JP2001048693A - Glassy carbon crucible having inner face being polygonal form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the loss in a single crystal raw material and to improve workability and yield at the time of cutting work by using a crucible made of glassy carbon and having the inner face being a polygonal form. SOLUTION: As the glassy carbon, hard and amorphous carbon, which exhibits a black glassy appearance and shows bright shell-shaped fracture, is used. The glassy carbon is generally obtained by carbonizing a cured material of a thermosetting resin. As the thermosetting resin, a phenol resin, an epoxy resin, an unsaturated polyester resin, or the like, is cited. The form of the inner face of a crucible is one of the polygonal forms. Though a triangle form, a square form, a pentagonal form, a hexagonal form, or the like,, is cited, a form close to the objective single crystal is preferably adopted. The preferable length of one side of the inner face of a part forming a cave is 1 to 300 mm from the viewpoint of processability, or the like. The preferable crucible has the inner face having the arithmetic mean roughness (Ra), based on the JIS B0601, of not more than 5 μm, which surface roughness is measured at least at four positions. Thereby, a good single crystal can be grown.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crucible made of glass with a square internal glass surface. In particular, the present invention relates to a crucible made of an internal square glassy carbon suitable for growing a single crystal.

[0002]

2. Description of the Related Art Glassy carbon is a carbon material generally obtained by carbonizing and curing a thermosetting resin, and has a very homogeneous and dense glassy structure. This material has excellent characteristics such as conductivity, chemical stability, heat resistance, high purity, and the like, which are the characteristics of general carbon materials, as well as impermeability, in which constituent particles do not fall off. For this reason, glassy carbon is considered to be suitable for a container for a melt at a high temperature, especially for a crucible for growing a single crystal.

[0003] Containers used for growing single crystals include:
There are boat-shaped or crucible-shaped containers, of which the crucible-shaped containers are generally used. Since the crucible generally has a cylindrical shape, the grown single crystal has a columnar shape. However, the product shape of the single crystal is often a square shape (a rectangular parallelepiped). When the required single crystal has a square shape, it is necessary to cut (cut) the single crystal from a cylindrical shape into a square shape. Therefore, the cutting margin is large, and the wasteful portion increases.

[0004] The cutting of a single crystal is performed in a state where a columnar single crystal is in a crucible or in a state where the single crystal is removed from the crucible. When cutting in a crucible,
It is good when the single crystal is fixed to the crucible, but when the single crystal is not fixed or detached, the single crystal rotates in the crucible and good cutting cannot be performed. In the worst case, the single crystal may be broken. On the other hand, also in the case of cutting in a state where it is detached from the crucible, it is difficult to fix the columnar single crystal, and it is easy to come off. When the fixing is released, the single crystal may be broken.

When a cylindrical glassy carbon crucible is manufactured by a conventionally known method, (1) a method in which a thermosetting resin cured product is machined into a crucible shape and carbonized and fired;
(2) A method in which glass-like carbon obtained by carbonizing and firing a cured thermosetting resin is used as a material and machined using a diamond tool or the like to form a crucible, (3) Thermosetting resin as a raw material Is molded into a crucible shape by pouring into a molding die, and then cured and carbonized. (4) A thermosetting resin is formed into a crucible shape by a method such as hot press molding or injection molding. A method of carbonizing and firing may be considered.
However, when a cylindrical crucible is manufactured by these methods, it is difficult to cope with a small-diameter and long-sized crucible.

[0006]

According to the first, second and third aspects of the present invention, waste of single crystal raw material is reduced, workability and yield during cutting are improved, and a good single crystal is grown. It is an object to provide a glass crucible made of rectangular glass having an inner surface capable of being used.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a crucible made of glass-like carbon having an inner surface having a rectangular inner surface.
In addition, the present invention relates to the above-mentioned crucible made of rectangular glass-like carbon having an inner surface having at least an inner surface of a crystal growing portion having a square shape. Further, according to the present invention, the size of one side of the inner surface is 1 to 300.
mm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The glassy carbon referred to in the present invention is
It is a generally known, hard, amorphous carbon that has a black glass appearance and a brilliant shell-like appearance. Vitreous carbon is generally obtained by carbonizing and firing a cured thermosetting resin. The thermosetting resin used is not particularly limited, and examples thereof include a phenol resin, an epoxy resin, an unsaturated polyester resin, a furan resin, a melamine resin, an alkyd resin, and a xylene resin. Further, a mixture of these resins may be used, and a curing catalyst for the resin is used as needed.

There is no particular limitation on the method for producing the inner-surface rectangular glassy carbon crucible of the present invention, but in order to obtain such a crucible, a square-shaped hollow portion, a so-called square hole, is formed at the center (inner surface). When the square hole is formed by machining, the square hole is processed at the stage of the thermosetting resin cured product in the course of manufacturing. Although a square hole may be machined by using machining or the like on a rod-like cured thermosetting resin, if the shape is thin and long, a long tool is required and machining becomes difficult. Therefore, first, a flat plate of a cured thermosetting resin is processed into a square hole in a shape obtained by dividing the final crucible shape into two, and then these are adhered and integrated to easily integrate. It is preferred. Hereinafter, a method for producing the crucible made of the glass prismatic carbon having an inner surface square will be described in detail.

The thermosetting resin used as a raw material of the cured thermosetting resin may be any of powdery and liquid thermosetting resins, and is not particularly limited. As the thermosetting resin used for bonding, it is preferable to use a liquid or paste thermosetting resin from the viewpoint of easy handling. When a powdery thermosetting resin is used, it is used after being made into a powdery or paste form by a method such as dissolution in an organic solvent. Further, it is preferable to use the same type of thermosetting resin to be used for bonding and the same type of thermosetting resin to be used for bonding, from the viewpoint of preventing cracking and peeling due to a difference in shrinkage during firing. From these viewpoints, preferred examples of the thermosetting resin include a furan resin, a resol-type phenol resin, and a mixed resin thereof.

The above-mentioned thermosetting resin can be molded by various molding methods in order to obtain a desired crucible made of glass-like carbon having a rectangular inner surface. As for the shape of the crucible, the shape of the outer surface (outer periphery) is not particularly limited as long as the inner surface has a square shape. In the present invention, the square is triangular, quadrangular, pentagonal, and the like, but polygonal ones are mentioned. It is preferable to make the shape close to the required single crystal. Further, from the viewpoint of workability of the square hole, the shape is preferably from a square shape to a hexagonal shape. The corner of the square hole may be a corner, but from the viewpoint of crack prevention, chipping prevention, workability, etc., R (R) of 0.2 mm or more.
Is preferably provided.

The method for molding the thermosetting resin is not particularly limited. For example, (1) molding into a rod by casting, (2) molding into a flat plate by casting, and (3) centrifugal molding. For example, there is a method in which the material is once formed into a cylindrical shape, cut at one place in the vertical direction, and then unfolded into a flat plate shape. In particular, in the present invention, it is preferable that the inner surface is formed in a flat plate shape as described in (2) and (3) from the viewpoint of workability for forming a square shape. In addition, since glassy carbon greatly shrinks during carbonization and firing, it is preferable to manufacture a molded body with a size that allows for this shrinkage.

After molding into a required shape by the above method, 5
Heat treatment is performed at 0 to 150 ° C. to sufficiently advance the curing of the thermosetting resin. In addition, at the stage of the thermosetting resin molded product in the rubber state, in order to easily remove volatile components contained in the resin, rough processing such as making a preliminary hole or forming a preliminary groove is performed, and the thickness is reduced. Is preferred. At the stage where the heat treatment at 50 to 150 ° C. has been completed, using NC machining or the like,
Machine processing is performed with dimensions in consideration of the shrinkage ratio during firing to obtain a thermosetting resin cured product having a crucible shape or a divided crucible shape. At this time, a raw material reservoir for storing a single crystal raw material may be provided on the opening side of the crucible.

In the processing of a crucible that is not divided,
If the size of the hollow part (square hole) is small and the depth of the hollow part is deep, it is difficult to insert a tool (knife) to the tip of the hollow part. Because the diameter of the tool (knife) is thin and long,
The tool (blade) shakes and vibrates, and it becomes impossible to perform sound machining. In the case of a crucible for growing a single crystal, if the inner surface of the crucible has a rough surface, the crystal grows from the roughened portion and a good single crystal cannot be obtained. Therefore, in such a case, it is preferable to process the crucible in a divided shape.

In the present invention, it is preferable to prepare a thermosetting resin cured product in which a crucible is divided in advance, and then bond it using a liquid or paste thermosetting resin. After the bonding, heat treatment at 50 to 150 ° C. is preferably performed again to cure the resin in the bonded portion. After the heat treatment of the bonded portion, it is preferable to further perform a heat treatment at a maximum temperature of 150 to 300 ° C. to promote the entire curing. here,
Insufficient curing of the thermosetting resin causes defects in the structure during firing, and if it is severe, foaming and cracking occur, making it impossible to obtain sound glassy carbon.

The method of dividing the crucible is not particularly limited, but may be divided into two to five in the longitudinal direction of the crucible or two in the direction parallel to the longitudinal direction of the crucible as shown in FIG. It is preferable to divide the crucible into two parts, that is, to divide the crucible vertically, from the viewpoint of easiness of processing and simplicity of bonding. The division may be performed in both directions parallel and perpendicular to the length direction of the crucible.

The structure of the bonding portion is not particularly limited. For example, a structure in which planes are simply joined to each other, FIG.
As shown in FIGS. 3A and 3B, a fitting structure in which the fitting portions 3 are formed and the fitting portions 3 are fitted to each other is shown in FIGS.
As shown in (1), a screwing structure in which the screwing portion 4 is formed and screwed into an opposing member is exemplified. Note that, in the present invention, it is preferable to adopt a fitting structure from the viewpoint of securing a large bonding area, preventing bonding strength and preventing displacement during bonding.

The cured thermosetting resin in the form of a crucible adhered, cured and integrated by the above method is placed in an inert atmosphere (usually, an inert gas such as helium, argon or the like, nitrogen, hydrogen, halogen gas or the like). An oxygen-free atmosphere composed of at least one non-oxidizing gas, under reduced pressure or vacuum,
Temperature of about 900 ° C. or more, preferably 1 ° C. in an atmosphere in which the atmosphere is blocked by being buried in graphite powder, carbon powder, or the like.
Carbonization and firing at a temperature of 000 ° C or higher. Thereafter, a high-temperature heat treatment is preferably performed at 1300 ° C. to 3000 ° C. to obtain a crucible made of square glass vitreous carbon on the inner surface.

It is preferable to use a jig for preventing deformation in order to prevent the resulting crucible from being deformed during carbonization firing and high-temperature heat treatment. The material of the jig is not particularly limited as long as it is not deformed or deteriorated at each processing temperature.However, in view of workability, coefficient of thermal expansion, prevention of impurity contamination, etc.
Desirably, a graphite material containing 100 ppm or less of impurities is used.

In addition, the crucible made of an inner rectangular glassy carbon according to the present invention has a JIS measured at least at four or more locations.
The arithmetic average roughness (Ra) specified in B0601 is 5 μm.
m, preferably 3 μm or less, more preferably 1 μm or less. If it is coarser than 5 μm, the crystal grows from a portion having a rough surface, and there is a tendency that a good single crystal cannot be obtained.

The definition of the arithmetic average roughness (Ra) is defined by JI
The cut-off value and the standard value of the evaluation length obtained by the method defined in SB0601 and corresponding to the range of the arithmetic average roughness (Ra) are described in JIS B060.
As shown in Table 1 of FIG. 1, the arithmetic average roughness (Ra) was 2
In the case of exceeding μm, a standard value of a cutoff value of 2.5 mm and an evaluation length of 12.5 mm is used, and an arithmetic average roughness (Ra)
Is 2 μm or less, it is measured using a standard value having a cutoff value of 0.8 mm and an evaluation length of 4 mm.

It is generally preferable to measure the surface roughness in the length direction of the crucible. However, if there is directionality in the surface roughness depending on the processing method and processing direction of the crucible inner surface,
It is preferable to measure in a direction orthogonal to that direction. In addition, it is preferable to determine the measurement site so that at least four or more measurement points can represent the state of the entire surface. In particular, it is preferable to select and measure a plurality of crucibles having deep holes at equal intervals in the depth direction of the holes.

There are no particular restrictions on the size of the inner-surface rectangular glassy carbon crucible according to the present invention, that is, the overall length, wall thickness, dimensions of the inner surface of the hollow portion, and so-called square hole inner surfaces. The total length is preferably 1000 mm or less, more preferably 800 mm or less, and even more preferably 100 to 500 mm, from the viewpoint of preventing deformation during heat treatment.
In addition, the thickness is set at 0.2 from the viewpoint of curing of resin, workability, and the like.
The range is preferably from 10 to 10 mm, more preferably from 0.5 to 7 mm, even more preferably from 1 to 4 mm. further,
The dimension of one side of the inner surface of the portion to be a cavity, that is, the size of one side of the inner surface of a so-called square hole, is preferably in the range of 1 to 300 mm, more preferably in the range of 2 to 200 mm, and more preferably in the range of 3 to 1
A range of 00 is more preferred.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Example 1 Furan resin precondensate (trade name V, manufactured by Hitachi Chemical Co., Ltd.)
F-302) 1.0 part by weight of a curing agent consisting of 30 parts by weight of paratoluenesulfonic acid and 70 parts by weight of ethylene glycol was added to 100 parts by weight, and after sufficiently mixing, the mixture was degassed under vacuum and centrifuged. A cylindrical molded body in a rubber state was molded at a temperature of 40 ° C. with a machine. This cylindrical molded body is cut at one place in the vertical direction, and it is developed to have a length of 400 mm.
A flat molded body having a width of 160 mm and a thickness of 8 mm was obtained.
This molded body was divided into four parts each having a width of 40 mm in the rubber state.

Thereafter, they are kept at 40 ° C. for 5 days at 60 ° C.
For 10 days and at 100 ° C. for 5 days to obtain a flat resin cured product. Next, each of the plate-shaped resin cured products is processed by NC machining to a required size in consideration of the shrinkage rate in firing and high-temperature treatment, and the crucible is vertically divided as shown in FIGS. (Resin direction) was obtained.

Next, two of the above resin cured products are used, and they are opposed to each other so as to form a pot as shown in FIG.
Furan resin initial condensate (trade name V, manufactured by Hitachi Chemical Co., Ltd.)
F-302) A curing agent consisting of 30 parts by weight of paratoluenesulfonic acid and 70 parts by weight of ethylene glycol was added to 100 parts by weight, and a well-mixed mixture was used as an adhesive for bonding. As shown in FIG. 2, the bonding portion was a fitting structure in which the fitting portions 3 were fitted together, and the corner of the square hole 2 was processed to have a radius of 0.2 mm when completed. After the bonding, in order to cure the resin at the bonding portion, two days at 40 ° C., three days at 60 ° C., and one day at 100 ° C.
Daily heat treatment was performed. Further, heat treatment was performed at 150 ° C. for 2 days to obtain a cured resin having a square inner and outer surfaces.

A jig made of graphite material for preventing deformation is installed on the resin cured product having a square inner and outer surface obtained above, placed in an electric furnace, and heated to 1000 ° C. in a nitrogen stream at a rate of 2 ° C./hour. The temperature was raised at a rate, and the temperature was kept at 1000 ° C. for 2 hours to perform carbonization and firing. Thereafter, the temperature is raised to 2000 ° C. at a rate of 10 ° C./hour in an inert atmosphere using a high-purity deformation-preventing jig, and maintained at a temperature of 2000 ° C. for 3 hours. The outer side dimension is 10mm, the inner side dimension is 4mm, the total length is 250mm and the square hole depth is 247mm
A glass-like carbon crucible having a square inner and outer surfaces was obtained.

In the same manner, a total of four glass-like carbon crucibles each having a square inner and outer surface were manufactured. To check the soundness of the obtained glassy carbon crucible, acetone was poured into all four crucibles and leakage was confirmed. No liquid leakage was observed from the bonded parts and the bonded parts were completely integrated. Has been confirmed. In addition, one of the crucibles was cut in the length direction and the surface condition of the inner surface was confirmed. As a result, no roughening was observed and the surface was uniform. Further, the inner surface roughness was measured at substantially equal intervals in the length direction using a surface roughness shape measuring device manufactured by Tokyo Seimitsu Co., Ltd., trade name Surfcom 500B.
As a result of the measurement at each location, the arithmetic average roughness (Ra) was 0.38 μm or less in each case. In this case, the cutoff value was 0.8 mm and the evaluation length was 4 mm.

A single crystal was grown using the remaining three crucibles. Next, the grown single crystal was fixed together with the crucible with wax for bonding, and a 3.5 × 3.5 mm square and 10 mm long rectangular solid single crystal was cut out using a diamond cutter. It was a good single crystal. The weight of the cut single crystal was 77% of the weight of the grown single crystal.

Example 2 A resol type phenolic resin (trade name: VP-13N, manufactured by Hitachi Chemical Co., Ltd.) was degassed in a vacuum and poured into a tray. A 6 mm flat molded product was obtained. Further, this molded body was divided into four parts having a width of 30 mm.

Thereafter, the flat molded product was sandwiched between graphite plates, and was placed at 40 ° C. for 6 days, at 70 ° C. for 5 days, and at 100 ° C.
Heat treatment was performed at 4 ° C. for 4 days to proceed the curing to obtain a plate-shaped cured resin. Next, each of the plate-shaped resin cured products is set to a required size in consideration of the shrinkage rate in firing and high-temperature treatment.
As shown in FIG. 1, the resin cured product 1 was processed by machining, and the crucible was vertically divided (lengthwise) into two parts.

Next, two resin cured products were used, faced each other in a crucible shape, and bonded using the resole type phenol resin as an adhesive. The bonding portion had a fitting structure in which the fitting portions 3 were fitted together as shown in FIG. 2, and the corner of the square hole 2 was processed to have a radius of 0.2 mm when completed. After bonding,
In order to cure the resin of the bonding part, sandwich it between graphite jigs,
Heat treatment was performed at 40 ° C. for 2 days, at 60 ° C. for 3 days, and at 100 ° C. for 1 day. Further, heat treatment was performed at 150 ° C. for 2 days to obtain a cured resin having a square inner and outer surfaces.

A jig for preventing deformation made of a graphite material was installed on the resin cured product having a square inner and outer surface obtained above, and carbonization firing and high temperature treatment were performed under the same conditions as in Example 1. The dimension of one side of the outer surface is 7mm, the dimension of one side of the inner surface is 3mm, and the total length is 1.
A total of four glass-like carbon crucibles having a square shape with a 50 mm and a square hole with a depth of 148 mm were obtained. To check the soundness of the obtained glassy carbon crucible, acetone was poured into all four crucibles and leakage was confirmed. No liquid leakage was observed from the bonded parts and the bonded parts were completely integrated. Has been confirmed.

When one of the crucibles was cut in the longitudinal direction and the surface condition of the inner surface was confirmed, no roughening was observed and the surface was uniform. Furthermore, the surface roughness of the inner surface was measured at substantially equal intervals at four points in the length direction using the measuring device used in Example 1, and the arithmetic average roughness (Ra) was 0.1 in each case.
It was 40 μm or less. In this case, the cutoff value was 0.8 mm and the evaluation length was 4 mm.

A single crystal was grown using the remaining three crucibles. Next, the grown single crystal was fixed together with the crucible with wax for bonding, and a rectangular single crystal of 2.5 × 2.5 mm square and 8 mm in length was cut out using a diamond cutter. It was a good single crystal. The weight of the cut single crystal was 70% of the weight of the grown single crystal.

COMPARATIVE EXAMPLE 1 The same furan resin precondensate and curing agent as in Example 1 were blended in the same amounts as in Example 1, mixed well, and the mixture was vacuum degassed and cast into a pipe-shaped mold. And cured at 40 ° C. to obtain a molded body having a diameter of 15 mm and a length of 150 mm. Next, the above-mentioned molded body was heated at 40 ° C. for 5 days, at 60 ° C. for 10 days, and
Heat treatment was performed at 00 ° C. for 5 days to obtain a cured resin material in the form of a rod. Next, the bar-shaped resin cured product was processed using a lathe to a required dimension in consideration of the shrinkage rate in firing and high-temperature treatment.
Further, heat treatment was performed at 150 ° C. for 2 days to obtain a cured resin having a cylindrical shape. In the same manner, a total of four cured resin products having a cylindrical shape were obtained.

Under the same conditions as in Example 1, the obtained cylindrical resin cured product was subjected to carbonization and high-temperature treatment to obtain an outer diameter of 10 mm, an inner diameter of 5.3 mm, a total length of 102 mm, and A total of four cylindrical glassy carbon crucibles having a depth of 100 mm were obtained. To check the soundness of the crucible,
When acetone was poured into all four crucibles and leakage was confirmed, no liquid leakage was observed.

One of the crucibles was cut in the length direction, and the surface roughness of the inner surface was measured at substantially equal intervals in the length direction by the measuring machine used in Example 1. The arithmetic average roughness (Ra) was 0.38 μm, 0.45
μm, 0.93 μm and 1.98 μm. In this case, the cutoff value was 0.8 mm and the evaluation length was 4 mm.

A single crystal was grown using the remaining three crucibles. Next, the grown single crystal was fixed together with the crucible with wax for bonding, and a 3.5 × 3.5 mm square, 10 mm long rectangular single crystal was cut out using a diamond cutter. As for the crucible of the book, the crystal rotated in the crucible, and the crystal was broken. In the remaining two crucibles, a good single crystal was obtained, but the weight of the single crystal cut out of both was 56% of the weight of the grown single crystal.

Comparative Example 2 The same resol-type phenol resin as in Example 2 was degassed in vacuum and cast on a tray to obtain a flat molded body having a length of 250 mm, a width of 50 mm and a thickness of 11 mm. Was. After sandwiching the plate-shaped molded product between graphite plates, the molded product was heated at 40 ° C. for 6 days for 70 days.
Heat treatment was performed at 5 ° C. for 5 days and at 100 ° C. for 4 days to proceed with curing to obtain a plate-shaped cured resin. This flat resin cured product was divided into 4 parts by machine processing into a width of 12.5 mm, and further processed into a cylindrical shape by using a lathe to a required size in consideration of the shrinkage rate in firing and high-temperature treatment. Next, heat treatment was performed at 150 ° C. for 2 days to obtain a cured resin having a cylindrical shape. In the same manner, a total of four cylindrical resin cured products were produced.

Under the same conditions as in Example 1, the cylindrical resin cured product obtained above was subjected to carbonization firing and high-temperature treatment to obtain an outer diameter of 7 mm, an inner diameter of 4 mm, a total length of 150 mm, and a hole depth of Of the glass-like carbon crucible having a total of 148.5 mm. To confirm the crucible's soundness,
When acetone was poured into all the crucibles to check for leakage, no liquid leakage was observed.

A single crystal was grown using two of the four crucibles. Next, the single crystal thus grown was fixed together with the crucible with wax for bonding, and a single crystal was cut out using a diamond cutter. As a result, the cut out crystal was polycrystalline and was not single-crystallized. Then, when the remaining two crucibles were cut (vertically divided) in the length direction, the one-third point from the tip of the crucible could be clearly identified by visual inspection, which is thought to be due to vibration during lathe processing. There was surface roughness (unevenness).

[0043]

According to the first, second and third aspects of the present invention, the crucible made of glass having an inner surface rectangular shape reduces waste of single crystal raw material, improves workability and yield during cutting, and grows a good single crystal. This is a crucible made of glass-like carbon having an inner surface square shape, which is industrially suitable.

[Brief description of the drawings]

FIG. 1 shows a resin cured product in which a crucible made of an internal square glassy carbon used in an embodiment of the present invention is vertically divided into two parts.

FIG. 2 is a plan view showing a structure in which an adhesive portion of a thermosetting resin cured product having a divided shape is fitted.

FIG. 3A is a plan view in which an adhesive portion of a thermosetting resin cured product having a divided shape is screwed, and FIG. 3B is a partial side view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin hardened material 2 Square hole 3 Fitting part 4 Screw part

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Takayuki Suzuki, Inventor 3-3-1 Ayukawacho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Chemical Co., Ltd. Yamazaki Office (72) Inventor Ryuichi Ouchi Sudacho, Mizuho-ku, Nagoya-shi, Aichi Prefecture No.2 56 Nihon Insulators Co., Ltd. F-term (reference) 4G032 AA07 BA00 GA12 4G077 AA02 BA04 CF00 EG02 NC03 PD02

Claims (3)

[Claims] 1. A crucible made of glass-like carbon having an inner surface having a square inner surface. 2. The crucible according to claim 1, wherein at least the inner surface of the crystal growing portion has a rectangular shape. 3. The crucible according to claim 1, wherein one side of the inner surface has a dimension of 1 to 300 mm.