apparatus according to one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the semiconductor manufacturing apparatus.

FIG. 3 is an explanatory view showing the semiconductor manufacturing apparatus as viewed from below.

FIG. 4 is a perspective view of a distal end portion of a first reaction gas supply pipe.

FIG. 5 is a cross-sectional view of a tip opening of a first reaction gas supply pipe.

FIG. 6 is a diagram illustrating a change in the supply amount of a reaction gas and the like during preheating of a substrate and subsequent formation of a semiconductor film.

FIG. 7 is an explanatory diagram showing a state where gas is applied to a substrate.

FIG. 8 is an enlarged sectional view showing a main part of another embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an open state of a distal end opening of a first reaction gas supply pipe.

FIG. 10 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 vacuum tube 2 reaction chamber 13 substrate 16a, 29a gas outlet 21 first reaction gas diffusion chamber 22 second reaction gas diffusion chamber 36 cooling chamber 39 substrate holder 40 first reaction gas supply pipe 41 second reaction gas Supply pipe 43 Heater

Continuation of the front page (72) Inventor Hidehiko Oku 5-743, Uenoshiba Mukaigaoka-cho, Sakai City, Osaka (56) References JP-A 1-2230227 (JP, A) JP-A 2-268419 (JP, A) JP Hei 3-255620 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 H01L 21/365

Claims (5)

(57) [Claims] 1. A vacuum chamber, a reaction chamber provided in the vacuum chamber, and a substrate holding part provided on a ceiling of the reaction chamber so as to hold a substrate with a substrate surface in contact with the reaction space, A heating element provided above the substrate so as to heat the substrate, and a first and a second gas supply port group formed below the reaction chamber and formed with a gas outlet group communicating with a bottom surface of the reaction chamber. A reaction gas diffusion chamber, a first reaction gas supply pipe having its own tip opening opening into the first reaction gas diffusion chamber, and a first reaction gas supply pipe having its own tip opening opening into the second reaction gas diffusion chamber. A semiconductor manufacturing apparatus provided with a second reactant gas supply pipe, wherein the second reactant gas diffusion chamber is disposed substantially at the center of the bottom surface of the reaction chamber, and at the peripheral portion surrounding the substantially center. Providing the first reaction gas diffusion chamber, A group of gas outlets of the second reaction gas diffusion chamber formed on the bottom surface of the reaction chamber is surrounded by a group of gas outlets of the first reaction gas diffusion chamber, and the second reaction gas diffusion chamber is formed. Wherein a cooling chamber is provided under the cooling chamber, and the second reaction gas supply pipe passes through the cooling chamber. 2. The semiconductor manufacturing apparatus according to claim 1, wherein a space for heat insulation is provided between the first reaction gas diffusion chamber and the second reaction gas diffusion chamber. 3. The first and second reaction gas diffusion chambers are respectively formed into two upper and lower chambers by a porous partition wall, and the first reaction gas diffusion chamber is formed in a lower chamber among the two upper and lower chambers. 2. The gas supply pipe according to claim 1, wherein the gas supply pipe has an opening at the end thereof, and the reaction gas blown out from the opening at the end is guided to the upper chamber through the porosity of the partition wall dividing the upper and lower chambers.
The semiconductor manufacturing apparatus according to the above. 4. The semiconductor manufacturing apparatus according to claim 1, wherein the reaction chamber is formed in a cylindrical shape with a bottom, and the bottom surface is formed in a substantially hemispherical shape, and the degree of depression in a substantially central portion of the bottom surface is formed strongly. . 5. A method for manufacturing a semiconductor, comprising: growing a semiconductor layer on a surface of a substrate by using the semiconductor manufacturing apparatus according to claim 1; The first reaction gas is attached to a substrate holding portion provided on the ceiling portion of the reaction chamber in a state where the substrate is heated, and the substrate is heated and preheated by the heat generated by a heater disposed above the substrate holding portion. A small amount of a first reaction gas such as As is blown into the reaction chamber from the plurality of first gas outlets opened to the diffusion chamber, and at the same time, from the plurality of second gas outlets opened to the second reaction gas diffusion chamber. using semiconductor manufacturing apparatus is characterized in that so as to blow out a small amount of Kiyariagasu such as H ₂ into the reaction chamber.