JPH11171681A - High-temperature member for single crystal pull-up device and production of the member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight member with extended service life, usable in the form of crucible or the like, by partly or wholly including a carbon fiber-reinforced carbonaceous composite material having each specific or higher level bulk density, flexural strength and tensile strength and bearing a pyrolyzed carbon deposition layer on the surface. SOLUTION: This high-temperature member consists partly or wholly of a carbon fiber-reinforced carbonaceous composite material which has a bulk density of >=1.3 g/cm<3> , flexural strength of >=80 MPa, and tensile strength of >=100 MPa; wherein the composite material bears a pyrolyzed carbon deposition layer on part or the whole of the surface which is formed by chemical vapor deposition method, and there are numerous fine recesses attributable to open pores on the surface; the above vapor deposition treatment effectively prevents teaching phenomena due to SiC conversion as a result of contact with SiO gas, or silicon deposition phenomena when this member is used as a crucible or the like. The above composite material is obtained by impregnating carbon fiber with pitch or a resin to form a prepreg which, in turn, is subjected to carbonization treatment followed by graphitization treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member used under a high-temperature atmosphere in a single crystal pulling apparatus using a Czochralski (CZ) method or the like.

[0002]

2. Description of the Related Art The main part of this kind of single crystal pulling apparatus is
As shown in FIG. 1, a quartz crucible (hereinafter simply referred to as "crucible") 1 for melting a semiconductor material such as silicon, a member serving as a crucible 10 for mounting and supporting the quartz crucible 1, and this crucible 1 is constituted by a member serving as a heat shield (not shown in the figure). Heat shield is a general term for members that aim to shield heat, radiate heat, rectify silicon vapor, improve the uniformity of temperature inside the device and improve heat retention,
Mainly inner shield 2, upper ring shield 3,
It comprises a lowering shield 4, a lower shield 5 and an upper shield 6.

[0003] The inner shield 2 has a cylindrical shape surrounding a graphite heater 8 for heating the crucible 1, and the upper ring shield 3 and the lower ring shield 4 are located above and below the inner shield 2, respectively. Are also hollow disk shaped. The lower shield 5 is located below the crucible 1, has a hole at the center thereof through which the crucible support rotation shaft 7 can pass, and generally has a conical cylindrical vertical section. Further, the upper shield 6 includes the crucible 1
, Has an opening in the center thereof through which the silicon single crystal 9 can pass, and has an inverted conical cylindrical shape in longitudinal section. Hereinafter, these members (reference numerals 2, 3, 4, 5, in the figure)
If it is not necessary to distinguish 6) in particular, a typical description will be given using a general term of “heat shield”.

A member used in a single crystal pulling apparatus under a high temperature atmosphere in a single crystal pulling apparatus (hereinafter, abbreviated as a "high temperature member") has conventionally been made of graphite having excellent mechanical strength and heat resistance. High temperature components have been used. When the supporting crucible 10 is made of graphite, a split-type supporting crucible is generally used in order to prevent cracks due to a difference in thermal expansion from the inner quartz crucible 1. For this reason, there is a situation that the production of the crucible and the maintenance of the pulling device tend to be complicated. Recently, single crystal pulling apparatuses have also been increasing in size with the increase in diameter of single crystals, and high-temperature members (2, 3, 4, 5, 5 in the figure) such as the supporting crucible 10 have been used.
6) is a problem. This is because such an increase in weight, coupled with the narrowing of the free space in the apparatus, leads to a sharp decrease in handling performance.

Under these circumstances, a carbon fiber reinforced carbon composite material (hereinafter referred to as “C / C”) that is lightweight, has high strength and heat resistance, and does not change much in thermal expansion difference from the quartz crucible 1.
Material ". ), And the supporting crucible 10 made of C / C material is already known (actual 3-
No. 43250), and the adoption of high-temperature members other than the supporting crucible 10 is being studied because it can be made thinner (lighter) and the economical efficiency of the device can be improved.

[0006]

However, the light weight property which is an advantage of the C / C material is that it is much more porous than graphite in terms of tissue structure. When the material is used as a high-temperature member in a special high-temperature atmosphere in a single crystal pulling apparatus, the damage to the high-temperature member made of the C / C material itself is larger than that of the graphite member, and the life is shortened. It has become clear. That is, during operation of the single crystal pulling apparatus, the vicinity of the upper portion of the supporting crucible 10 is filled with the melted single crystal material 11 and the SiO gas generated from the quartz crucible 1, so that the upper portion of the supporting crucible 10 itself and the upper portion of the molten single crystal material 11 are filled. If a C / C material is used for the heat shield facing the vicinity (mainly 2, 3 and 6 members in the figure), SiO gas enters into many micropores existing on the surface and is exposed. Reacts with the carbon atom C to make SiC easily proceed. As a result, the phenomenon of so-called "cracking" in which the surface layer is chipped is rapidly progressing, and the service life is expended in a short period of time, so that a new hot member must be replaced.

Also, due to the structure of the apparatus, the inner surface of the heat shield (mainly the lower side of the members 4 and 2 in the drawing) is located at a portion where the temperature is relatively low, especially the minute surface of the surface. The silicon vapor is condensed around the pores as a nucleus and easily adheres. And once they adhere,
The solidified silicon gradually accumulates, and the entire or a part of the inner surface of the heat shield is made uneven. The heat shield having such a bumpy (irregularity) state appears as deformed or warped after cooling, so that it cannot be used repeatedly, and its life is eventually exhausted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to take advantage of the inherent advantages (light weight and high strength) of a high-temperature member made of a C / C material while maintaining its advantages. It is an object of the present invention to provide a high-temperature member capable of solving a disadvantage that a "cracking" phenomenon caused by a SiC reaction or a deformation phenomenon after cooling caused by silicon adhesion growth easily occurs.

[0009]

Means for Solving the Problems According to the first aspect of the present invention which has attained the above object, a high temperature member for a single crystal pulling apparatus formed entirely or partially of a C / C material is provided. The C / C material has a bulk density of 1.3 g as a characteristic.
/ cm ³ or more, bending strength 80MPa or more, tensile strength 10
It has a value of 0 MPa or more, and is characterized in that a deposited layer of pyrolytic carbon is formed on the whole or a part of the surface of the C / C material.

[0010] Accordingly, pyrolytic carbon can be efficiently deposited on the inner surface of many small open pores (including deep open pores) existing on the surface of the C / C material high-temperature member. The reaction between C and SiO gas is effectively suppressed over the entire surface of the substrate, and the progress of SiC conversion can be prevented. In addition, as a result of filling the entirety of the micro pits existing on the surface of the high-temperature member with the pyrolytic carbon, the micro pits serving as nuclei where silicon condensation easily occurs can be eliminated, so that the adhesion of silicon can be largely suppressed. Therefore, it is possible to avoid the formation of a remarkable unevenness (irregularity) due to the silicon adhesion layer which has occurred on the inner surface of the conventional graphite high-temperature member, and as a result, deformation and warping after cooling can be prevented. . In addition, since a material having a certain level of mechanical strength is used as the C / C material, it is possible to further reduce the thickness of the high-temperature member while securing the above-described specific operation and effect. This can contribute to further improvement in handling performance.

According to a second aspect of the present invention, in the first aspect of the invention, the C / C material has a characteristic, an elastic modulus of 50 GPa or more, and a Charpy impact strength of 30 kg.
It has a value of not less than cm / cm ² .
As a result, the effect of the invention described in claim 1 can be made more reliable and remarkable.

According to a third aspect of the present invention, in the first or second aspect, the high-temperature member is a crucible. Thus, it is possible to provide a crucible for a single crystal pulling apparatus which is lightweight and has high strength, can prevent formation of SiC, is less likely to be cracked, and has a long life.

According to a fourth aspect of the present invention, in the configuration of the first or second aspect, the high temperature member is a heat shield. This makes it possible to provide a long-life heat shield for a single crystal pulling apparatus which is light in weight and high in strength but can prevent formation of SiC, is less likely to be cracked, and has less deformation and warpage.

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the heat shield is any one of an inner shield, an upper ring shield, a lower ring shield, a lower shield and an upper shield. It is characterized by. This makes it possible to extend the life of at least the main heat shield of the single crystal pulling apparatus and reduce the operating cost of the apparatus.

According to a sixth aspect of the present invention, there is provided the configuration according to any one of the first to fifth aspects of the invention.
The pyrolytic carbon formed on the surface of the high-temperature member is RC
(Rough column), ISO (iso) organization or SC
(Smooth column) It is characterized by having a crystal structure of a structure or a structure combining these structures. The effect of the invention according to any one of claims 1 to 5 is further ensured and remarkable by making it possible to arbitrarily form the pyrolytic carbon into a material having a crystal structure of a structure in which SiC formation hardly proceeds. Things.

[0016] The manufacturing method of the invention according to claim 7 is characterized in that:
Bulk density is 1.3 g / cm ³ or more, bending strength is 80 MPa or more,
A step of forming a deposited layer of pyrolytic carbon by a chemical vapor deposition method on the whole or a part of the surface of a C / C material having a characteristic value of 100 MPa or more in tensile strength. As a result, while utilizing the inherent advantages (points of light weight and high strength) of the C / C high temperature member, the disadvantages of S / C
It is possible to obtain a long-life high-temperature member that can eliminate the tendency of the "cracking" phenomenon caused by the iC conversion reaction or the deformation phenomenon after cooling caused by silicon adhesion growth to occur.

The invention according to claim 8 is the invention according to claim 7, characterized in that the C / C material is a characteristic, the elastic modulus is 50 GPa or more, and the Charpy impact strength is 30 kg.
It has a value of not less than cm / cm ² .
This makes it possible to obtain a high-temperature member having a service life equal to or longer than that of the high-temperature member obtained by the seventh aspect of the present invention.

Further, according to the ninth aspect of the present invention, there is provided the seventh aspect of the present invention.
Alternatively, in the constitution of the invention according to claim 8, the rate of depositing pyrolytic carbon by a chemical vapor deposition method is 0.2 μm / hr or less. Thereby, the higher temperature member than the high temperature member obtained by the invention according to claim 7 or 8 can be used.
It is possible to obtain a high-temperature member capable of exhibiting a more excellent effect in terms of gas reaction suppressing power.

In the above, the C / C material refers to a carbon fiber impregnated with a pitch or a resin, formed into a prepreg, and molded.
It is obtained by performing carbonization treatment and graphitization treatment,
It has the properties of graphite and improved mechanical strength. As a manufacturing method, UD or 2-D starting from pitch-based or PAN-based carbon fiber is used in the production of a molded body.
D is prepreg impregnated with resin, laminated and cured, or 3-D or n-D fabric is impregnated with resin and heated.
A method such as curing is effective.

When the high-temperature member is a crucible, a filament winding (FW) method can be carried out in addition to the above-described method. Can be obtained efficiently. The formed body thus manufactured is carbonized in a non-oxidizing atmosphere to obtain carbonized C / C. Followed by pitch or resin re-impregnation, carbonization or CVD
Densification is performed while repeating the processing. Next, high-temperature heat treatment is performed to obtain graphitized C / C. Finally, a C / C material suitable for a high-temperature member for a single crystal pulling apparatus is obtained by performing a purification treatment (a treatment for removing metal impurities by reacting with a halogen gas).

The C / C material thus obtained is a composite material having carbon fibers therein, and therefore is entirely porous. In particular, the surface has small dents due to open pores and the like. Many exist in a scattered state. When the SiO gas comes into contact with the surface in such a state, it easily reacts with the bare carbon atoms C serving as a matrix to form SiC, that is, “cracking” easily occurs. Condensation of the silicon vapor proceeds with the center of the minute depression as the concentration decreases, and the silicon adhesion layer is easily formed.

Therefore, in order to prevent or delay as far as possible the progress of SiC formation and the formation of a silicon adhesion layer, C
Means for depositing pyrolytic carbon is very effective so as to cover the inner surfaces of a large number of minute open pores existing on the surface of the / C material and to fill the inner surfaces of the minute depressions.

Here, the pyrolytic carbon is a dense, high-purity carbon excellent in gas-liquid impermeability, which is obtained by thermally decomposing hydrocarbons and depositing them from the surface to the inside of the base material. Therefore, this pyrolytic carbon is deposited on the surface of the molded body made of the C / C material, and covers the inner surface of the large number of open pores as described above, so that the SiO gas and the carbon appearing on the surface of the C / C material are covered. By breaking the contact with the atom C and filling a large number of micro-cavities, silicon vapor hardly adheres to the surface of the C / C material, thereby effectively suppressing progress of SiC and formation of a silicon adhesion layer. be able to.

The deposition of the pyrolytic carbon can be carried out only in a portion where SiC formation easily progresses or in a portion where silicon vapor deposition easily progresses. For example, in the case of a crucible, it is possible to deposit only on the inner surface as a whole, or to deposit only at the curved corner portion or only at the curved corner portion and the straight body portion of the inner surface. Speaking of the heat shield, for example, if the inner shield is deposited only on the upper inner surface, or if the lower ring shield or the upper ring shield is deposited only on the inner surface of the ring, a sufficient effect can be exhibited. it can.

It is necessary to pay attention to the thickness of the deposited layer depending on the deposition rate of pyrolytic carbon. That is, if the formed deposit layer is too thick, the C / C material is likely to crack due to the difference in thermal expansion coefficient with the C / C base material, and is likely to be separated from the C / C material. It is. Specifically, in order to avoid the cracks and peeling, the thickness of the deposited layer is 100 μm
The pyrolytic carbon may be deposited so as to be below, more preferably 20 μm or below. However, the thickness of the deposited layer may not be too small. This is because, for example, if the C / C material is exposed only by scratching due to contact during transportation or the like, the effect of suppressing the formation of SiC is lost. From this viewpoint, it is desirable to deposit the pyrolytic carbon so that the thickness becomes at least 1 μm or more.

The C / C material preferably has a bulk density of 1.3 g / cm ³ or more, a bending strength of 80 MPa or more, and a tensile strength of 100 MPa or more. Are more preferably 50 GPa or more and the Charpy impact strength is 30 kgcm / cm ² or more. By using a C / C material having a certain degree of mechanical strength, in addition to the effect of preventing the occurrence of a "cracking" phenomenon caused by the SiC conversion reaction and a deformation phenomenon after cooling caused by silicon adhesion growth. This is because a high-temperature member made of a C / C material can be obtained, which can further reduce the thickness of the device and further improve the handling performance.

Further, in order to deposit pyrolytic carbon on the surface of the C / C material, nitrogen gas or hydrogen gas is usually used for adjusting the concentration of hydrocarbons or hydrocarbon compounds, and the hydrocarbon concentration is 3 to 10%. The reaction operation may be performed at 30%, preferably 5 to 15%, and at a total pressure of 100 Torr or less. When such an operation is performed, the hydrocarbon becomes C / C
From the surface to the inside of the material, a giant carbon compound is formed by dehydrogenation, thermal decomposition, polymerization, etc., which is deposited on the C / C material, further dehydrogenation reaction proceeds, and finally a dense layer of pyrolytic carbon Are formed from the surface to the inside of the C / C material. Generally, the operation of forming a relatively thin “coating layer” on the surface of a substrate is referred to as a “CVD method”, and the operation of forming an “impregnated layer” by depositing a relatively deep portion of the substrate. Although sometimes referred to as “CVI method”, the “precipitated layer” in the present invention is a concept including both the “covering layer” and the “impregnated layer”.

The temperature range for the precipitation is generally between 800 and 2500.
Although it is a wide range up to 100 ° C., it is desirable to carry out the reaction operation in a relatively low temperature range of 1300 ° C. or lower in order to precipitate the C / C material deeply. In order to deposit pyrolytic carbon even on the surface of a large number of minute open pores existing deep in the C / C material, the deposition rate is slowed down.
It is desirable to control it to 2 μm / hr or less.
Further, in order to increase the deposition efficiency of pyrolytic carbon, it is possible to appropriately use operations such as a so-called isothermal method, a temperature gradient method, a pressure gradient method, and a pulse method.

Further, among the forms of the pyrolytic carbon structure, the above-mentioned ISO structure means an optically isotropic structure.
The RC structure refers to a coarse columnar carbon structure, and the SC structure refers to a smooth columnar carbon structure. The deposited layer of pyrolytic carbon is formed so as to have a crystal structure of any one of the above-mentioned ISO structure, RC structure and SC structure, and to have a crystal structure of a structure obtained by combining these structures. However, SiC can be suppressed. In addition, when the precipitation rate is high due to the operating conditions, there is a feature that the SC structure is easily formed, and as the deposition rate is slow, the RC structure and the ISO structure are easily formed. Therefore, in consideration of these points, it is possible to control the structure to be arbitrarily precipitated.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a high temperature member for a single crystal pulling apparatus according to the present invention will be described below with reference to the drawings. (1) FIG. 2 is a longitudinal sectional view of an example of the crucible according to the present invention, and a crucible 21 in which a pyrolytic carbon deposition layer 23a is formed on the entire surface of a crucible body 22 made of a C / C material.
Is shown. The C / C material has a bulk density of 1.3 g / cm ³ in consideration of the mechanical strength required for the crucible and the ease of pyrolytic carbon deposition.
Above, bending strength is more than 80MPa, tensile strength is more than 100MPa
a, a material having a Charpy impact strength of at least 30 kgcm / cm ² and an elastic modulus of at least 50 GPa is used.

The crucible 31 shown in FIG. 3 is a configuration example different from the crucible 21 shown in FIG. 2, and shows an example in which pyrolytic carbon is deposited on a part of the inner surface of the crucible main body 32. That is, in the crucible 31 of FIG. 3, the curved corner portion 32b and the straight body portion 32a are formed of a C / C material, and the bottom portion 32c is formed of a graphite material. 3 shows an example in which pyrolytic carbon is deposited only in the straight body portion 32a. 33a in the figure is a deposited layer of pyrolytic carbon.

The shape of the crucible is generally cup-shaped, as shown in FIGS. 2 and 3. More specifically, with reference to FIG. 2, a bottom 22c and a curved portion are continuously formed on the bottom 22c. While rising upward, that is, the curved portion 22
b and a straight body portion 22a extending straight upward continuously to the curved corner portion 22b.

The crucible body 22 made of a C / C material is manufactured by a filament winding (FW) method, which will be described in a later embodiment, or by a carbon fiber material.
The method can also be carried out by a method of impregnating a resin into the -D cloth and laminating the resin or a method of producing a dispersed C / C using short fibers.

As described above, the pyrolytic carbon is supplied to the crucible main body 2.
In this method, the inner surface of the minute open pores existing on the surface of No. 2 is coated or deposited so as to fill the minute dents. The state of the depositing action will be described in more detail. FIG. 4 shows C /
FIG. 4A is a partially enlarged cross-sectional view of the surface of the C material crucible, and FIG. 4A schematically shows a situation in which a pyrolytic carbon deposition layer 43 is favorably formed on the entire surface of the crucible body 42. FIGS. 7B and 7C schematically show a situation where the formation is not good. In addition, the precipitation layer 43 in FIG.
Means that both the deposited layer 23a in FIG. 2 and the deposited layer 33a in FIG. 3 are included.

On the surface and inside of the crucible body 42, there are minute holes such as open air holes 44 and closed air holes 45.
Among these holes, the open pores 44 form surface depressions (recesses including both deep depressions and shallow depressions).
The surface area of the C / C material is larger than it appears. In particular, as for the open pores (dents) having a narrow entrance and a wide interior as shown in the figure, it is necessary to sufficiently form the pyrolytic carbon deposition layer 43 up to the inner surface of the open pores 44 as shown in FIG. .

When the pyrolytic carbon deposition layer 43 is formed, for example, under conditions where the deposition rate is relatively high, the deposition layer 43 only covers the opening of the open pore 44 as shown in FIG. , Does not spread well into its interior. Since the opening in such a state is unstable in strength and weak, a crack 46 is likely to occur, and an inner portion (a portion where the C / C material is exposed) 44a where the pyrolytic carbon deposition layer is not spread.
May be exposed to the outside in the presence of SiO gas. Also C /
Depending on the C material, the opening of the open air hole 44 may not be closed as shown in FIG.
As in the case of (b), the portion 44 where the C / C material is exposed
a is exposed to the outside in the presence of SiO gas.

Therefore, in order to form a deposited layer of pyrolytic carbon smoothly on the surface of the crucible body 42 where many open pores 44 exist, the deposition rate of pyrolytic carbon should not be too high. It is necessary to sufficiently precipitate the inside of the substrate. From this viewpoint, it is desirable that the deposition rate of the pyrolytic carbon be 0.2 μm / hr or less.

The pyrolytic carbon constituting the deposited layer 43 may have a crystal structure of an ISO structure, an RC structure, an SC structure, or a structure obtained by combining these structures. This is because pyrolytic carbon having any of these texture structures can exhibit the effect of suppressing the formation of SiC. Note that as the deposition rate is reduced in the CVI treatment, the structure of the pyrolytic carbon to be deposited becomes an ISO structure or an RC structure, and precipitates deeper into the C / C material.

(2) FIG. 5 is a longitudinal sectional view showing an example of installation of a heat shield made of a C / C material according to the present invention, and the entire inner surface thereof (the surface in contact with the crucible side space) is shown by oblique lines. Thus, the deposited layer 12 of pyrolytic carbon is formed. C / C
The material has the same characteristics as the crucible described above, that is, a bulk density of 1.3 g / cm ³ or more, a bending strength of 80 MPa or more, a tensile strength of 100 MPa or more, and a Charpy impact strength of 30 or more.
kgcm / cm ² or more and elastic modulus of 50 GPa or more are used. The deposition layer 12 may be formed in the same manner as in the case of the crucible described above, and by this formation, similarly to the operation and effect described in FIG. It will be covered or buried with a deposit. Therefore, as in the case of the crucible, the contact between the SiO gas and the carbon atoms C on the inner surface of the heat shield is cut off, and the SiC
Can be prevented from progressing. Further, since the temperature of the lower side of the inner shield 2 is relatively low, silicon vapor is likely to be condensed in the vicinity of the lower temperature. Effectively avoids condensation and adhesion of silicon vapor,
Can be suppressed.

FIG. 5 shows a state in which the entire cylindrical inner shield 2 is supported as a heat shield on the upper inner peripheral side of the lowering shield 4, and the lower inner peripheral side of the upper ring shield 3 is directly attached to the upper end of the inner shield 2. ,
Further, an example of a structure in which the upper shield 6 is supported at the upper portion on the inner peripheral side of the upper ring shield 3 is shown.

When the inner shield 2, the upper ring shield 3, the lower ring shield 4 and the upper shield 6 are disposed separately as heat shields, the surface of the pyrolysis carbon is basically exposed to the space S. Although a deposited layer may be formed, even in such a case, depending on the amount of SiO gas or silicon vapor generated at the time of pulling a single crystal or the behavior when these flow through the space S centering on the crucible, the SiO gas or silicon vapor The sensitive parts may be relatively limited. In such a case, the object of the present invention can be almost effectively achieved only by providing a pyrolytic carbon deposition layer only on the surface of a portion susceptible to the effect. Further, in consideration of the fact that the upper shield 6 is usually the most susceptible, the present invention is also effective for the upper shield 6 as a matter of course. It is also possible to employ a material in which a SiC coat is applied on a base material such as graphite, for example.

(3) Next, an operation example of the single crystal pulling apparatus incorporating the high temperature member of the present invention will be described with reference to FIG. In FIG. 6, the main part of the single crystal pulling apparatus is
A crucible 61 according to the present invention, a quartz crucible 1 supported inside by the crucible 61, a heater 8 provided to cover the crucible 61 at a position outside the crucible 61 at a fixed distance, and further disposed outside the crucible 61. It consists of a heat shield. The structure of the heat shield is shown in FIG.
The inner shield 2, the upper ring shield 3, the lower ring shield 4, the lower shield 5, and the upper shield 6 are the same. Reference numeral 13 denotes a heat insulating material layer mounted on the outer periphery of the inner shield 2.

When the heater 8 is heated to a high temperature, the crucible 6
The inside of the quartz crucible 1 is heated through 1 and the crystal raw material stored inside the quartz crucible 1 is melted. The crucible 61 is supported on the crucible pedestal 14. The crucible pedestal 14 is rotated by a driving mechanism (not shown) via the rotary shaft 7, and rotates together with the quartz crucible 1 inside the crucible pedestal 14. I do.

The production of a single crystal is performed by heating the heater 8 and growing the crystal raw material in the quartz crucible 1 while rotating the crucible 61 while melting the crystal raw material. In particular, the vicinity of the upper part of the crucible 61, that is, the upper part in the space S has a higher temperature atmosphere than the lower part. Therefore, SiO gas is generated near the upper portion of the crystal raw material 11 melted in the quartz crucible 1. At the same time, the silicon vapor rises and flows in the space S along the heat shield.

However, since the crucible 61 has a pyrolytic carbon deposition layer formed on its surface as described above,
Even when exposed to O gas, contact with carbon atoms C on the surface of the C / C material constituting the crucible body can be effectively blocked, and SiC
Can be prevented from progressing. Further, a deposited layer of pyrolytic carbon is also formed on the inner surface of the heat shield including the inner shield 2, the upper ring shield 3, the lower ring shield 4, the lower shield 5 and the upper shield 6 (in the figure, the deposited layer). 12)
The same effect of suppressing the progress of SiC formation as in the case of a crucible can be exhibited, and the occurrence and progress of silicon condensation and adhesion phenomena in a portion where the temperature tends to be relatively low can be suppressed.

When the production of the single crystal is completed, the heater 8 is turned on.
The heat is over, and the crucible 61 and the quartz crucible 1 are cooled.
You. Heating during the production of a single crystal causes crucible 61 and
The quartz crucible 1 expands based on the respective thermal expansion coefficients.
However, in the cooling process after heating, these
Acupoints shrink. SiO which is a constituent material of the quartz crucible 1 _Two
And the C / C material constituting crucible 61 have a thermal expansion
The difference between the two is small due to the difference in deformation due to expansion and contraction.
The distortion generated between the crucibles is small,
No problem. The crucible 61 has a high mechanical strength.
Since it is composed of C / C material, Si residue during cooling
Sufficient for stress caused by radial and height expansion of crucible
Can withstand.

Although the inner surface of the inner shield 2, the upper ring shield 3, the lower ring shield 4, the lower shield 5 and the upper shield 6, which are heat shields, is hardly formed with a silicon adhesion layer, even if it is formed, it is extremely small. Due to the small amount, these heat shields hardly deform or warp after cooling.

[0048]

EXAMPLES (Examples 1 and 2) First, the outline of the production of a molded body made of a C / C material for forming a crucible body (corresponding to 22 in FIG. 2) will be described. The production was in accordance with the FW method for taking two crucibles. That is, a graphite mold having a spherical shape is attached to both ends of a metal mandrel having an outer shape of 600 mm,
The whole was a capsule-shaped mold. After setting the capsule mold in the FW device, release paper is stuck on the surface, and a 12K roving material of CF (carbon fiber) material is impregnated with phenolic resin (manufactured by Sumitomo Durres) from above. Was done. Regarding the winding angle with respect to the molding die, the parallel winding was performed at an angle of 90 ° with respect to the central axis, and the level winding was performed within a range of 1 to 10 °.

Next, the resin was kept in an oven at 200 ° C. for 10 hours to completely cure the resin. After 2 divides the cured product in the center, with and set in an electric furnace, N ₂ gas stream 100
Firing at 0 ° C. was performed. Next, the operations of pitch impregnation and firing were repeated three times in order to promote the filling and densification of pores generated by firing. After that, a heat treatment (graphitization treatment) at 2000 ° C. was performed, and then a reaction with a halogen gas was performed at 2000 ° C. to perform a high-purity treatment. Thus, a C / C having physical properties of a bulk density of 1.3 g / cm ³ or more, a bending strength of 80 MPa or more, a Charpy impact strength of 30 kgcm / cm ² or more, an elastic modulus of 50 GPa or more, and a tensile strength of 100 MPa or more.
A molded material (crucible) was obtained. However, the physical properties are measured values of a material corresponding to a straight body portion of a crucible.

A test piece of 60 × 10 × 3 (mm) was cut out from the above C / C crucible (material corresponding to a straight body), and
For each of the two of them,
Processing (Example 1) and CVI processing (Example 2)
A deposited layer of pyrolytic carbon was formed on the surface of each test piece.

[CVD treatment] The test piece cut out as described above was placed in a vacuum furnace and heated to 2000 ° C.
While flowing CH ₄ gas at a rate of 5 l / min, the pressure was increased to 5
The specimen was held for 3 hours while controlling to Torr, and a pyrolytic carbon deposition layer having a thickness of 10 μm was formed on the surface of the test piece. [CVI processing] CVI processing was performed in the following manner. That is, another test piece was placed in a vacuum furnace, heated to 1100 ° C., and then controlled to a pressure of 10 Torr while flowing CH ₄ gas at a flow rate of 10 l / min.
Hold for 0 hours. As a coating layer of pyrolytic carbon, only a thickness of 10 μm was formed on the surface of the test piece.
The weight of the test piece after the VI treatment was about three times as large as that of the test piece obtained by the CVD treatment in Example 1, and the weight of the test piece in Example 2 was increased.
As a result, it was confirmed that pyrolytic carbon was deposited deep into the test piece.

(Comparative Example 1) 60 obtained in Examples 1 and 2
A small piece of a C / C material crucible product having a size of × 10 × thickness 3 (mm) was used as a test piece of a conventional C / C material crucible.

Each of the test pieces obtained in Examples 1 and 2 and Comparative Example 1 was subjected to a reaction test with SiO gas. The weight increase rate (%) and SiC conversion rate (%) of the test piece accompanying the reaction with the SiO gas were determined by the following formulas. In the reaction test with the SiO gas, each test piece was set in a vacuum furnace and exposed to an SiO gas atmosphere at a temperature of 1800 ° C. and a pressure of 100 torr for 5 hours.

When the SiO gas comes into contact with the carbon atom C, a reaction represented by the following formula proceeds. SiO + 2C → SiC + CO ↑ Accordingly, if the mass of C, which is the mass before the test, is expressed as W ₁ , and the mass of SiC, which is the mass after the test, is expressed as W ₂ , the weight increase rate (%) is expressed as = (W ₂ / W ₁ −1) × 100, and the SiC conversion rate (%) is determined by converting the molar ratio to the weight% of SiC from the total weight, and the SiC conversion rate = (W ₂ − _{W 1) / ((40/24)} · W 1 -W 1)) × 100 = (3/2) (W 2 / W 1 -1) can be obtained by × 100.

Each of the test pieces obtained above (Examples 1 and 2)
And Comparative Example 1) physical properties and weight gain (%), Si
Table 1 shows the relationship between the C conversion ratio (%) and the results. In Table 2, d1 represents the bulk density (g / cm ³ ) of each test piece before the test, and d2 represents the bulk density (g / cm ³ ) of each test piece after the test. I have.

[0056]

[Table 1]

As is apparent from Table 1, the SiC conversion ratios of Examples 1 and 2 are lower than Comparative Example 1, and the effect of suppressing the formation of SiC by the formation of the pyrolytic carbon deposition layer is obtained. You can see that it is done.

(Embodiments 3 and 4) Next, a test piece of the inner shield according to the present invention was manufactured in the following manner. First, a 6K plain weave (Treca T-300) is used as a carbon fiber woven fabric, so-called CF cloth, and a phenol resin (PR-5 manufactured by Sumitomo Durres) is used for the CF cloth.
[0273] was impregnated, and the amount of resin and volatile matter were adjusted to obtain a prepreg.

Next, this prepreg is 300 × 300
(Mm), 40 sheets were sequentially stacked on a surface plate, a heat-resistant nylon sheet was hung on the top, vacuum-packed, and left in an oven set at 160 ° C for 2 hours while vacuuming. And heat cured. Thus 300x30
A carbon fiber reinforced resin composite material (CFRP) having a size of 0 × thickness 12 (mm) and a bulk density of 1.35 was obtained.

The obtained CFRP was set in an electric furnace,
_The temperature was raised to 800 ° C. at a rate of 10 ° C./h while flowing _two gases to obtain a C / C material. Thereafter, pitch impregnation and firing were repeated three times to perform a densification treatment. Further, as a final heat treatment, heating was performed to 2000 ° C. while flowing N ₂ gas. After performing the graphitization treatment in this way, it is further 2000
High purity treatment is performed by reacting with halogen gas at ℃, finally bulk density 1.6 (g / cm ³ ), bending strength 155MP
a, tensile strength 205 MPa, elastic modulus 105 GPa,
A 2D-C / C material having physical properties of a Charpy impact strength of 45 kgcm / cm ² was obtained. 60 from this 2D-C / C material
A test piece of × 10 × thickness 3 (mm) was cut out, and two of them were subjected to CV in the same manner as the crucible.
D treatment (Example 3) and CVI treatment (Example 4) were performed to form a pyrolytic carbon deposition layer with a thickness of 10 μm on the surface of each test piece.

The physical properties of the obtained test piece for inner shield (Examples 3 and 4) were also examined, and then the SiO 2 test piece (Examples 1 and 2 and Comparative Example 1) was subjected to the same method as the test piece for the crucible described above. A reaction test with a gas was performed to examine a weight increase rate (%) and a SiC conversion rate (%). Table 2 shows the results.

Comparative Example 2 60 obtained in Examples 3 and 4
× 10 × thickness 3 (mm) 2D-C / C material is replaced with conventional C / C
A test specimen of the C inner shield was used, and a reaction test with SiO gas was performed on this specimen in the same manner as in Examples 3 and 4.
The results are also shown in Table 2.

[0063]

[Table 2]

As is clear from Table 2, the SiC conversion rate of the inner shield according to the third embodiment of the present invention is about 74% smaller than that of the second comparative example, and the SiC conversion rate of the fourth embodiment is lower than that of the second comparative example. This is about 77% less than the above, and it can be seen that in any case, the effect of suppressing the formation of SiC is obtained by the formation of the pyrolytic carbon deposition layer. In addition, it can be seen that, when the deposited layer of pyrolytic carbon is formed by the CVI treatment, a more excellent effect of suppressing the formation of SiC can be obtained.

[0065]

As described above, the invention according to claim 1 of the present invention is a high temperature member for a single crystal pulling apparatus formed entirely or partially of a C / C material, C
/ C material has a bulk density of 1.3 g / cm ³ or more, a flexural strength of 80 MPa or more, a tensile strength of 100 MPa or more, and the whole or a part of the surface of the C / C material. In which a deposited layer of pyrolytic carbon was formed.

As a result, pyrolytic carbon can be efficiently deposited on the inner surface of many minute open pores (including deep open pores) existing on the surface of the C / C material high-temperature member. The reaction between C and SiO gas is effectively suppressed over the entire surface of the substrate, and the progress of SiC conversion can be prevented. In addition, as a result of filling the entirety of the micro pits existing on the surface of the high-temperature member with the pyrolytic carbon, the micro pits serving as nuclei where silicon condensation easily occurs can be eliminated, so that the adhesion of silicon can be largely suppressed. Therefore, it is possible to avoid the formation of a remarkable unevenness (irregularity) due to the silicon adhesion layer which has occurred on the inner surface of the conventional graphite high-temperature member, and as a result, deformation and warping after cooling can be prevented. . In addition, since a material having a certain level of mechanical strength is used as the C / C material, it is possible to further reduce the thickness of the high-temperature member while securing the above-described specific operation and effect. This can contribute to further improvement in handling performance.

According to the second aspect of the present invention, the effects of the first aspect of the present invention can be made more reliable and remarkable. Further, according to the third aspect of the present invention, it is possible to provide a crucible for a single crystal pulling apparatus, which is lightweight and has high strength, can prevent SiC formation, is less likely to crack, and has a long life. According to the fourth aspect of the invention, it is possible to provide a heat shield for a single crystal pulling apparatus which is lightweight and has high strength, can prevent SiC formation, is less likely to be cracked, and has less deformation and warpage. it can.

According to the fifth aspect of the present invention, at least the main heat shield of the single crystal pulling apparatus can be prolonged in life, and the operating cost of the apparatus can be reduced. Further, according to the invention of claim 6, the pyrolytic carbon can be arbitrarily formed into a material having a crystal structure of a structure in which SiC conversion is unlikely to proceed, thereby providing any one of claims 1 to 5. The effects of the invention described in (1) can be made more reliable and remarkable.

According to the seventh aspect of the present invention, C /
While taking advantage of the inherent advantages (light weight and high strength) of the high-temperature member made of C material, the disadvantages are the "cracking" phenomenon caused by the SiC reaction or the deformation phenomenon after cooling caused by silicon growth. It is possible to manufacture a long-life high-temperature member that can eliminate the points that easily occur.

According to the eighth aspect of the present invention, it is possible to obtain a high temperature member having a service life equal to or longer than that of the high temperature member obtained by the seventh aspect of the invention. Further, according to the ninth aspect of the present invention, a high-temperature member capable of exhibiting a more excellent effect in terms of the SiO gas reaction suppressing force than the high-temperature member obtained by the seventh or eighth aspect of the invention is manufactured. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of a main part of a typical single crystal pulling apparatus.

FIG. 2 is a longitudinal sectional view of the crucible according to the present invention.

FIG. 3 is a longitudinal sectional view of another crucible according to the present invention.

FIG. 4 is a partially enlarged cross-sectional view of the surface of a crucible made of a C / C material, where (a) shows a state in which a coating layer of pyrolytic carbon has been successfully formed on the surface, and (b) and (c). Indicates that the formation is not good.

FIG. 5 is a schematic cross-sectional view of a main part of a single crystal pulling apparatus provided with a heat shield according to the present invention.

FIG. 6 is a schematic sectional explanatory view showing an operation state of a single crystal pulling apparatus in which a high temperature member according to the present invention is arranged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crucible 2 Inner shield 3 Upper ring shield 4 Lower ring shield 5 Lower shield 6 Upper shield 7 Rotating shaft 8 Heater 9 Silicon single crystal 11 Melt crystal raw material 12, 23a, 33a, 43 Pyrolytic carbon coating layer 13 Heat insulation material layer 14 Crucible cradle 21, 31, 61 Crucible coated with pyrolytic carbon 44 Open pores 45 Closed pores 46 Crack

Claims (9)

[Claims] 1. A high-temperature member for a single crystal pulling device formed entirely or partially of a carbon fiber reinforced carbon composite material, wherein the carbon fiber reinforced carbon composite material has a bulk density of 1.3. g / cm ³ or more, a bending strength of 80 MPa or more, a tensile strength of 100 MPa or more, and a deposited layer of pyrolytic carbon formed on the whole or part of the surface of the carbon fiber reinforced carbon composite material. A high temperature member for a single crystal pulling apparatus, comprising: 2. The carbon fiber reinforced carbon composite material has the following properties:
^{2. The} high temperature member for a single crystal pulling apparatus according to claim 1, wherein the high temperature member has an elastic modulus of 50 GPa or more and a Charpy impact strength of 30 kgcm / cm ² or more. 3. The high temperature member for a single crystal pulling apparatus according to claim 1, wherein the high temperature member is a crucible. 4. The high temperature member for a single crystal pulling apparatus according to claim 1, wherein the high temperature member is a heat shield. 5. The heat shield comprises: an inner shield;
The high temperature member for a single crystal pulling apparatus according to claim 4, which is one of an upper ring shield, a lower ring shield, a lower shield and an upper shield. 6. The pyrolytic carbon deposition layer formed on the surface of the high temperature member has a crystal structure of RC (rough column), ISO (iso) structure, SC (smooth column) structure, or a structure combining these. The high temperature member for a single crystal pulling apparatus according to any one of claims 1 to 5, which is a material. 7. A carbon fiber-reinforced carbon composite material having a bulk density of 1.3 g / cm ³ or more, a bending strength of 80 MPa or more, and a tensile strength of 100 MPa or more, is chemically or chemically coated on the whole or a part of the surface thereof. A method for producing a high-temperature member for a single crystal pulling apparatus, comprising a step of forming a deposited layer of pyrolytic carbon by a vapor deposition method. 8. The carbon fiber reinforced carbon composite material has the following properties:
Further modulus above 50 GPa, the method for producing a single crystal pulling apparatus for a high temperature member according to claim 7 Charpy impact strength and has a 30kgcm / cm ² or more. 9. The method for producing a high-temperature member for a single crystal pulling apparatus according to claim 7, wherein the rate of depositing pyrolytic carbon by chemical vapor deposition is 0.2 μm / hr or less.