JP2001010894A - Susceptor for crystal growth and crystal growth device, and epitaxial wafer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject device intended for the epitaxial growth of a single crystal on the surface of a substrate by making a reactant gas flow on the surface of the substrate at elevated temperatures while making the heat content per unit area of the peripheral rim of the substrate mount area of a susceptor lower than that at the central part of the mount area so as to improve both the film thickness uniformity and impurity concentration uniformity in the single crystal plane. SOLUTION: This device works as follows: a silicon substrate W is placed on a recess provided on the mount area 12a of a disc-shaped susceptor 12 made of carbon or the like and turned via a rotating shaft member inserted into an engagement hole 12d provided on the reverse side of the peripheral area 12b; a reactant gas comprising silane gas and dopant gas is then made to flow on the surface of the substrate W while heating the substrate W to e.g. about 1,130 deg.C by the aid of halogen lamps or the like disposed therearound to accomplish epitaxial growth of a silicon single crystal on the substrate W; in producing the epitaxial wafer, an annular groove 12c is provided on the peripheral rim of the mount area 12a of the susceptor 12, or a projection is provided at the central part to make the heat content of the peripheral rim lower than that at the central part, thereby making the temperature of the peripheral rim of the substrate W lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal growth susceptor for supporting a substrate when performing epitaxial growth on a substrate such as a silicon wafer, and a crystal growth apparatus using the same.
And an epitaxial wafer and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a silicon wafer for MOS devices, a silicon substrate having an extremely low resistivity has been used.
An epitaxial wafer in which a single crystal silicon thin film (epitaxial layer) is vapor-phase grown at a predetermined impurity concentration is used. This epitaxial wafer is made of COP (Crystal Originated Part
icle) can be suppressed, the yield of the gate oxide film of the MOS device can be improved, and excellent characteristics such as reduction of parasitic capacitance, prevention of soft error, and improvement of gettering ability can be provided.

In the production of epitaxial silicon, a single wafer type epitaxial crystal growth apparatus has been mainly used instead of a conventional batch type with the increase in diameter of a silicon wafer. A caliber version has been developed. In this single-wafer apparatus, a silicon substrate is placed on one susceptor disposed in a horizontal state in a chamber, and the susceptor is mainly heated by a heating source such as an infrared lamp disposed around the susceptor. The silicon substrate placed on the substrate is heated to a high temperature.

[0004] While rotating the susceptor, a gaseous phase is grown by flowing a reaction gas onto a silicon substrate in a high temperature state. As shown in FIG. 7, the conventional susceptor 1 is formed by forming carbon having a surface coated with silicon carbide into a circular flat plate, and a quartz-made fitting hole 1a formed on the lower surface thereof. The support part 2 is inserted and rotatably supported in the chamber.

[0005]

However, the above-mentioned conventional epitaxial crystal growing means has the following problems. That is, since higher yield and higher reliability are also required for epitaxial wafers, in particular, more uniform film thickness and resistance over the entire surface of the wafer are required. When examining the film thickness distribution of the epitaxial layer grown by the conventional means, as shown in FIG. 8A, there is a phenomenon that the peripheral portion becomes thicker than the central portion, and the distribution of the resistance value is examined. As shown in FIG. 8B, there is a phenomenon that the peripheral portion is lower than the central portion, and it is necessary to correct these non-uniformities. One of the factors that increase the thickness of the peripheral portion is considered to be due to the disturbance of the flow of the reaction gas in the peripheral portion,
In addition, one of the factors that lower the resistance value of the peripheral portion is as follows.
The so-called auto-doping phenomenon can be considered. This auto-doping phenomenon means that when an epitaxial layer is grown on a low-resistance silicon substrate to which boron is added at a high concentration, boron evaporated from the edge of the substrate is taken into the epitaxial layer on the peripheral edge of the surface, and the impurity concentration is increased. This is a phenomenon in which the resistance increases and the resistance value decreases. Since the thickness and resistance of the epitaxial layer are affected by the temperature and the flow of gas, etc., the power of the lamp is made relatively large at the center with respect to the periphery, or the upper part of the chamber is placed at the center of the wafer. Has been proposed to reduce the resistance value at the center by supplying boron from the substrate to make the resistance uniform. However, it has been difficult to improve the local uniformity of the outer peripheral portion by using only these methods.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a susceptor for crystal growth capable of improving in-plane film thickness uniformity and impurity concentration uniformity in epitaxial growth, and a crystal growth apparatus using the same. And an epitaxial wafer and a method of manufacturing the same.

[0007]

The present invention has the following features to attain the object mentioned above. That is, in the susceptor for crystal growth according to the first aspect, when a reaction gas is flowed on the substrate in a high temperature state to grow a crystal on the substrate surface, the substrate is heated while being mounted on the surface of the mounting region. In the plate-shaped susceptor for crystal growth, a technology is adopted in which the heat capacity per unit area of the peripheral portion of the mounting region is smaller than that of the central portion of the mounting region.

In this susceptor for growing a crystal, the peripheral portion of the mounting region has a smaller heat capacity per unit area than the central portion of the mounting region. As a result, the temperature of the mounted substrate becomes lower at the peripheral portion than at the central portion. That is,
Since the thickness of the epitaxial layer becomes thinner as the temperature becomes lower, the thickness of the peripheral portion is corrected to be thinner than the conventional one by the relatively low temperature, and the uniformity of the film thickness in the entire surface becomes higher. In addition, the resistance value of the epitaxial layer (especially when the dopant is boron) tends to increase as the temperature decreases (boron is hardly taken in), and at the same time, the temperature of the peripheral portion decreases and additional impurities (boron or the like) which emerge from the edge are reduced. ) Is reduced, the resistance value of the peripheral portion is corrected to be higher than before by the low temperature, and the uniformity of the resistance value over the entire surface is increased.

In the susceptor for growing a crystal according to the second aspect,
In the susceptor for crystal growth according to the first aspect, a technique is employed in which a peripheral portion of the placement region has a smaller thickness than a central portion of the placement region.

In this susceptor for crystal growth, the peripheral portion of the mounting region is thinner than the central portion of the mounting region, so that the heat capacity per unit area of the peripheral portion can be easily and accurately determined. It can be smaller than the central part.

In the susceptor for growing a crystal according to the third aspect,
The susceptor for crystal growth according to claim 1 or 2,
A technique in which a groove is formed on at least one of the front surface and the back surface of the peripheral portion of the placement region is adopted.

In this crystal growth susceptor, the peripheral portion of the mounting region has a groove formed on at least one of the front surface and the back surface, so that the thickness of the groove is reduced, and the unit of the entire peripheral portion is reduced. The heat capacity per area can be made smaller than that in the central part.

[0013] In the susceptor for crystal growth according to claim 4,
In the susceptor for crystal growth according to any one of claims 1 to 3, a technology in which a convex portion is formed on a back surface of a central portion of the placement region is adopted.

In this susceptor for growing a crystal, since the convex portion is formed on the back surface of the central portion of the mounting region, the thickness of the convex portion is increased, and the heat capacity per unit area of the central portion is reduced by the peripheral portion. The temperature of the peripheral portion can be relatively reduced.

[0015] In the susceptor for crystal growth according to the fifth aspect,
The susceptor for crystal growth according to any one of claims 1 to 4, wherein the heat capacity per unit area of the placement region is:
The technology set according to the in-plane distribution of radiant heat applied when the surface of the placement region is heated is adopted.

In this susceptor for growing a crystal, the heat capacity per unit area of the mounting region is set according to the in-plane distribution of radiant heat applied when the surface of the mounting region is heated. Even if the distribution of the radiant heat applied is uneven due to the heat distribution, the uniformity of the film thickness and the resistance value can be obtained with high accuracy by the heat capacity distribution in consideration of the intensity distribution. For example, when the distribution of the applied radiant heat is not uniform in the radial direction but changes, the thickness of the peripheral portion is changed in the radial direction in response to the change to further improve the in-plane uniformity of the above characteristics. It is possible to set a suitable heat capacity.

According to a sixth aspect of the present invention, there is provided a crystal growth apparatus for mounting a substrate on a susceptor to bring the substrate to a high temperature state and flowing a reaction gas over the substrate to grow a crystal on the substrate surface. The technique which is the susceptor for crystal growth according to any one of claims 1 to 5 is adopted.

In this crystal growth apparatus, since the susceptor is the susceptor for crystal growth according to any one of claims 1 to 5, an epitaxial wafer having excellent in-plane uniformity of film thickness and resistance value can be manufactured. Can be.

A method for producing an epitaxial wafer by epitaxially growing a crystal film on a surface of a substrate according to claim 7, wherein the substrate is used for crystal growth according to any one of claims 1 to 5. A technique is employed in which the crystal is placed on a susceptor to bring it to a high temperature state and a reaction gas is flowed to grow the crystal on the substrate surface.
In the method for manufacturing an epitaxial wafer according to claim 8, the crystal wafer is formed by epitaxially growing a crystal film on the surface of the substrate. Advanced technology is adopted.

In this epitaxial wafer and the method of manufacturing the same, the substrate is placed on the crystal growth susceptor to be in a high temperature state, and the reaction gas is flowed to grow the crystal on the substrate surface. Excellent in-plane uniformity of film thickness and resistance value.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a susceptor for crystal growth, a crystal growth apparatus using the susceptor, an epitaxial wafer and a method of manufacturing the same according to the present invention will now be described with reference to FIG.
This will be described with reference to FIG. In these figures, reference numeral 11 denotes a chamber, 12 denotes a susceptor, and 13 denotes a susceptor rotating shaft member.

FIGS. 1 and 2 show a single-wafer epitaxial crystal growing apparatus according to the present embodiment. The epitaxial crystal growing apparatus includes a quartz chamber 11 which is a hollow circular hermetic container, and a chamber 11 made of quartz. The susceptor 12 includes a susceptor 12 installed in the chamber 11 and a susceptor rotating shaft member 13 made of quartz for rotatably supporting the susceptor 12. And a halogen lamp for heating the silicon substrate W, and a pyrometer or thermocouple arranged above and below the chamber 11 for measuring the temperature of the susceptor 12.

The apparatus for growing an epitaxial crystal includes a gas introducing portion 16 and a gas discharging portion 17 of a reaction gas provided on the outside of the chamber 11 so as to face each other. A wafer loading / unloading unit for loading / unloading a silicon substrate W from outside onto a susceptor 12 in the chamber 11. The susceptor rotation shaft member 13 is connected to a rotation drive mechanism (not shown).

The susceptor 12 is formed of carbon whose surface is covered with a silicon car band.
As shown in FIGS. 3 and 4, a disk-shaped mounting area 12 a on which a silicon substrate W is mounted, and a mounting area 12 a
And a peripheral region 12b integrally formed in an annular shape on the outer periphery of the device. The surface of the placement area 12a and the peripheral area 1
The surface of the mounting region 12a is provided with a step about the thickness of the silicon substrate W.
Is set so that the surface of the peripheral region 12b and the surface of the silicon substrate W are located substantially on the same plane.

On the back surface of the mounting area 12a, an annular groove 12c having a rectangular cross section is formed coaxially with the susceptor 12 at the peripheral edge thereof. That is, the thickness of the annular groove 12c is thinner than the center of the mounting region 12a, and in the present embodiment, the thickness of the annular groove 12c is set to about 約 of the center. Fitting holes 12d are formed on the back surface of the peripheral region 12b in the circumferential direction, and the susceptor rotating shaft member 13 is inserted into each fitting hole 12d to support the susceptor 12.

The gas introducing section 16 is connected to a supply source (not shown) of a reaction gas. The reaction gas used in the present embodiment is trichlorosilane as a source gas, diborane as a P dopant gas, and a carrier gas as a carrier gas. It consists of hydrogen gas and is supplied into the chamber 11 from the gas inlet 16. The gas discharge unit 17 is connected to a reaction gas processing device (not shown) or the like.
The reaction gas used inside is discharged and processed. As shown in FIG. 3, a silicon substrate W on which epitaxial growth is performed is formed by CVD on a back surface of a low-resistance substrate (0.01 to 0.03 Ω · cm) W0 doped with boron at a high concentration.
An MOS layer provided with an LTO (Low Temperature Oxide) as an oxide film is used, and an epitaxial layer (crystal film) E is grown on the surface.

Next, a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the susceptor, an epitaxial wafer and an epitaxial crystal growth method in the first embodiment of the method for manufacturing the same will be described.

First, a silicon substrate W to be subjected to epitaxial growth is loaded into the chamber 11 from the wafer loading / unloading section, and is placed on the surface of the placement area 12a of the susceptor 12. Thereafter, the temperature of the silicon substrate W is raised to a predetermined temperature (11
(30 ° C.) by a halogen lamp, and hydrogen baking is performed to remove a natural oxide film and a surface defect. The silicon substrate W is in a high temperature state mainly due to heat from the susceptor 12 heated by infrared light from a halogen lamp.

Subsequently, a reaction gas is supplied from the gas inlet 16 into the chamber 11, and epitaxial growth is performed on the surface of the silicon substrate W. At this time, the reaction gas flows in one direction from the gas inlet 16 to the gas outlet 17 opposed thereto, and is discharged from the gas outlet 17 to the outside after being subjected to crystal growth on the surface of the silicon substrate W. During growth, the susceptor 12 and the silicon substrate W are rotated via the susceptor rotation shaft member 13 by a rotation drive mechanism. As shown in FIG. 3, after the epitaxial layer E is epitaxially grown on the surface to a predetermined thickness, the supply of the reaction gas is stopped and the temperature is lowered. Is taken out of the chamber 11.

In this embodiment, since the annular groove 12 is formed in the peripheral portion of the mounting region 12a of the susceptor 12, the heat capacity per unit area of the peripheral portion is smaller than that of the central portion of the mounting region 12a. . Therefore, when heated, the temperature of the peripheral portion becomes lower than that of the central portion, and the temperature of the silicon substrate W to be placed also becomes lower than that of the central portion.

That is, the epitaxial layer E to be grown
Since the film thickness becomes smaller as the temperature becomes lower, the film thickness at the peripheral portion is corrected to be thinner than before by the relatively low temperature, and the uniformity of the film thickness over the entire surface becomes higher. Also,
When the temperature is low, the resistance of the epitaxial layer E tends to increase because boron is hardly taken in, and the temperature of the peripheral portion is lowered, so that the boron taken out from the edge of the silicon substrate W is reduced. The resistance value of the portion is corrected higher than before by the low temperature, and the uniformity of the resistance value over the entire surface becomes higher. In the present embodiment, the resistivity ρ of the epitaxial layer E is set to 9 to 11Ω · c.
The epitaxial wafer W controlled to m is manufactured.

Next, a second embodiment of the crystal growth susceptor according to the present invention, a crystal growth apparatus using the same, an epitaxial wafer and a method of manufacturing the same will be described with reference to FIG.

The difference between the second embodiment and the first embodiment is that in the first embodiment, the mounting area 12a of the susceptor 12
An annular groove 12c having a rectangular cross section is formed in the peripheral portion, but in the second embodiment, as shown in FIG. 5A, the groove depth is set to a radius in the peripheral portion of the mounting region 21a of the susceptor 21. The point is that an annular groove 21b that gradually becomes deeper outward in the direction is formed.

That is, in this embodiment, when the distribution of the radiant heat applied to the surface of the mounting area 21a is uneven due to the arrangement of the lamps, etc., the annular groove 21b is set to set the heat capacity corresponding to the intensity distribution. Is formed, the thickness of the peripheral portion of the mounting region 21a is gradually changed outward in the radial direction so as to be tapered, and the heat capacity per unit area in the radial direction is controlled. This makes it possible to improve the in-plane uniformity of the film thickness and the resistance value even if the distribution of the radiant heat is uneven.

As another example of this embodiment, as shown in FIG. 5B, according to the in-plane distribution of radiant heat applied when the surface of the mounting area 31a of the susceptor 31 is heated. The annular groove 31b at the peripheral edge of the mounting area 31a may be formed so as to be gradually shallower outward in the radial direction. FIG.
In the example shown in (a), since the heat capacity is set so as to gradually decrease outward in the radial direction by the annular groove 21b, a rapid temperature difference does not occur in the radial direction, and slip occurs in the silicon substrate W. Can be prevented.

Next, a third embodiment of the crystal growth susceptor according to the present invention, a crystal growth apparatus using the same, an epitaxial wafer and a method for manufacturing the same will be described with reference to FIG.

The difference between the third embodiment and the first embodiment is that in the first embodiment, the mounting area 12a of the susceptor 12
Although the annular groove 12c is formed in the peripheral portion, in the third embodiment, as shown in FIG. 6, a convex portion 41b projecting to the rear surface side is formed in the center of the mounting area 41a of the susceptor 41. Is a point.

In the third embodiment, a fitting hole 41c for inserting the support pin (support rod) 13c is formed at the center of the projection 41b, that is, at the center of rotation (the center position of the mounting area 41a). Is different from the first embodiment. In addition,
A fitting hole 41e for inserting the susceptor rotating shaft member 13 is formed on the back surface of the peripheral region 41d, as in the first embodiment. Therefore, the susceptor rotating shaft member 13
Has one support pin 13c erected at the center.

In this embodiment, since the convex portion 41b is formed on the back surface at the center of the mounting area 41a, the convex portion 41b
Is thicker, the heat capacity per unit area of the central portion can be made larger than that of the peripheral portion, and the temperature of the peripheral portion is relatively lower. Also, the fitting hole 41c is formed in the convex portion 41b.
Is formed, even when the susceptor is rotated with the support pin 13c inserted into the fitting hole 41c during growth, eccentricity is prevented because the rotation center is supported by the support pin 13c, and eccentricity is prevented. Nonuniformity of the film thickness and the resistance value can be prevented. Further, a decrease in the heat capacity of the fitting hole 41c can be compensated for as a whole of the projection 41b, and a decrease in the temperature at the center can be suppressed.

The present invention includes the following embodiments. In each of the above embodiments, the annular groove is formed on the back surface of the mounting area, but may be formed on the front surface.
In this case, the annular groove is formed in consideration of a change in the temperature distribution due to a decrease in the contact area with the silicon substrate to be mounted. In addition, although the susceptor is mainly heated by infrared rays using a halogen lamp as a heating method, another heating method or a heating source may be adopted. For example, the susceptor may be mainly heated by high-frequency heating using a high-frequency induction coil.

Further, in each of the above embodiments, the present invention is applied to a single-wafer type epitaxial apparatus. However, the present invention is not limited to this, and may be applied to other types (various batch types, etc.). Further, although one annular groove is formed to reduce the thickness of the peripheral portion of the mounting region, a groove having a shape other than the annular shape may be formed. For example, a groove composed of a plurality of dot holes or a linear groove extending radially in a radial direction may be formed. Further, a groove composed of a plurality of annular grooves may be used.

[0042]

According to the present invention, the following effects can be obtained.
According to the susceptor for crystal growth according to the first aspect, the peripheral portion of the mounting region has a smaller heat capacity per unit area than the central portion of the mounting region. The temperature is lower than at the center, and the thickness of the epitaxial layer can be made uniform as compared with the case where the temperature distribution is uniform over the entire surface. Further, since the temperature of the peripheral portion is lowered and the amount of added impurities coming out from the edge is reduced, the resistance of the peripheral portion is prevented from being reduced, and the uniformity of the resistance value over the entire surface can be increased.

According to the susceptor for growing a crystal according to the second aspect, the peripheral portion of the mounting region is thinner than the central portion of the mounting region, so that the heat capacity per unit area of the peripheral portion is reduced. The thickness can be easily and accurately adjusted to be smaller than the central portion by adjusting the thickness, and the uniformity of the film thickness and the resistance value can be further improved by an appropriate heat capacity distribution.

According to the susceptor for crystal growth according to the third aspect, since the groove is formed on at least one of the front surface and the back surface of the mounting region, the thickness of the groove at the position of the groove is reduced. The heat capacity per unit area of the entire peripheral portion can be made smaller than that of the central portion, and an appropriate heat capacity distribution can be obtained with a simple configuration.

According to the susceptor for crystal growth according to the fourth aspect, since the convex portion is formed on the back surface of the central portion of the mounting region, the heat capacity per unit area of the central portion having the convex portion is larger than that of the peripheral portion. As a result, the temperature of the peripheral portion becomes relatively low, so that the in-plane film thickness and the resistance value can be made uniform.

According to the susceptor for crystal growth according to the fifth aspect, the heat capacity per unit area is set according to the in-plane distribution of radiant heat applied when the surface of the mounting region is heated. Even if the distribution of the radiant heat applied due to the arrangement of the lamps is biased, the heat capacity is set corresponding to the intensity distribution, so that the in-plane uniformity of the film thickness and the resistance value can be further improved.

According to the crystal growth apparatus of the sixth aspect, since the susceptor is the susceptor for crystal growth according to any one of the first to fifth aspects, an epitaxial layer having excellent in-plane uniformity of film thickness and resistance value is provided.・ Wafer can be manufactured stably and with high yield, and high quality epitaxial wafers can be supplied at low cost.

According to the method for manufacturing an epitaxial wafer according to the seventh aspect and the method for manufacturing an epitaxial wafer according to the eighth aspect, the substrate is placed on the susceptor for crystal growth to a high temperature state, and the reaction gas is flowed. Since the crystal is grown on the substrate surface, the in-plane uniformity of the thickness and the resistance value of the crystal film is excellent, and the yield can be improved in the subsequent semiconductor manufacturing process.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the same, and an epitaxial crystal growth apparatus according to a first embodiment of an epitaxial wafer and a method for manufacturing the same.

FIG. 2 is a cross-sectional view showing a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the same, an epitaxial wafer, and a susceptor in a first embodiment of a method for manufacturing the same.

FIG. 3 shows a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the susceptor, an epitaxial wafer and an epitaxial wafer according to the first embodiment of the manufacturing method thereof.
It is sectional drawing which shows a wafer.

FIG. 4 is a cross-sectional view of main parts showing two examples of a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the same, an epitaxial wafer, and a susceptor in a second embodiment of a method for manufacturing the same.

FIG. 5 is a cross-sectional view showing a susceptor according to a third embodiment of the present invention for a crystal growth susceptor, a crystal growth apparatus using the same, an epitaxial wafer, and a method of manufacturing the same.

FIG. 6 is a cross-sectional view showing a susceptor for crystal growth according to the present invention, a crystal growth apparatus using the same, an epitaxial wafer and a susceptor in a conventional example of a method for manufacturing the same.

FIG. 7 is a graph showing the distribution of resistivity and layer thickness in the radial direction of an epitaxial layer in a crystal growth susceptor according to the present invention, a crystal growth apparatus using the susceptor, an epitaxial wafer and a conventional example of a method of manufacturing the same. It is.

[Explanation of symbols]

11 Chamber 12, 21, 31, 41 Susceptor 12a, 21a, 31a, 41a Mounting Area 12c, 21b, 31b Annular Groove 41b Convex W Silicon Substrate (Epitaxial Wafer After Growth)

Continuing on the front page (72) Inventor Tomonori Yamaoka 1-5-1, Otemachi, Chiyoda-ku, Tokyo Mitsui Material Silicon Co., Ltd. (72) Inventor Hiroshi Shinyashiki 5-1-1, Otemachi, Chiyoda-ku, Tokyo 3 Rishi Material Silicon Co., Ltd. (72) Inventor Kazuo Tezuka 1-1-5 Otemachi, Chiyoda-ku, Tokyo F-Term (reference) 4G077 AA03 AB02 BA04 DB05 EA06 EB01 EB04 ED04 EG04 HA06 5F045 AC05 AF03 BB02 BB04 DP04 DP28 EB15 EK03 EK14 EM02

Claims (8)

[Claims] When a crystal is grown on a substrate surface by flowing a reaction gas onto a substrate in a high temperature state, a plate-shaped crystal growth susceptor is heated while the substrate is mounted on the surface of the mounting area. A susceptor for crystal growth, wherein a heat capacity per unit area of the peripheral portion of the mounting region is smaller than that of a central portion of the mounting region. 2. The susceptor for crystal growth according to claim 1, wherein the peripheral portion of said mounting region has a thickness smaller than that of a central portion of said mounting region. 3. The susceptor for crystal growth according to claim 1, wherein a groove is formed in at least one of a front surface and a back surface of the peripheral portion of the placement region. . 4. The susceptor for crystal growth according to claim 1, wherein a projection is formed on a back surface of a central portion of the placement region. 5. The susceptor for growing a crystal according to claim 1, wherein the heat capacity per unit area of the placement region is a radiant heat applied when the surface of the placement region is heated. A susceptor for growing a crystal, which is set according to an in-plane distribution. 6. A crystal growth apparatus for placing a substrate on a susceptor to bring it to a high temperature state, flowing a reaction gas over the substrate to grow a crystal on the substrate surface, wherein the susceptor is any one of claims 1 to 5. A crystal growth apparatus, which is the susceptor for crystal growth according to any one of the above. 7. A method for producing an epitaxial wafer by epitaxially growing a crystal film on a substrate surface, wherein the substrate is placed on the susceptor for crystal growth according to any one of claims 1 to 5. A method for producing an epitaxial wafer, comprising: bringing a crystal to a high temperature state and flowing a reaction gas to grow the crystal on the substrate surface. 8. An epitaxial wafer having a crystal film epitaxially grown on a substrate surface, wherein the crystal is grown on the substrate by the method of manufacturing an epitaxial wafer according to claim 7. Wafer.