JPH06216033A - Chemical vapor growth device for semiconductor - Google Patents

Abstract

PURPOSE:To provide a semiconductor chemical vapor growth device which is able to form an excellent multilayered thin film high in productivity. CONSTITUTION:A baffle plate 20 where through-holes 23 are bored is provided inside a vertical cylindrical reaction pipe 12 so as to divide a space inside the reaction pipe 12 into two sub-spaces, an upper sub-space 21 on a material gas feed nozzle 17 side and a lower sub-space 22 on the side of a suscepter 14 where a GaAs wafer 15 is placed. By this setup, even if the suscepter 14 is enlarged in area so as to enhance a vapor growth device of this design in throughput without increasing the device in height, material gas fed through the feed nozzles 17 and 17 is rectified in flow as it passes through the through- holes 23 provided to the baffle plate 20 to flow uniformly over the upper surfaces of a large number of the GaAs wafers 15 placed on the suscepter 14, and as the feed nozzles 17 are not distant from the suscepter 14, material gas can be quickly switched in a short time, so that the device can be improved in productivity, and an excellent multilayered thin film can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chemical vapor deposition apparatus, and is particularly suitable for a metal organic chemical vapor deposition method for producing a compound semiconductor substrate.

[0002]

As is well known, gallium arsenide (GaAs)
By a metalorganic chemical vapor deposition method (MOCVD method) in which a metalorganic compound is vapor-phase epitaxially grown on the surface of a GaAs wafer formed by the semi-insulating crystal of
A compound semiconductor substrate is prepared by laminating thin films such as aAs and InGaAlP. The lamination of the thin film on the surface of the GaAs wafer is performed by switching the source gas by a metal organic chemical vapor deposition apparatus (MOCVD apparatus).

Hereinafter, a conventional MOCVD apparatus is shown in FIG.
It will be described with reference to FIGS. FIG. 6 is a vertical cross-sectional view showing the outline of the configuration, FIG. 7 is a plan view showing a mounting state of a GaAs wafer on a susceptor, and FIG. 8 is a vertical cross-sectional view showing a state where a GaAs wafer is heated. FIG. 9 is a temperature distribution diagram of the susceptor.

In FIGS. 6 to 8, 1 is a MOCVD apparatus, which has a height of about 5 which expands downward.
The reaction tube 2 has a substantially conical vertical shape of 50 to 600 mm, and a lower case 3 which is hermetically attached to the lower portion of the reaction tube 2 is provided. The lower case 3 has three GaAs wafers with a diameter of 2 inches.
A susceptor 5 that can place the wafer 4 at a predetermined position and is configured to be rotatable is provided, and a supply nozzle 6 that horizontally discharges the raw material gas is provided above the reaction tube 2 so as to open in the reaction tube 2. Is attached to. The raw material gas is supplied from a raw material gas supply source (not shown) to the reaction tube 2 through a supply nozzle 6 and a pipe in which a valve is inserted, and exhaust gas is discharged from a gas exhaust port 7 formed in the lower case 3. Is discharged.

The susceptor 5 is rotationally driven by a driving device (not shown) and heats the mounted GaAs wafer 4 by a heater 8 incorporated therein. A thermocouple 9 is provided adjacent to the heater 8 and the measured temperature of the thermocouple 9 is input to the control unit 10. The measured temperature becomes the control temperature preset in the control unit 10. Thus, the energization of the heater 8 is controlled by the controller 10. The MOCVD apparatus 1 has
Further, as not shown, a clean bench provided above the reaction tube 2 and a driving device and a control device for moving the reaction tube 2 up and down are provided.

In order to deposit a thin film on the surface of the GaAs wafer 4, first, the reaction tube 2 is lifted, the GaAs wafer 4 is placed at a predetermined position on the susceptor 5, and the inside of the reaction tube 2 is sealed again. The GaAs wafer 4 placed on the susceptor 5 in a depressurized state inside the reaction tube 2 is heated while the heater 8 is controlled to a predetermined temperature by the control unit 10, and the reaction tube 2 is fed through the supply nozzle 6. It is carried out by introducing a raw material gas into the inside. The source gas is switched according to the type of thin film to be laminated by operating a valve inserted in the pipe.

However, in the above-mentioned prior art, the diameter of the susceptor 5 is increased so as to cope with the increase in the production amount, and the number of GaAs wafers 4 that can be mounted is increased, so that a large number of GaAs wafers 4 can be coated with a thin film at a time. When stacking, the entire MOCVD apparatus 1 including the clean bench and the like has a height of about 2 m, and the reaction tube 2 has a substantially conical shape.
As the height of the building becomes higher due to the need to increase the diameter of the lower part, it becomes higher and the existing building cannot be used. That is, for example, if the number of GaAs wafers 4 mounted on the susceptor 5 is increased to 7,
The overall height of the MOCVD apparatus 1 is about 3 to 4 m.

Further, as the height of the substantially conical reaction tube 2 increases, the distance between the supply nozzle 6 and the susceptor 5 increases, and the source gas is switched when a plurality of thin films are sequentially laminated. However, the source gas switching speed in the vicinity of the susceptor 5 becomes slow, and an impure thin film is formed at the interface of the formed predetermined thin film. Therefore, when a semiconductor element is formed from the compound semiconductor substrate formed by this, the characteristics of the semiconductor element are not good and the manufacturing yield is low. Further, the amount of raw material gas required for laminating a predetermined thin film on the GaAs wafer 4 is also large.

On the other hand, in the process of continuously laminating a plurality of thin films on the GaAs wafer 4 by heating, the GaAs wafer 4 is warped as shown in FIG. As a result, a temperature distribution is generated between the susceptor 5 and the GaAs wafer 4 at the central portion of the contact portion and the outer peripheral portion of the non-contact portion. Further, the warp is further increased and the variation in the growth of the thin film is increased. Therefore, the characteristics of the element formed by the GaAs wafer 4 cannot be said to be good, and the yield is low.

Further, the warp of the GaAs wafer 4 causes the seating on the susceptor 5 to deteriorate, and the susceptor 5 rotates to be fitted into a predetermined position such as a mounting recess formed on the upper surface of the susceptor 5, for example. The GaAs wafer 4 that has been used may be detached and scattered in the reaction tube 2 and the lower case 3, which makes the GaAs wafer 4, which is more expensive than the Si wafer, defective and causes a large loss.

Further, since the source gas flows around the susceptor 5 which is heated by the heater 8 while being controlled by the controller 10, as shown in FIG. The peripheral part is deprived of heat and the temperature is low, and the temperature distribution is not uniform. Therefore, the temperature distribution of the GaAs wafer 4 mounted on the susceptor 5 is not uniform, the yield is not increased, and the number of chips taken from the GaAs wafer 4 cannot be increased.

Further, since the temperature of the susceptor 5 is measured by the embedded thermocouple 9 near the heater 8 and controlled by the control unit 10, the temperature of the GaAs wafer 4 is the optimum temperature for film formation. Whether or not it is several GaA
Since the film formation is performed on the s-wafer 4 and the evaluation is performed, it takes time to set the heating temperature for setting the process conditions of the film formation.

[0013]

As described above, if the size of the susceptor is increased and the number of wafers that can be placed is increased in order to cope with the increase in the production amount, the height of the entire apparatus becomes high and the existing building is Since the distance between the supply nozzle and the susceptor is large, the source gas switching speed becomes slow, and an impure thin film may form at the interface of the formed thin film. Is warped or has a temperature distribution due to the influence of the flowing raw material gas, etc., and the characteristics of the semiconductor device produced thereby are not good, and the manufacturing yield is low. The present invention has been made in view of such a situation, and the object thereof is that the height of the entire device does not increase while improving productivity, and the device can be installed in an existing building or the like. An object of the present invention is to provide a semiconductor chemical vapor deposition apparatus capable of rapidly changing raw material gases, suppressing formation of an impure thin film on a wafer, obtaining a uniform temperature distribution, and forming an excellent predetermined thin film.

[0014]

A semiconductor chemical vapor deposition apparatus of the present invention comprises a vertical cylindrical reaction tube whose upper end is closed, and a reaction tube which is attached to the upper side wall of the reaction tube inside the reaction tube. A supply nozzle for delivering the raw material gas, a straightening plate having a plurality of through holes provided below the attachment part of the supply nozzle and vertically dividing the inside of the reaction tube, and the straightening plate. Is provided on the lower side of the susceptor, and a heating unit for heating a wafer placed on the susceptor, and further, at least two supply nozzles are provided, and The raw material gas is delivered from the supply nozzle in the same direction along the inner peripheral surface of the side wall of the reaction tube. Further, the opening ratio of the straightening plate having the through holes is 5 to 15%. In addition, the heating part is It is characterized in that it comprises a heating heater consisting of a number of heater portions, and that each heater portion is provided so that the calorific value can be adjusted individually. In the semiconductor chemical vapor deposition apparatus, which is provided with a susceptor on which a wafer is placed, and which is provided with a heating unit for heating the susceptor from the lower side, so that a predetermined film is grown on the upper surface of the wafer,
A temperature measuring unit for measuring the temperature near the upper part of the wafer placed on the upper surface of the susceptor is provided while scanning, and the heating unit is equipped with a heating heater composed of a plurality of heater parts. It is characterized in that the heat generation amount of each heater portion is adjusted based on the above, and further, the susceptor has a gap between the susceptor and the lower surface of the mounted wafer. It is a thing.

[0015]

In the semiconductor chemical vapor deposition apparatus constructed as described above, a vertical cylindrical reaction tube is divided into a plurality of penetrating holes, which are divided into a source gas supply nozzle side and a wafer susceptor side. Even if the size of the susceptor is increased so as to increase the number of wafers to be processed at a time without increasing the height of the equipment, the supply nozzle is provided by providing the straightening plate with holes. The raw material gas supplied from is rectified by passing through the through holes of the rectifying plate, and evenly flows on the upper surfaces of many wafers mounted on the susceptor, so that a uniform thin film can be formed. Further, since the distance between the supply nozzle and the susceptor does not become long, the source gas can be switched within a short time. Therefore, the height of the entire apparatus is not increased while productivity is improved, and the formation of an impure thin film can be suppressed by rapid switching of the source gas, and a good thin film can be formed.

Further, the semiconductor chemical vapor deposition apparatus configured as described above is provided with a temperature measuring unit for measuring the temperature near the upper part of the wafer placed on the upper surface of the susceptor while scanning, and heating The heater is composed of a plurality of heater parts, and the heat generation amount of each heater part is adjusted based on the temperature measured by the temperature measurement part. As a result, the temperature near the upper part of the wafer is divided into a plurality of parts. A desired temperature distribution, for example, the temperature in the upper vicinity of each wafer mounted on the upper surface of the susceptor can be made uniform by adjusting the heat generation amount of the heater portion of the heating heater. Therefore, it is possible to form a uniform thin film having excellent characteristics.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An MOCVD apparatus which is an embodiment of the present invention will be described below with reference to FIGS. 1 is a vertical cross-sectional view showing the outline of the configuration, FIG. 2 is a horizontal cross-sectional view of the upper portion of the reaction tube, FIG. 3 is a plan view showing a mounting state of a GaAs wafer on a susceptor, and FIG. FIG. 6 is a plan view of the heater, and FIG. 5 is a connection diagram related to temperature control.

In FIGS. 1 to 5, 11 is MOCVD.
The apparatus is provided with a vertical cylindrical reaction tube 12 made of stainless steel, the upper end of which is closed, and a lower case 13 which is hermetically attached to the lower opening of the reaction tube 12. The lower case 13 is provided with a susceptor 14 having a diameter of 185 mm so as to face the lower opening of the reaction tube 12. On the upper surface of the susceptor 14, seven GaAs wafers 15 having a diameter of 2 inches are horizontally mounted. It is like this.

On the upper portion of the cylindrical side wall 16 of the reaction tube 12, the side wall 1 is provided at a position symmetrical with respect to the central axis of the reaction tube 12.
A pair of supply nozzles 17, 17 for delivering the raw material gas are attached so as to be in the same rotation direction along the inner peripheral surface of the nozzle 6. Then, for example, InGa is supplied to the supply nozzles 17 and 17.
AsH ₃ , PH ₃ , (CH ₃ ) for manufacturing a compound semiconductor substrate for forming a semiconductor device of a P light emitting diode
A raw material gas such as ₃ Ga, (CH ₃ ) ₃ Al, (CH ₃ ) ₃ In or the like is distributed and supplied from a raw material gas supply source (not shown) through a pipe 18 in which a valve is inserted. Further, at the bottom of the lower case 13, a gas exhaust port 19 for exhausting exhaust gas after vapor phase growth is provided.

Further, in the reaction tube 12, the supply nozzle 1
A metal straightening plate 20 having a thickness of 5 mm is provided so as to traverse the inside in the radial direction in the vicinity of the lower part of the opening of the holes 7 and 17, whereby the inside of the reaction tube 12 is divided into upper and lower parts and supplied. The upper space 21 is divided into the nozzles 17 and 17 opening side, and the lower space 22 is divided into the susceptor 14 side. The rectifying plate 20 has a diameter of 3 m which penetrates in a direction orthogonal to the upper surface of the susceptor 14 so that the aperture ratio is 10%.
A large number of m through holes 23 are formed substantially evenly. 2
Reference numeral 4 is a cooling mechanism provided on the outer wall for cooling the inside of the reaction tube 12.

On the other hand, the susceptor 14 is a GaAs wafer 1.
On the upper surface portion on which the 5 is placed, a recess 26 having a shelf 25 having substantially the same shape as the GaAs wafer 15 and having a depth similar to the thickness of the GaAs wafer 15 is formed.
The GaAs wafer 15 is placed on the shelf 25 of No. 6 so that the entire outer peripheral edge portion is placed about 3 mm. Then, between the recess 26 and the lower surface of the GaAs wafer 15 placed on the recess 26, about 1
A space 27 of about 2 mm is formed.

The lower portion of the susceptor 14 is supported by the cylindrical portion of the susceptor holder 28, and is rotationally driven by a driving device (not shown). A heating portion 29 is fixed inside the susceptor holder 28 in the vicinity of the lower portion of the susceptor 14, and the heating portion 29 is divided into an inner heater portion 30 and an outer heater portion 31 and is heated in the shape of a flat disc. The heater 32 is installed so as to be parallel to the upper surface of the susceptor 14, and the power supply terminal 3 is controlled by the control unit 33.
Ga placed on the upper surface while controlling the heat generation amount of the heater 32 by adjusting the power supply amount to 0a, 30b, 31a, 31b.
The As wafer 15 can be heated. In addition, in the heating part 29, both heater parts 30 of the heater 32,
Thermocouples 34 and 35 are embedded in the vicinity of 31 so that the temperature in the vicinity of the heater portions 30 and 31 can be measured.

Further, on the upper side wall of the lower case 13, a temperature measuring tube 37 formed of a quartz tube or the like driven by a driving mechanism 36 is attached to an O-ring 38 or the like in a gas-tight manner by GaA.
An insertion portion 39 is provided above and below the wafer 15. The temperature measuring tube 37 inserted through the inserting portion 39 has a thermocouple 40 housed in the tip thereof, and the temperature measuring tube 37 is radially moved in the radial direction A in a plane parallel to the upper surface of the susceptor 14 by the drive mechanism 36. Further, the temperature in the vicinity of the upper surface of the GaAs wafer 15 can be measured by scanning while moving forward and backward from the upper central portion of the susceptor 14 to the outer peripheral portion.

The control unit 33 is also provided with a controller 41 capable of presetting the temperature in the vicinity of the upper surface of the GaAs wafer 15. Further, a temperature measuring device 42 is connected to the controller 41. From the temperature measuring device 42 to the controller 41, a temperature signal corresponding to the temperature measured by the thermocouple 40 housed in the temperature measuring tube 37 and a driving mechanism. Temperature measuring tube 3 from 36
Thermocouple 40 obtained by calculating the amount of input and output of 7
A measurement position signal corresponding to the position where the temperature is measured is output.

Further, the control unit 33 includes an inner heater portion 30 and an outer heater portion 3 of the heater 32 of the heating unit 29.
The heating regulators 43 and 44 for respectively controlling the heat generation amount of 1 and the thermocouples 34 and 35 are connected, and the measured temperatures in the vicinity of both the heater portions 30 and 31 measured by these are input and the controller 41 from the controller 41 Heating controller 43,4 by signal
The temperature controllers 45 and 46 for outputting the heating control amount of No. 4 are provided.

From the controller 41, a temperature difference signal corresponding to the temperature difference between the temperature near the upper surface of the GaAs wafer 15 preset in the controller 41 and the measurement temperature of the thermocouple 40 is measured position signal. Together with this, the temperature is output to the temperature controllers 45 and 46.

Further, as not shown, MO
The CVD apparatus 11 has a clean bench provided above the reaction tube 12, and the susceptor 14 has a GaAs wafer 1
A driving device, a control device, and the like for moving the reaction tube 12 up and down when the reaction tube 5 is placed or when the inside of the reaction tube 12 is cleaned are provided.

In order to stack a multi-layered thin film on the surface of the GaAs wafer 15 having the above-described structure, first, the reaction tube 12 is lifted up, and the seven GaAs wafers 15 are placed in the recess 26 on the upper surface of the susceptor 14. Then, the reaction tube 12 and the lower case 13 are airtightly combined again to make the inside of the reaction tube 12 hermetically sealed. Then, the inside of the reaction tube 12 is depressurized to about several tens Torr, and the GaAs wafer 15 placed on the upper surface of the susceptor 14 is rotated by 600 to 800 by the heater 32 incorporated therein while rotating the susceptor 14.
Heat to a predetermined temperature of about ° C.

When heating the GaAs wafer 15,
The temperature in the vicinity of the directly upper surface of the GaAs wafer 15 is set in advance in the controller 41 of the controller 33. Then, the driving mechanism 36 drives the temperature measuring tube 37 so that the tip of the temperature measuring tube 37 is positioned in the vicinity of the upper surface of the GaAs wafer 15 in the central portion of the susceptor 14, and the temperature at this position is measured by the thermocouple 40. And a position signal are input to the controller 41 via the temperature measuring device 42.

At this time, if there is a difference between the measured temperature and the set temperature, the temperature controller 45 outputs a heating adjustment amount based on the difference, and the heating controller 43 causes the heater 32 to heat.
The calorific value of the inner heater portion 30 is adjusted. By this adjustment, the GaAs mounted on the central portion of the susceptor 14
The temperature near the upper surface of the wafer 15 becomes the set temperature.

Further, the driving mechanism 36 drives so that the tip of the temperature measuring tube 37 is positioned near the surface of the GaAs wafer 15 outside the susceptor 14, and the thermocouple 40 also measures the temperature at this position. . Here again, the measured temperature signal and the position signal are sent to the controller 4 via the temperature measuring device 42.
If there is a difference between the measured temperature and the set temperature, the heating controller 46 outputs the heating adjustment amount based on the difference, and the heating controller 44 outputs the heating adjustment amount.
The heating value of 1 is adjusted.

By this adjustment, the temperature in the vicinity of the directly upper surface of the GaAs wafer 15 placed on the outer portion of the susceptor 14 becomes the set temperature. In this way, the temperature from the central portion to the outer peripheral portion of the susceptor 14 is equalized. The temperature near the heater portions 30 and 31 when the temperature near the upper surface of the GaAs wafer 15 reaches the set temperature is measured by the thermocouples 34 and 35 and the temperature controller 4
5, 46 are stored.

Then, when the temperature in the vicinity of the upper surface of the GaAs wafer 15 reaches the set temperature, the temperature measuring tube 37 is retracted by the driving mechanism 36 so that it does not project from the inner wall of the lower case 13 and the source gas Do not block the flow of air inside the. After that, the thermocouples 34, 35
The temperature in the vicinity of each heater portion 30 and 31 of the heater 32 is measured by, and the amount of heat generated in each heater portion 30 and 31 is heated based on the measured temperature and the temperature stored in the temperature controllers 45 and 46. The temperature is adjusted by the adjusters 43 and 44 so that the temperature in the vicinity of the upper surface of the GaAs wafer 15 becomes the set temperature.

Next, in order to form a first layer of n-type GaAs thin film on the surface of the GaAs wafer 15, the corresponding source gas valve is opened and the supply nozzle 1 is supplied through the pipe 18.
The raw material gas is supplied at a predetermined flow rate from 7 and 17 into the reaction tube 12 such that the flow direction is substantially tangential to the inner circumferential circle. The raw material gas supplied into the reaction tube 12 flows in the upper space 21 of the straightening plate 20 while rotating in the same direction along the inner peripheral surface of the reaction tube 12, and is mixed with the straightening plate 20.
Through the through hole 23, the flow is rectified so that the flow direction is the axial direction of the reaction tube 12, and evenly flows through the lower space 22 toward the susceptor 14.

The supplied source gas is evenly supplied to the upper surface of each GaAs wafer 15 having a high temperature to cause a thermal decomposition reaction, thereby forming a GaAs thin film. Then, the raw material gas is supplied until a predetermined film thickness is obtained, and the exhaust gas after the reaction is continuously discharged and recovered from the gas exhaust port 19.

Further, subsequently, in order to form the second layer of InGaAlP thin film on the upper surface of the first layer of n-type GaAs, the source gas valve required for forming the first layer of thin film is closed, Then, the valve for the source gas required to form the second layer is opened.

Then, the supply nozzle 1 is similarly supplied through the pipe 18.
A raw material gas corresponding to the inside of the reaction tube 12 is supplied from 7, 17. The supplied source gas is rectified by the rectifying plate 20,
It flows evenly on the susceptor 14, and GaA is generated by the thermal decomposition reaction.
A thin film of InGaAlP is formed on the upper surface of the thin film of s.
The raw material gas is supplied until a predetermined film thickness is obtained, and the exhaust gas after the reaction is continuously discharged and collected from the gas exhaust port 19. At this time, since the distance between the supply nozzles 17 and 17 and the susceptor 14 is not long, the source gas in the reaction tube 12 is switched in a short time, and the first thin film and
The formation of an impure thin film at the interface of the thin film of the layer is suppressed.

Similarly, by opening and closing the valve, the reaction tube 1
The source gas supplied to the inside of 2 is controlled,
A compound semiconductor substrate is manufactured by laminating a P thin film, an InGaAlP thin film, and a p-type GaAs thin film in multiple layers. In the process of stacking these layers, the source gas is switched within a short time, and the formation of an impure thin film is suppressed even at the interface between the thin films. In forming each thin film, the pressure in the reaction tube, the rotation speed of the susceptor, the growth time, the GaAs wafer temperature, the raw material gas species and the raw material gas amount are properly selected.

As described above, according to this embodiment, since the height of the reaction tube 12 does not have to be increased, the height of the entire apparatus including the MOCVD apparatus 11 and the clean bench is not increased. The number of GaAs wafers that can be placed on the susceptor is increased, which increases the number of processes per batch and improves the productivity.

Further, a pair of supply nozzles 17 and 17 are provided so that the raw material gas rotates in the same direction, and the inside of the reaction tube 12 further includes an upper space 21 on the side of the supply nozzles 17 and 17 and GaAs.
Lower space 22 on the susceptor 14 side on which the wafer 15 is placed
Since the rectifying plate 20 having a plurality of through holes 23 is provided so as to be divided into upper and lower parts, the flow of the raw material gas onto the susceptor 14 becomes uniform, and each GaAs wafer 1
The thin film laminated on No. 5 has good uniformity and composition. The opening ratio of the straightening plate 20 is 5% to 15%.
In this case, a thin film having good uniformity and composition is obtained, and if it is less than 5%, the delivery pressure of the raw material gas is increased.
%, The flow of the raw material gas in the lower space 22 becomes turbulent and the flow of the raw material gas onto the susceptor 14 is not uniform, and the thin film to be formed has good uniformity and composition. Was not.

Furthermore, the height of the reaction tube 12 does not increase,
Since the distance between the supply nozzles 17 and 17 and the susceptor 14 does not become long, the source gas in the reaction tube 12 is switched within a short time. The thin film can be grown by switching the source gas with high agility, and thus a compound semiconductor substrate in which the formation of an impure thin film at the interface of each thin film is suppressed can be manufactured. The characteristics of No. 2 were good and the manufacturing yield was also improved. Further, the amount of raw material gas required for laminating a predetermined thin film on the GaAs wafer 15 did not increase.

Furthermore, the GaAs wafer 15 is placed so that the outer peripheral edge portion is placed on the shelf 25 of the recess 26 formed on the upper surface of the susceptor 14, and a gap 27 is formed between the GaAs wafer 15 and the susceptor 14 on the lower surface side. As a result, the contact with the susceptor 14 is less likely to be affected and the heat radiation is uniformly received.

As a result, the occurrence of warpage is suppressed, and the temperature variation of several tens of degrees Celsius in the surface of the GaAs wafer 15 is reduced to several degrees Celsius or less, so that the thermal uniformity is improved. The variation in the thickness of the growth film is also from several tens% to several% or less, and in the element manufactured by this wafer, for example, the semiconductor laser, the variation in the oscillation wavelength is from ± 5 nm to ± 2 nm or less, and the characteristics are improved. The stay is also improved. Further, the GaAs wafer 15 placed in the recess 26 of the susceptor 14 during the film formation process is also prevented from scattering.

Further, the heating unit 29 is composed of heating heaters 32 which are divided into heaters whose temperature can be adjusted individually, and the temperature in the vicinity of the upper surface of the GaAs wafer 15 is controlled to a predetermined temperature. Even in the susceptor 14 in which the number of wafers 15 mounted is increased, the temperature distribution between the central portion and the outer peripheral portion is ± 5 ° C. to ± 1 ° C. or less, and the temperature distribution is uniform. Further, since the film formation can be performed uniformly in the central portion and the outer portion of the susceptor 14, the number of GaAs wafers 15 that can be formed at one time is increased and the productivity is improved. The setting of process conditions for film formation can be confirmed in a short time because the temperature near the immediate upper surface of the GaAs wafer 15 is easily obtained.

Although the MOCVD apparatus relating to the compound semiconductor substrate has been described in the above embodiment, the present invention is not limited to this and a chemical vapor deposition apparatus (CVD apparatus) for manufacturing another semiconductor substrate. The present invention can also be applied to any of the above, and can be appropriately modified and implemented without departing from the scope of the invention.

[0046]

As is apparent from the above description, according to the present invention, a plurality of through holes are formed so as to vertically divide the inside of the vertical cylindrical reaction tube into the source gas supply nozzle side and the wafer susceptor side. By providing the straightening plate with the holes, the height of the entire device is not increased while productivity is improved, and an impure thin film can be formed by abrupt switching of the raw material gas. It is possible to obtain effects such as suppression and formation of a good thin film.

[Brief description of drawings]

FIG. 1 is a vertical plan view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an upper portion of a reaction tube according to an embodiment of the present invention.

FIG. 3 shows Ga on a susceptor according to an embodiment of the present invention.
It is a top view which shows the mounting state of an As wafer.

FIG. 4 is a plan view showing a heater according to an embodiment of the present invention.

FIG. 5 is a connection diagram relating to temperature control in one embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a schematic configuration of a conventional example.

FIG. 7 is a plan view showing a mounting state of a GaAs wafer on a susceptor in a conventional example.

FIG. 8 is a longitudinal sectional view of an essential part showing a state of a GaAs wafer at the time of film formation in a conventional example.

FIG. 9 is a temperature distribution diagram of a susceptor in a conventional example.

[Explanation of symbols]

 12 ... Reaction tube 13 ... Lower case 14 ... Susceptor 15 ... GaAs wafer 16 ... Side wall 17 ... Supply nozzle 20 ... Rectifier plate 21 ... Upper space 22 ... Lower space 23 ... Through hole 29 ... Heating part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomio Minohoshi 25-1, Ekimaehonmachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Toshiba Microelectronics Co., Ltd.

Claims (6)

[Claims] 1. A vertical cylindrical reaction tube having a closed upper end, a supply nozzle attached to an upper portion of a side wall of the reaction tube to deliver a raw material gas into the reaction tube, and an attachment of the supply nozzle. A rectifying plate having a plurality of through-holes provided below the site so as to divide the inside of the reaction tube into upper and lower parts, a susceptor arranged below the rectifying plate, and a susceptor on the susceptor. A semiconductor chemical vapor deposition apparatus comprising: a heating unit for heating a mounted wafer. 2. At least two supply nozzles are provided,
2. The semiconductor chemical vapor deposition apparatus according to claim 1, wherein the source gas is delivered from the supply nozzle in the same direction along the inner peripheral surface of the side wall of the reaction tube. 3. The opening ratio of the current plate having the through holes is 5
2. The chemical vapor deposition apparatus for semiconductors according to claim 1, wherein 4. The heating unit comprises a heating heater including a plurality of heater portions, and each of the heater portions is provided so that the amount of heat generated can be adjusted. Semiconductor chemical vapor deposition equipment. 5. A susceptor for mounting a wafer on the upper surface of the reaction tube is provided below the reaction tube, and a heating unit for heating the susceptor from the lower side is provided so that predetermined film growth is performed on the upper surface of the wafer. In the semiconductor chemical vapor deposition apparatus, a temperature measuring unit for measuring the temperature of the upper portion of the wafer placed on the upper surface of the susceptor while scanning is provided, and the heating unit includes a heating unit including a plurality of heater units. A semiconductor chemical vapor deposition apparatus comprising a heater, wherein the calorific value of each heater portion is adjusted based on the temperature measured by the temperature measuring unit. 6. The semiconductor chemical vapor deposition apparatus according to claim 1, wherein the susceptor has a gap between the susceptor and the lower surface of the mounted wafer.