JPH11278985A - Production of single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a single crystal, capable of obtaining the single crystal having reduced defects by disposing at least one low temperature region on a seed crystal-growing surface in the early period of the single crystal growth to control the production of the growth nucleus in the early period of the single crystal growth and subsequently uniforming the temperature distribution of the growth surface in the middle and last periods of the single crystal growth. SOLUTION: A reaction vessel comprises a graphite crucible 1 and a graphite lid 2. Silicon Carbide raw material powder 3 is disposed in the graphite crucible 1, and a seed crystal 4 is disposed on the graphite lid 2 further used as a seed crystal-loading portion. A bored portion 6 is disposed in the graphite lid 2 to locally cool the seed crystal growth surface. The growth of the seed crystal 4 is carried out by controlling the temperature of a graphite heat generation resister and the pressure of an inert gas, etc. A place near to the bored portion 6 is cooled in comparison with its peripheral portion by the radiation of heat. It is thereby forecast that the growth density of the grown nucleus is enhanced in the central portion of the seed crystal 4. The peripheral portion of the seed crystal 4 is governed by a step flow growth mechanism. The obtained single crystal ingot is formed on one crystal surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a single crystal, and more particularly, to a method for producing a single crystal by growing the single crystal on a seed crystal substrate set on a seed crystal mounting portion. By providing at least one relatively low temperature region on the growth surface of the seed crystal at the initial stage of crystal growth, generation of a plurality of growth nuclei is prevented, thereby making it possible to produce a single crystal with few crystal defects. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Development of a high quality, large area silicon carbide (SiC) single crystal substrate as a high performance semiconductor material is required. In order to manufacture an integrated circuit, a single crystal substrate having few crystal defects is required. However, when a single crystal is grown on a seed crystal by a sublimation method or a vapor phase growth method, the single crystal is grown on a just angle seed crystal. When a crystal is grown, a single crystal grows from a plurality of growth nuclei, so that a portion corresponding to a joint of each crystal is generated, which is one cause of generating a crystal defect. Conventionally, in order to prevent the generation of the crystal defects, the temperature distribution of the growth surface and the amount of the reaction gas supplied to the growth surface are adjusted, and furthermore, the growth nuclei are controlled in combination with the off-angle substrate to control the growth nuclei. Reduction was attempted. Specific examples are shown below.

[0003] Japanese Patent Laid-Open Publication No. 4-16597 (sharp) A hexagonal silicon carbide seed crystal whose main growth plane orientation is inclined by 1 to 10 degrees from the [0001] direction is used. SUMMARY OF THE INVENTION The amount of reaction gas supplied onto an off-angle substrate is increased in proportion to the height of a growth step. SUMMARY OF THE INVENTION A temperature gradient is provided from one edge of a seed crystal substrate to the other opposite edge, and the seed crystal substrate is grown using a growth mechanism mainly based on step growth. A substrate having a crystal growth plane inclined at 5 to 30 degrees from the {0001} plane is used. Japanese Patent Application Laid-Open No. 8-59389 (Matsushita Electric) Singular points (projections, dents, impurities) on the seed crystal growth surface
Is introduced and grown. A step of cutting out a single crystal growth portion other than the portion grown on the singular point. Japanese Patent Application Laid-Open No. 5-330995 (Sharp) Although a lid having a counterbore structure is shown, its effect is not mentioned. Same as Japanese Patent Publication No. 3-50118 (North Carolina State University). The countersink structure is only specified as an optical aperture for temperature measurement.

[0004]

In the prior art, there is a possibility that nuclei may be formed at various points in the growth plane depending on the growth conditions, and it is difficult to completely control the growth nucleation. Therefore, defects cannot be significantly reduced. Further, since an off-angle substrate must be manufactured, there is a problem that the production yield of the seed crystal substrate is reduced. In the prior art, it is difficult to strictly control the amount of the reaction gas in proportion to the height of the growth step, and there is the same concern as in the prior art. The conventional technique has better control of growth nucleation than the conventional technique, but the seed crystal substrate is arranged at a position deviated in one direction from the center of the lid of the reactor, so that the diameter of the grown crystal becomes larger. In such a case, a large crucible and a reaction furnace are required, which is disadvantageous in terms of cost. Furthermore, since the middle and late stages of growth also exhibit a temperature distribution having a temperature gradient substantially equal to that of the initial stage of growth, they exhibit a biased growth facet and are unsuitable for uniform doping of impurities for controlling electrical characteristics. In the prior art, it is difficult to control the growth nucleus only by the shape singularity, and there is the same concern as in the prior art. In the prior art, a lid having a counterbore structure is used, but the usage of the lid is, for example, an optical opening for temperature measurement. For this purpose, it is desirable that the opening be large, but it is difficult to control the nucleation by making the growth surface spot-like in temperature with a large opening.

An object of the present invention is to solve the above-mentioned problems of the prior art. It is an object of the present invention to control the generation of growth nuclei in the initial stage of single crystal growth and to suppress the generation of a plurality of growth nuclei. It is an object of the present invention to provide a method for producing a single crystal which can obtain a single crystal with few defects and can easily increase the diameter of a grown crystal.

[0006]

That is, a method of manufacturing a single crystal according to the present invention comprises a method of manufacturing a single crystal by growing the single crystal on a seed crystal substrate set on a seed crystal mounting portion. At least one relatively low-temperature region should be provided on the seed crystal growth surface in the early stage of crystal growth, and the single crystal should be grown in the latter half of the single crystal growth with the temperature distribution on the growth surface being substantially uniform. It is characterized by. When a single crystal is grown on a just-angled seed crystal, the single crystal grows from a plurality of growth nuclei, so that a seam of the crystal is generated, which causes the generation of defects. In order to prevent this, it is effective to set the growth plane to an off-angle because a single crystal can be grown by a step flow growth mode. In the present invention, by providing the low-temperature region, the vertical growth of the single crystal in the low-temperature region is increased more than the vertical growth of the single crystal in the periphery, and a substantially off-angle state is formed in the initial stage of the single crystal growth. I do. Thus, step flow growth of the single crystal can be performed at the initial stage of the growth of the single crystal.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Single crystals to which the method of the present invention can be applied are not particularly limited, and the method of the present invention can be used for producing various single crystals composed of a single element or a compound.
Preferred single crystals to which the method of the present invention can be applied include, for example, silicon carbide single crystals. A specific method for providing the low-temperature region includes, for example, the following method. a) A method in which the low-temperature region is realized by a seed crystal receiver structure having at least one counterbore on a surface of the seed crystal receiver opposite to a surface on which the seed crystal substrate is placed. b) A method in which the low-temperature region is realized by a seed crystal mounting part structure in which the surface on which the seed crystal substrate of the seed crystal mounting part is installed is an inclined surface. c) The method wherein the low temperature region is realized by a seed crystal mounting structure having at least one notch on a side surface of the seed crystal mounting. d) A method in which the low-temperature region is realized by a seed crystal receiver structure having at least one portion having poor thermal conductivity on a surface of the seed crystal receiver opposite to a surface on which the seed crystal substrate is placed. e) A method in which the low-temperature region is realized by a seed crystal receiver structure having at least one groove around a surface of the seed crystal receiver on which the seed crystal substrate is placed. f) A method in which the low-temperature region is realized by a combination of the seed crystal mounting structure described in a) to e). In addition to the methods a) to f) described above, for example, a temperature control unit (for example, a metal or ceramic molded body) is disposed at a predetermined position of the seed crystal mounting unit, and the temperature of the temperature control unit is controlled. Various methods may be used, such as providing a low-temperature region in the method of the present invention by heating (heating or cooling).

In the method (a), one or two or more counterbores may be provided. The size, shape, and depth of the counterbore are appropriately selected. The counterbore diameter is preferably 5 mm or less. More preferably, it is less than 2 mm. The depth of the counterbore is preferably such that the tip reaches a position of 1 to 5 mm from the bonding surface between the seed crystal and the grown single crystal. The inclination angle of the inclined surface in the method b) is appropriately selected within a range of 0 to 90 degrees. In the method c), one or more cuts may be provided. The size, shape and depth of the cut are appropriately selected. The width of the cut is preferably 0.1 to 5 mm, and the depth is preferably such that the seed crystal mounting portion is left 1 to 5 mm. The portion having poor thermal conductivity in the method d) is formed at a predetermined portion of the seed crystal mounting portion using a material having lower thermal conductivity than the material forming the seed crystal mounting portion. For example, a predetermined portion of the seed crystal mounting portion is replaced with the above-described material having poor thermal conductivity, or a molded body made of the material having low thermal conductivity is embedded in a predetermined portion of the seed crystal mounting portion. As a material having poor thermal conductivity, it is preferable to use a material having a thermal conductivity of 1 / 1.5 or less of the thermal conductivity of the material forming the seed crystal mounting portion. For materials with poor thermal conductivity, leave the original material that constitutes the seed crystal mounting part at a maximum of 5 mm in the radial direction of the mounting part. It is preferable to arrange so as to leave about 1 to 5 mm of the original material. In the method e), one or more grooves may be provided. Groove size,
The shape and depth are appropriately selected. It is preferable to leave a mounting portion of 5 mm or less between the edge of the seed crystal mounting portion and the groove, and leave a mounting portion of 5 mm or less inside the groove for a low-temperature portion on the mounting portion. Is good. The depth of the groove is preferably 1 mm or less. By appropriately combining the methods a) to e),
It can be adapted to the production of various single crystals.

[0009]

The present invention will be described in more detail with reference to the following examples and comparative examples. Apparatus Used in the Method of the Present Invention FIG. 1 is a schematic configuration diagram of an example of a silicon carbide single crystal manufacturing apparatus that can be used in the method of the present invention. The reaction vessel includes a graphite crucible 1 and a graphite lid 2.
Silicon carbide raw material powder 3 is placed in graphite crucible 1, and silicon carbide raw material powder 3 is placed in graphite lid 2 which also serves as a seed crystal mounting part.
The seed crystal 4 is provided in opposition to the above. In this example, a counterbore 6 for locally lowering the temperature of the seed crystal growth surface was provided on the graphite lid 2. The growth of the seed crystal is performed by adjusting the temperature with a resistance heating element (not shown) made of graphite and adjusting the pressure of an inert gas or the like. Specifically, the raw material temperature: about 220
0 ° C to 2400 ° C, seed crystal temperature: about 2100 ° C to 230
A silicon carbide single crystal 5 is grown at 0 ° C. and an atmospheric pressure of about 1 Torr to several tens Torr. In the following figures, 7 indicates a cut, 8 indicates porous carbon, 9 indicates a groove, and 10 indicates an inclined mounting portion.

Example 1 A 4H polymorphous silicon carbide bulk single crystal was grown by sublimation using the lid (seed crystal mounting portion) shown in FIG. As the seed crystal substrate, a (000 1 ) just face of a 4H polymorphic silicon carbide single crystal having no through-hole defect was used. Diameter 25mm
A counterbore 6 was prepared on the back side (surface opposite to the surface on which the seed crystal substrate is placed) of the lid including the convex portion of the above, so that the diameter was 2 mm and the distance L from the seed crystal bonding surface was 2 mm. A seed crystal was fixed to the lid with a counterbore 6 and placed in the single crystal manufacturing apparatus shown in FIG. 1, and a silicon carbide single crystal was grown under the above conditions using a conventional sublimation process. In this case, counterbore 6
The vicinity where there is is lower in temperature than the peripheral part due to heat radiation. That is, the temperature of the central portion of the seed crystal becomes relatively lower than that of the peripheral portion. This means that the degree of supersaturation of the silicon carbide gas in contact with the central portion of the seed crystal is higher than that in the peripheral portion of the seed crystal. Therefore, it is expected that the nucleation density of the growth nuclei will increase in the central part of the seed crystal. It is also expected that the density of growth steps due to screw dislocations introduced by joining growth steps between growth nuclei will also increase. On the other hand, in the periphery of the seed crystal, a step flow growth mechanism in which the growth is performed by advancing the step in the central portion becomes dominant. Some single crystal ingots obtained by the method of the present invention were cut and polished perpendicular to the growth direction, and the defect density was measured by a molten alkali etching method and an orthogonal polarization microscope. As a result of the measurement, the presence of a through hole defect was not confirmed over the entire surface of the wafer. Next, with respect to the single crystal ingot, the screw dislocation density was compared and examined between the central part and the peripheral part. Screw dislocation density is determined by adding molten alkali (for example,
(KOH: 500 ° C. × 7 minutes) An etch pit was formed by applying an etching method, and the etch pit was measured by observing it with an optical microscope. As a result, the central part: 10 ² to 10 ³ cm
⁻² , peripheral portion: 0 to 10 ² cm ⁻² , and it was presumed that the single crystal was grown mainly by the two-dimensional nucleation mechanism in the central portion and by the step flow mechanism in the peripheral portion. These growth mechanisms are remarkable in the early stage of growth where a temperature difference is likely to occur between the central part and the peripheral part. In the later stage of growth, the thermal conductivity of the silicon carbide single crystal is larger than that of a graphite lid (graphite polycrystal) or the like, so that the temperature difference in the radial direction of the growth surface depends on the growth apparatus (growth crucible side wall, etc.). Since it is strongly constrained by the temperature distribution, it becomes smaller gradually. That is,
It is assumed that the step flow mechanism gradually becomes dominant over the entire growth surface. In order to make the temperature distribution in the growth surface uniform in the latter half of the growth, active and / or
Alternatively, if a passive radiation plate is arranged opposite to the growth surface (not shown), the effect is increased. Since the single crystal ingot thus obtained is formed on one crystal plane, it is suitable for use in uniform doping, and the production yield of the substrate is improved. Therefore, when the method of the present invention is applied to a seed crystal having no through-hole defect, a high-quality single crystal having no through-hole defect can be manufactured with good reproducibility. Although the single crystal obtained by the method of the present invention has a portion (central portion) where the screw dislocation density is relatively high, the effect of the screw dislocation on the device characteristics has not been clarified at present. However, even if it is clear in the future that the device manufactured from the single crystal obtained by the method of the present invention may malfunction, the position of the screw dislocation can be specified in advance, so that the dislocation density can be reduced. By using a low portion (peripheral portion), a high-performance device can be manufactured.

Example 2 Using the same lid (seed crystal mounting part) as in Example 1, a 4H polymorph silicon carbide bulk single crystal was grown by sublimation. As a seed crystal substrate, a (000 1 ) just face (diameter 25 mm) of a 4H polymorphic silicon carbide single crystal having through-hole defects (density: 20 cm ^-2 ) was used. When this lid is used, the growth end face becomes convex (substantially conical) in the initial stage of growth (not shown). The through hole defect has a property of extending in a direction perpendicular to the growth end face, and as the growth proceeds, the through hole defect around the seed crystal is discharged to the outer peripheral portion. As a result of measuring the defect density of the single crystal obtained by the method of the present invention, it was found that the through-hole defect density was reduced to 16 cm ^-2 . Although it depends on the in-plane distribution of the through-hole defects in the seed crystal, the through-hole defects existing in the peripheral portion of the seed crystal can be gradually reduced by using the method of the present invention. Therefore, when the method of the present invention is applied to a seed crystal having through-hole defects, a single crystal having a relatively low through-hole defect density can be manufactured with good reproducibility. In the above description, as the lid for lowering the temperature of the central part of the growth surface, a lid having a counterbore (seed crystal mounting portion) is shown. (See FIG. 3) having at least one portion having poor thermal conductivity formed of a material having poor thermal conductivity such as porous carbon on the surface opposite to the surface on which the seed crystal substrate is provided. (The central part is made of graphite having good thermal conductivity) (FIG. 4), a lid having at least one groove around the mounting surface of the seed crystal mounting part (FIG. 5), or a combination of these as appropriate Even when used, the same effects as in the first and second embodiments can be obtained. The shape and size of the counterbore may be appropriately selected depending on the density and purity of the graphite used and the size of the seed crystal used. Especially diameter 10
As a lid used for manufacturing a wafer having a size of 0 mm or more, a step-shaped counterbore as shown in FIG. 6, a substantially conical counterbore as shown in FIG. 7, and a step-shaped groove as shown in FIG. The use of the cover having the above-mentioned feature can provide a greater effect.

Example 3 Using the lid (seed crystal mounting portion) shown in FIG. 9, a 4H polymorphous silicon carbide bulk single crystal was grown by a sublimation method. As a seed crystal substrate, a (000 1 ) just face (diameter: 25 mm) of a 4H polymorphic silicon carbide single crystal having no through-hole defect was used. A mounting body having an inclined mounting surface having an inclination angle θ of 20 ° from the horizontal plane of the mounting surface was used (FIG. 9). A seed crystal was fixed on the lid having the inclined mounting surface, placed in the single crystal manufacturing apparatus shown in FIG. 1, and a silicon carbide single crystal was grown under the above conditions using a conventional sublimation method. In this case, the temperature of the point A becomes higher than that of the point B due to the heat conduction of the graphite. That is, a temperature drop occurs from the point A to the point B of the seed crystal. By analogy with the first embodiment, it is expected that the growth of the step flow will be dominant from the point B to the point A. The defect density of some single crystal ingots obtained in this example was measured using the same method as in Example 1. As a result of the measurement, the presence of a through hole defect was not confirmed over the entire surface of the wafer. Regarding the screw dislocation density, location A: 0 to 10 ² cm ^-2 , B
Location: 10 ² to 10 ³ cm ^-2 . Therefore, when the method of this embodiment is applied to a seed crystal having no through-hole defect, a high-quality single crystal having no through-hole defect can be manufactured with good reproducibility. Since a location (location B) where the dislocation density is relatively high can be specified in advance in the same manner as in the first embodiment, a high-performance device can be manufactured by using other locations. Note that the inclination angle of the mounting surface is not limited to the angle of the present embodiment, but can be applied by combining the counterbore used in the first embodiment and the structure described in the second embodiment (not shown). , 0 ° <θ <90 °. In the above description, a lid (seed crystal mounting portion) having an inclined mounting surface is shown as a lid for lowering the temperature of one end of the growth surface. Lid with at least one notch in its part (Fig. 10), and at least one thermal conductivity formed of a material with poor thermal conductivity such as porous carbon around the surface opposite to the surface on which the seed crystal substrate is placed A lid having a portion with poor roughness (FIG. 11), a lid having a counterbore around the surface opposite to the surface on which the seed crystal substrate is placed (FIG. 12),
Alternatively, the same effect as that of the present embodiment can be obtained even when these are used in appropriate combination. In addition, diameter 100m
If a lid having a stepped counterbore and an inclined mounting surface as shown in FIG. 13 is used as a lid used for manufacturing a wafer of m or more, the above-mentioned effect can be further enhanced.

In the above embodiment, the case of a 4H polymorphic silicon carbide seed crystal has been described.
Similar effects can be obtained by using polymorphous silicon carbide. Further, in the above-described embodiment, the example in which the surface on which the seed crystal substrate is placed is the one end surface of the protruding portion is described. However, the lid is not limited to this. For example, as shown in FIG. Of course, a lid having such a shape may be used. Further, in the above embodiment, as the single crystal growth apparatus, the apparatus in which the seed crystal is disposed in the upper portion and the raw material is disposed in the lower portion has been described. Applicable. Further, as for the heating method, the same effect can be obtained by using a conventionally known high-frequency induction heating method.

COMPARATIVE EXAMPLE Using the lid (seed crystal mounting portion) shown in FIG.
Polymorphic silicon carbide bulk single crystals were grown. As a seed crystal substrate, a (0001) just face (diameter 25 mm) of a 4H polymorphic silicon carbide single crystal having no through-hole defect was used. As a result of measuring the defect densities of some single crystals obtained in this comparative example, the through-hole defect density was about 10 cm ⁻² , the screw dislocation density was about 10 ⁴ cm ⁻² , and the defects were in-plane. Was unevenly distributed.

In the above embodiment of the present invention, single crystal growth of silicon carbide has been described, but other crystals, for example, Ga
N, ZnSe, ZnS, CdS, CdTe, AlN, B
It can be applied to the production of N and the like.

The growth surface of the seed crystal in the method of the present invention
The definition of the temperature difference between the low-temperature part and the high-temperature part will be described in more detail below, taking silicon carbide as an example, in order to define the temperature difference between the low-temperature part and the high-temperature part on the seed crystal growth surface in the method of the present invention. In the method of the present invention, silicon carbide is grown by sublimating source gas species from the source SiC powder disposed on the high-temperature side and diffusing them onto a seed crystal disposed on the low-temperature side, as in the conventional growth method. And recrystallized. The temperature at each point in the reaction crucible is determined by heat radiation and heat conduction of each material. Among these, the temperature difference between the raw material powder temperature and the seed crystal is one important requirement when producing a high-quality silicon carbide single crystal. The details of the temperature difference in the initial stage of the growth described in the present embodiment are as follows. The following symbols X,
Y, U, and V indicate symbols X, Y, U, and V in FIG. 1) Temperature difference between central part X of seed crystal and central part U of raw material: 2
0-40 ° C, desirably 20-30 ° C 2) Temperature difference between seed crystal peripheral portion Y and raw material peripheral portion V: 0
２０20 ° C., desirably 5 to 15 ° C. 3) Temperature difference between central part X of seed crystal and peripheral part Y of seed crystal:
10 to 40 ° C, preferably 10 to 30 ° C

In this embodiment, in the initial stage of growth, 1 ') the temperature difference between the seed crystal central part X and the raw material central part U:
25 ° C. 2 ′) Temperature difference between seed crystal periphery Y and raw material periphery V:
5 ° C. 3 ′) Temperature difference between seed crystal central part X and seed crystal peripheral part Y: set at 20 ° C., the thermal conductivity of silicon carbide increases with the elapse of growth time, and the inside of the new crucible increases. Temperature control between the seed crystal central portion X and the seed crystal peripheral portion Y so that the temperature difference between the seed crystal central portion X and the raw material central portion U is:
25 ° C. 2 ″) Temperature difference between the seed crystal peripheral part Y and the raw material peripheral part V:
20 ° C. 3 ″) The temperature was controlled so that the temperature difference between the seed crystal central part X and the seed crystal peripheral part Y was 5 ° C. or less, preferably 0 ° C. These temperature differences, especially the seed crystal center Since the temperature difference between the portion X and the raw material central portion U and the temperature difference between the seed crystal peripheral portion Y and the raw material peripheral portion V greatly affect the crystallinity of the single crystal obtained as described above, It is determined according to the quality desired for a specific device, and when growing a crystal for a substrate that does not require a very low defect density, it is necessary to consider manufacturing costs.
A growth program for gradually increasing the temperature difference between the seed crystal and the raw material may be employed.

[0018]

According to the method of the present invention, for example, at least one relatively low temperature region is provided on the growth surface of the seed crystal at the initial stage of the growth of the single crystal by using the seed crystal mounting portion having a specific structure. Therefore, generation of growth nuclei can be controlled in the initial stage of single crystal growth (for example, generation of a plurality of growth nuclei can be suppressed), and a growth mode of a step flow can be realized. The crystallinity of the crystal is dramatically improved. In particular, when the structure of the seed crystal mounting portion in which the temperature of the central portion is relatively lowered is adopted, since the crystal is grown with a substantially conical crystal outer shape in the initial stage of growth, the crystal exists around the seed crystal. Through hole defects are discharged to the outside, and the defect density can be reduced. Further, in the latter half of the growth of the single crystal, the temperature distribution on the growth surface becomes substantially uniform, so that uniform doping becomes possible, and the production yield of the substrate is drastically improved. A seed crystal mounting portion (for example, a lid) used in the method of the present invention can be prepared in various forms relatively easily.
1) Since a just-in-plane substrate can be used, the method of the present invention can be carried out at a low cost, and is also applicable to a process for increasing the diameter of a grown crystal. Therefore, according to the method of the present invention, a large-area single crystal ingot can be manufactured with high quality and high reproducibility. Therefore, when the obtained single crystal is used as a semiconductor material, a high-performance semiconductor device can be manufactured with high yield.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of a silicon carbide single crystal manufacturing apparatus that can be used in the method of the present invention.

FIG. 2 is a cross-sectional view of another example of the lid of the apparatus of FIG.

FIG. 3 is a cross-sectional view of another example of the lid of the apparatus of FIG.

FIG. 4 is a cross-sectional view of another example of the lid of the apparatus of FIG.

5 is a cross-sectional view of another example of the lid of the apparatus of FIG.

FIG. 6 is a sectional view of another example of the lid of the apparatus of FIG. 1;

FIG. 7 is a sectional view of another example of the lid of the apparatus of FIG. 1;

8 is a cross-sectional view of another example of the lid of the device of FIG.

9 is a cross-sectional view of another example of the lid of the device of FIG.

FIG. 10 is a sectional view of another example of the lid of the apparatus of FIG. 1;

11 is a cross-sectional view of another example of the lid of the device of FIG.

FIG. 12 is a sectional view of another example of the lid of the apparatus of FIG. 1;

FIG. 13 is a sectional view of another example of the lid of the apparatus of FIG. 1;

FIG. 14 is a cross-sectional view of a lid according to a comparative example.

FIG. 15 is a diagram for explaining a temperature difference between a low-temperature portion and a high-temperature portion of a seed crystal growth surface in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Graphite crucible 2 Graphite lid 3 Silicon carbide raw material powder 4 Seed crystal 5 Silicon carbide single crystal 6 Counterbore 7 Cut 8 Porous carbon 9 Groove 10 Slant mounting surface

Continuing on the front page (72) Inventor Naohiro Sugiyama 41-Cham Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside of Toyota Central Research Laboratory Co., Ltd. No. 1 Inside Toyota Central Research Laboratories Co., Ltd. (72) Nobuo Kamiya Inventor No. 41 Nagachute-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture 1-1-1 Showacho Inside DENSO Corporation

Claims (1)

[Claims] 1. A method for producing a single crystal by growing a single crystal on a seed crystal substrate placed on a seed crystal mounting portion, wherein at least one of the single crystals grows relatively to a growth surface of the seed crystal at an initial stage of the growth of the single crystal. A method for producing a single crystal, comprising: providing a low temperature region, and growing the single crystal in a state in which the temperature distribution on the growth surface is substantially uniform in the latter half of the single crystal growth.