JP3468080B2 - Method of processing silicon seed crystal and method of manufacturing silicon seed crystal and silicon single crystal - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for treating a seed crystal used for growing a silicon single crystal by the Czochralski method (CZ method), a treated silicon seed crystal, and this silicon seed crystal. The present invention relates to a method for producing a silicon single crystal in which a silicon single crystal ingot is grown.

[0002]

2. Description of the Related Art Conventionally, in the production of a silicon single crystal by the CZ method, a silicon single crystal is used as a seed crystal, which is brought into contact with a silicon melt and then slowly pulled up while being rotated to obtain a single crystal rod. Is growing. At this time, after bringing the silicon seed crystal into contact with the silicon melt,
In order to eliminate dislocations propagating from slip dislocations generated at high density in the silicon seed crystal due to thermal shock, the diameter is set to 3
A so-called seed drawing (necking) is performed in which the diameter is once thinned to form a narrowed portion, and then the crystal diameter is increased to a desired diameter to pull up a dislocation-free silicon single crystal. Such seed stop is Dash Necking
It is widely known as a method and is a common sense when pulling a single crystal ingot by the CZ method.

That is, the shape of a silicon seed crystal that has been used conventionally is, for example, a diameter or about 8 to 20 mm on each side.
The columnar or prismatic silicon single crystal is provided with a notch for setting in the seed holder, and the lower tip shape that first contacts the silicon melt is a flat surface. In order to withstand the weight of a single crystal rod having a high weight and to pull it up safely, it is difficult to make the thickness of the seed crystal smaller than the above in view of the strength of the material.

In the silicon seed crystal having such a shape, since the heat capacity of the tip contacting with the silicon melt is large, a rapid temperature difference occurs in the crystal at the moment when the silicon seed crystal comes into contact with the silicon melt, and a slip occurs. Dislocations are generated at high density. Therefore, the necking is required to erase the dislocations and grow a silicon single crystal.

However, in such a state, even if various necking conditions are selected, it is necessary to narrow the minimum diameter to about 3 to 5 mm in order to eliminate dislocations. Due to the increase in diameter, the strength is insufficient to support the heavy-weight single crystal rod, and during pulling up of the single crystal rod, this narrow drawing part breaks and the single crystal rod falls, causing a serious accident. There was a risk of.

In order to solve such a problem, the applicant of the present invention has previously disclosed Japanese Patent Laid-Open Nos. 5-139880 and 9-2.
An invention such as Japanese Patent No. 55485 has been proposed. These inventions compare the diameters of the narrowed portions by making the shape of the tip of the silicon seed crystal into a wedge shape or a shape having a hollow portion, and reducing the slip dislocation entering when the silicon seed crystal comes into contact with the silicon melt as much as possible. Even if the thickness is made thicker, dislocation-free can be achieved, thereby improving the strength of the narrowed portion.

According to this method, since the thickness of the throttle portion can be increased, the strength of the throttle portion can be improved to some extent, but necking is performed to form a throttle portion having slip dislocations. In recent years, the strength has sometimes become insufficient for pulling a single crystal ingot having a larger diameter and a longer length, for example, more than 150 kg, and a fundamental solution has not been reached yet.

Therefore, the present applicant has previously developed and proposed a method of making a crystal into a single crystal without forming a narrowed portion due to necking, which is the most problematic in terms of strength (Japanese Patent Application No. 9-1).
7687). In this method, the tip of the silicon seed crystal to be brought into contact with the silicon melt has a pointed shape, or the pointed tip is cut off.First, the tip of the silicon seed crystal is gently contacted with the silicon melt. After that, the silicon seed crystal is lowered at a low speed to melt until the tip portion of the silicon seed crystal has a desired thickness, and then the silicon seed crystal is slowly raised to a desired diameter without necking. This is to grow a silicon single crystal.

According to this method, when the tip of the silicon seed crystal is first brought into contact with the silicon melt, the contact area is small and the heat capacity of the tip is small, so that the silicon seed crystal is subjected to thermal shock or a rapid temperature gradient. Therefore, slip dislocations are not introduced. Then, after that, if the silicon seed crystal is lowered at a low speed and melted until the tip portion of the silicon seed crystal has a desired thickness, a steep temperature gradient does not occur, and therefore slip dislocations are generated in the silicon seed crystal even at the time of melting. It will not be introduced. And finally, if the silicon seed crystal is slowly pulled up, since the silicon seed crystal has a desired thickness and no dislocations, it is not necessary to perform necking, and since the strength is sufficient, the silicon seed crystal can be thickened to a desired diameter as it is. It is possible to grow a silicon single crystal.

As described above, in the usual necking seeding method, as a method of reducing the initial dislocation density, it is necessary to reduce the heat retention and heating of the silicon seed crystal on the melt and the thermal shock during seeding. Although various shapes and methods have been disclosed, there is a limit to the thickness of the neck, and it has become impossible to follow a single crystal rod having a large diameter and a high weight. Therefore, an ultimate method that can withstand the above-mentioned increase in diameter and weight and that does not cause dislocation during seeding has been established as a dislocation-free seeding method without necking.

However, the problem with this dislocation-free seeding method is its success rate without dislocation. That is, in this method, once dislocations are introduced into the silicon seed crystal, the silicon seed crystal cannot be redone unless the silicon seed crystal is exchanged. Therefore, it is particularly important to improve the dislocation-free success rate. In this case, even if seeding is performed without dislocations, the tapered tip portion of the silicon seed crystal may be left in the vicinity of the melting point of silicon after being melted for a predetermined length, or depending on the time required to start crystal growth. There is a phenomenon in which slip dislocations occur and the dislocations increase. As a result of investigating and investigating the cause of such a phenomenon, it was found that the oxide film formed on the seed crystal surface was largely involved as a source of the phenomenon. A similar tendency is observed in the case of the conventional necking seeding method, and it has been found that this phenomenon is one of the causes for the reduction of the dislocation-free success rate.

[0012]

Therefore, the present invention has been made in view of such conventional problems, and reduces the dislocation-free success rate in any of the necking seeding method and the dislocation-free seeding method. A method for treating a silicon seed crystal, which improves the productivity and yield of a silicon single crystal,
It is a main object to provide a silicon seed crystal obtained by this treatment and a method for producing a silicon single crystal in which a single crystal ingot is grown using this silicon seed crystal.

[0013]

[Means for Solving the Problems] To solve the above problems
The present invention is a method for treating a silicon seed crystal used for growing a silicon single crystal by the Czochralski method,
Before contacting the silicon seed crystal with the silicon melt,
This is a method for treating a silicon seed crystal, characterized in that the oxide film on the surface of the silicon seed crystal is removed.

In this way, the seed crystal material cut out from the silicon single crystal rod is processed and set in the seed holder in the furnace of the single crystal pulling machine, and immediately before it is lowered and brought into contact with the silicon melt, If the oxide film formed on the surface of the silicon seed crystal is removed, even if interstitial silicon atoms are injected near the solid-liquid interface of the silicon seed crystal during the seeding and subsequent necking steps, the side surface of the silicon seed crystal will be affected. Since it diffuses outward, slip dislocations are hardly generated, and the dislocation-free success rate can be improved.

In this case , as a method for removing the oxide film on the surface of the silicon seed crystal, the oxide film on the surface of the silicon seed crystal is easily removed by subjecting the silicon seed crystal to at least hydrofluoric acid solution treatment outside the furnace of the pulling machine. Therefore, the occurrence of slip dislocation due to the oxide film is almost eliminated, and the dislocation-free success rate can be improved.

Then, the present invention provides a method for removing an oxide film on the surface of a silicon seed crystal, in which the seed crystal is held in a seed holder in a puller furnace and then oxidized by an etching action in an inert gas in a high temperature atmosphere. A method for treating a silicon seed crystal, which comprises removing the film. In this way, after holding the silicon seed crystal in the seed holder in the puller furnace,
If the oxide film is removed by an etching action in an inert gas under a high temperature atmosphere, a natural oxide film formed after the hydrofluoric acid treatment described above and before seeding a silicon melt with a silicon seed crystal. Since it can be removed immediately before seeding, the generation of slip dislocations due to the oxide film is almost eliminated, which contributes to the improvement of the productivity of dislocation-free silicon single crystals.

In this case , it is desirable that the atmosphere gas is argon or an inert mixed gas containing argon, and that the flow rate of the atmosphere gas be higher than the flow rate at the time of pulling the single crystal rod. By doing so, the oxide film on the surface of the silicon seed crystal is etched and removed by the etching action of argon gas in combination with the high temperature state in the furnace, and the silicon surface is exposed, so that the occurrence of slip dislocations due to the oxide film is almost eliminated. The silicon single crystal can be pulled up without dislocation. Then, if the flow rate of the atmospheric gas is made higher than the flow rate at the time of pulling the single crystal rod, the rise of the oxidizing gas (eg, SiO) evaporated from the silicon melt can be suppressed, so that the etching action by the atmospheric gas can be suppressed. Will play a role in helping.

Next, the invention described in the present invention is a method for producing a silicon single crystal in which a single crystal ingot is grown using a silicon seed crystal by the Czochralski method. After removal by acid aqueous solution treatment, the silicon seed crystal is held in a seed holder in a puller furnace, and then argon or an inert mixed gas containing argon is supplied as an atmospheric gas at a flow rate higher than that at the time of pulling the single crystal rod. Meanwhile, after removing the oxide film by etching at high temperature under an inert gas atmosphere, the silicon single crystal is brought into contact with the silicon melt to pull up the silicon single crystal. Is.

As described above, when a wet hydrofluoric acid treatment and an etching treatment with a dry inert gas are used together as a method for removing the oxide film on the surface of the seed crystal, the silicon seed crystal is formed before it comes into contact with the melt. Since the oxide film is removed, the occurrence of slip dislocations due to the oxide film is almost eliminated, and the productivity and yield of dislocation-free silicon single crystals can be improved.

In this case, in the above- described method for producing a silicon single crystal, if a columnar or prismatic silicon seed crystal is used and a single crystal ingot is grown by a seeding method for necking, these silicon seeds can be grown. Since the crystal is obtained by removing the oxide film by the above treatment method, the occurrence of slip dislocations due to the oxide film is almost eliminated, and even if the thickness of the drawing is made relatively thick, it is possible to make dislocation-free. The productivity and yield of dislocation-free silicon single crystal are improved.

Further, in this case, in the above- described method for producing a silicon single crystal, a silicon seed crystal having a pointed shape or a shape in which a pointed tip is cut off is used, and necking is not performed. When a single crystal ingot is grown by the dislocation seeding method, these silicon seed crystals are obtained by removing the oxide film by the above treatment method.
The occurrence of slip dislocations due to the oxide film is almost eliminated, and the dislocation-free success rate can be improved.

[0022] Then, the invention described in this invention, the
It is a silicon seed crystal processed by any one of the processing methods. Since most of the oxide film formed on the surface of this silicon seed crystal before contact with the silicon melt is removed, slip dislocations caused by the oxide film may be introduced in the steps after seeding. Therefore, the dislocation-free success rate can be improved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below, but the present invention is not limited thereto. The inventors of the present invention, in the case of growing a single crystal ingot, in any of the above-mentioned seeding method of performing necking and dislocation-free seeding method of not performing necking, when the dislocation-free success rate does not reach a satisfactory level. And investigate the cause,
As a result of investigation, it was found that there is a problem with the oxide film formed on the surface of the silicon seed crystal as a source of this dislocation.

As is well known, when an oxide film is formed on the surface of a silicon crystal, interstitial silicon atoms are implanted. If this is considered in reverse, it can be said that when an oxide film is formed on the surface, outward diffusion of interstitial silicon is suppressed. Therefore, a mixed acid treatment is usually performed as a strain removing step after the machining of the silicon seed crystal, but as a result, an oxide film is formed on the surface, and this oxide film is injected from the melt interface during seeding by the above action. It can be construed as hindering the out-diffusion of the interstitial silicon atoms generated.

Further, even if the oxide film is removed with a hydrofluoric acid aqueous solution after the mixed acid treatment, a natural oxide film is formed if the oxide film is exposed to the air for a long time. It can be easily imagined that it acts to prevent outward diffusion of interstitial silicon atoms. Whether it is an oxide film formed by mixed acid treatment or a natural oxide film, if it is exposed to the high temperature atmosphere in the furnace of the puller, the oxidation will try to proceed to the inside. It is considered that not only the diffusion is hindered, but also an action of newly injecting interstitial silicon atoms occurs.

Therefore, as a measure for promoting the outward diffusion of interstitial atoms and preventing the occurrence of slip dislocations, the removal of the oxide film on the surface of the silicon seed crystal was attempted, and the following conditions were set to cause the oxide film to be generated. It was possible to prevent the occurrence of slip dislocation and to improve the success rate of dislocation-free.

First, in a seed crystal material cut out from a silicon single crystal, particles are usually removed by ultrasonic cleaning, and then a strained layer generated by machining is removed by a mixed acid treatment. However, it is inevitable that an extremely thin oxide film is formed in this process.

Here, the ultrasonic cleaning is a method widely used as a non-contact scrubbing method, and is 20 to 80 k.
When ultrasonic vibration of Hz is applied to the cleaning liquid, a pressure difference is generated in the cleaning liquid and bubbles are generated. The burst of the bubbles scrubs the surface of the seed crystal for cleaning. The cleaning liquid is usually
Ultrapure water is effective for removing organic fine particles, and a 1: 1 mixture of ethanol and acetone is effective for removing inorganic fine particles. The mixed acid treatment is a step of removing the strained layer after machining the seed crystal material with a mixed aqueous solution of hydrofluoric acid-nitric acid-acetic acid.

In the present invention, the oxide film formed by this mixed acid treatment, which causes slip dislocations, is removed by washing with at least a hydrofluoric acid aqueous solution. For example, it is sufficient to immerse the seed crystal in a 5% hydrofluoric acid aqueous solution for about 10 minutes.

Even after removing the oxide film with the hydrofluoric acid solution after the mixed treatment of the seed crystal, it was exposed to the air outside the furnace for a long time until it was set in the seed holder in the furnace of the single crystal pulling machine. Then, a natural oxide film is formed, which acts to prevent outward diffusion of interstitial silicon atoms. Furthermore, if seeds are dropped onto the silicon melt surface for seeding in the furnace, they will be exposed to the high temperature atmosphere in the furnace and oxidation will proceed to the inside, further promoting the outward diffusion of interstitial silicon atoms. It will interfere, and it is considered that interstitial silicon atoms are newly injected.

Therefore, it was judged to be extremely effective to remove the oxide film by the time immediately before the silicon seed crystal was brought into contact with the silicon melt in the furnace, and a method for removing the oxide film in the furnace was established. In this method for removing an oxide film on the surface of a silicon seed crystal, the silicon seed crystal is held by a seed holder in a puller furnace, and then the oxide film is removed by an etching action in a high temperature, inert gas atmosphere. In this way, after holding the silicon seed crystal in the seed holder inside the puller furnace, the oxide film is removed by the etching action in the inert gas under a high temperature atmosphere. Since it is possible to remove the natural oxide film formed before seeding with the silicon melt immediately before seeding,
The occurrence of slip dislocations due to the oxide film is almost eliminated, and the success rate of dislocation-free can be improved.

In this case, the atmosphere gas is preferably argon or an inert mixed gas containing argon.
By doing so, since the inside of the furnace is already in a high temperature state, the oxide film on the surface of the silicon seed crystal is easily removed by being etched by the etching action of argon gas in combination with the high temperature state, and the silicon surface is exposed. . Therefore,
Since seeding is performed with a silicon seed crystal having no oxide film, the occurrence of slip dislocations due to the oxide film is almost eliminated,
A silicon single crystal can be pulled up without dislocation.

In this case, it is desirable that the flow rate of the atmospheric gas is made higher than that at the time of pulling the single crystal rod.
This makes it possible to suppress the rise of the oxidizing gas (eg, SiO) that evaporates from the silicon melt,
It serves to assist the etching action by the inert gas. Further, the position of the silicon seed crystal to be processed in the height direction is likely to be oxidized by the SiO gas if it is directly above the silicon melt, so that it should be positioned some distance from the molten metal surface in the flow of the inert gas. Good to do.

The method for removing an oxide film on the surface of a silicon seed crystal according to the present invention described above uses the cylindrical or prismatic silicon seed crystal (the tip is a flat end surface) shown in FIGS. 1A and 1B. It can be applied to seeding methods using and necking. When a single crystal ingot is grown using a silicon seed crystal having such a shape from which the oxide film has been removed by the above treatment method, the occurrence of slip dislocations due to the oxide film is almost eliminated, and the thickness of the seed aperture can be made relatively small. Even if thickened, dislocations can be removed, and the dislocation-free success rate is significantly increased.
Productivity and yield are improved.

The present invention is based on FIG.
Dislocation-free seeding method without necking using a silicon seed crystal having a sharp tip or a truncated tip as shown in (D), (E) and (F) Can also be applied to the case of growing a single crystal ingot. Since the silicon seed crystal having such a shape is obtained by removing the oxide film by the above-mentioned processing method, the outward diffusion of interstitial silicon atoms is facilitated, slip dislocations are hard to enter, and the dislocation-free success rate is improved. Can be made.

As described above, after the silicon seed crystal is molded and processed, the silicon seed crystal subjected to ultrasonic cleaning and mixed acid treatment is treated with at least a hydrofluoric acid aqueous solution to remove the oxide film, and then the silicon seed crystal is removed. Is held in the seed holder in the furnace of the pulling machine, and then argon or an inert mixed gas containing argon is allowed to flow as an atmosphere gas at a flow rate higher than that at the time of pulling the single crystal rod, and the etching action is performed in a high temperature, inert gas atmosphere. After removing the oxide film by the method, if the silicon seed crystal is brought into contact with the silicon melt to pull up the silicon single crystal, there is almost no oxide film on the surface of the silicon seed crystal. As it easily diffuses outward, slip dislocations are less likely to enter,
A silicon single crystal can be pulled up with a high dislocation-free success rate.

In this case, in the seeding method of necking, a thick drawing with a diameter of about 5 mm or more is possible. Even in the dislocation-free seeding method without necking, the melted diameter of the seed tip can be increased to about 5 mm or more. Because you can
It is possible to sufficiently cope with future increase in diameter and weight of the single crystal ingot, and it is possible to remarkably improve productivity and yield.

[0038]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. (Example 1) As a silicon seed crystal of a dislocation-free seeding method without necking, as shown in FIG.
The tip of a round bar having a diameter of 15 mm was processed into a conical shape, subjected to ultrasonic cleaning and mixed acid treatment, and then subjected to hydrofluoric acid aqueous solution treatment (immersing in a 5% hydrofluoric acid aqueous solution for 10 minutes) to remove the surface oxide film. The silicon seed crystal thus treated was set in the seed holder in the furnace of the puller within 1 hour, and immediately evacuated and replaced with 100% argon gas. After that, the temperature was kept above the surface of the silicon melt for 20 minutes, and melted at a constant rate of 3 mm / min to a diameter of 7 mm. Next, pull up the silicon seed crystal at a speed of 0.5 mm / min,
A single crystal cone portion was produced, and a single crystal straight body portion having a diameter of 150 mm was pulled up to 10 cm and rounded. This single crystal rod was cooled, taken out from the furnace, and subjected to Secco etching treatment to investigate the state of occurrence of slip dislocation.

As a result, no slip dislocations occurred in 9 single crystal rods pulled up. That is, the dislocation-free success rate (%), which is a value in percentage of the number of silicon single crystals that did not generate dislocations with respect to the number of pulled silicon single crystals, was 90%. Here, Seco (Secc
o) Etching refers to first removing the surface by etching with a mixed aqueous solution of hydrofluoric acid and nitric acid, and then etching with a mixed aqueous solution of K ₂ Cr ₂ O ₇ , hydrofluoric acid and water. It is used to confirm the occurrence.

Example 2 As a silicon seed crystal of a dislocation-free seeding method without necking, a round bar having a diameter of 15 mm was processed into a conical shape, and ultrasonic cleaning and mixed acid treatment were performed. The silicon seed crystal thus treated was set in the seed holder in the furnace of the puller within 1 hour, and immediately evacuated and replaced with 100% argon gas. afterwards,
The flow rate of argon gas is 150% of that when pulling the single crystal straight body part.
While flowing a large flow rate, the temperature was kept for 60 minutes right above the surface of the silicon melt, and melted at a constant rate of 3 mm / min to a diameter of 7 mm. Next, the silicon seed crystal is 0.5 mm /
The single crystal cone portion was produced by pulling up at a speed of min, and the single crystal straight body portion having a diameter of 150 mm was pulled up to 10 cm and rounded. This single crystal rod was cooled, taken out from the furnace, and subjected to Secco etching treatment to investigate the state of occurrence of slip dislocation. As a result, 10 single crystal rods were pulled up and no co-slip dislocations were generated, and the dislocation-free success rate (%) was 100.
%Met.

Comparative Example As a silicon seed crystal of a dislocation-free seeding method without necking, the tip of a round bar having a diameter of 15 mm was processed into a conical shape, and ultrasonic cleaning and mixed acid treatment were performed. The silicon seed crystal thus treated was set in the seed holder in the furnace of the puller within 1 hour, and immediately evacuated and replaced with 100% argon gas. afterwards,
The temperature was kept above the surface of the silicon melt for 20 minutes, and melted at a constant rate of 3 mm / min to a diameter of 7 mm. next,
A silicon seed crystal was pulled at a rate of 0.5 mm / min to produce a single crystal cone portion, and a single crystal straight body portion having a diameter of 150 mm was pulled up to 10 cm and rounded. This single crystal rod was cooled, taken out from the furnace, and subjected to Secco etching treatment to investigate the state of occurrence of slip dislocation. As a result, no slip dislocations were generated in 6 single crystal rods pulled up, and the success rate of dislocation-free was 60%. All of the four slip dislocations were generated from the vicinity of the welded portion of the tip cone portion.

As is clear from the examples and comparative examples described above, if the oxide film removal treatment on the surface of the silicon seed crystal is performed at least before the silicon seed crystal is brought into contact with the silicon melt, the dislocation-free success rate is significantly improved. It turns out that it can be improved.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, has substantially the same configuration as the technical idea described in the scope of the claims of the present invention, and has any similar effect to the present invention. It is included in the technical scope of the invention.

For example, in the embodiment of the present invention, the diameter 15
Although a 0 mm (6 inch) silicon single crystal ingot is grown, the recent 200 mm (8 inch) to 400 mm (1
It is possible to cope with the increase in diameter to 6 inches). In the present invention, as a general rule, pulling of a single crystal rod of any diameter, length, and weight can be applied without using a crystal holding device or the like as long as it is at or below the physical property limit value of silicon.

Further, the present invention is not limited to the ordinary Czochralski method, but the MCZ method (Magnetic Field Applied Czochralski Cry) in which a magnetic field is applied when pulling a silicon single crystal.
Needless to say, the term “Czochralski method” used in the present specification includes not only the ordinary Czochralski method but also the MCZ method.

[0046]

As described above, according to the present invention,
It is possible to prevent dislocation from occurring due to the oxide film on the surface of the silicon seed crystal, and to achieve a dislocation-free success rate of almost 100%. This is effective not only in the dislocation-free seeding method that does not require necking, but also in the seeding method that performs necking, and it becomes possible to adapt to the large diameter and high weight of single crystal rods, and to improve productivity, The yield and the cost can be significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing the shape of a silicon seed crystal used in the present invention. (A) cylindrical seed crystal, (B) prismatic seed crystal, (C)
Conical seed crystal, (D) pyramidal seed crystal, (E) conical seed crystal with a sharp tip cut off, and (F) conical seed crystal with a sharp tip cut off.

Continuation of the front page (56) Reference JP-A-9-194291 (JP, A) JP-A 64-37491 (JP, A) JP-A 5-139880 (JP, A) JP-A-6-271384 (JP , A) JP 7-165487 (JP, A) JP 8-290994 (JP, A) JP 9-165297 (JP, A) JP 9-249486 (JP, A) JP 9-255485 (JP, A) JP-A-10-203898 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00

Claims (7)

(57) [Claims] 1. A method for treating a silicon seed crystal used for growing a silicon single crystal by the Czochralski method, wherein an oxide film on the surface of the silicon seed crystal is removed before the silicon seed crystal is brought into contact with a silicon melt. By the way
Yes, as the method for removing the oxide film on the surface of the silicon seed crystal
Hold the silicon seed crystal in the seed holder inside the puller furnace
After that, the flow rate of the atmospheric gas is adjusted to the flow rate when pulling the single crystal rod.
Flow as much as possible and etch in an inert gas in a high temperature atmosphere.
A method for treating a silicon seed crystal, which comprises removing an oxide film by a ching action . 2. The method for treating a silicon seed crystal according to claim 1, wherein the silicon seed crystal is also subjected to at least hydrofluoric acid solution treatment as a method for removing the oxide film on the surface of the silicon seed crystal. Wherein the ambient gas is, claims, characterized in that an inert gas mixture containing argon or argon
Item 2. A method for treating a silicon seed crystal according to Item 1 . 4. A method for producing a silicon single crystal in which a single crystal ingot is grown using a silicon seed crystal by the Czochralski method, wherein after the oxide film on the surface of the silicon seed crystal is removed by at least hydrofluoric acid solution treatment, The silicon seed crystal is held in a seed holder in a puller furnace, and then argon or an inert mixed gas containing argon as an atmospheric gas is flowed at a flow rate higher than that at the time of pulling a single crystal rod,
A method for producing a silicon single crystal, which comprises removing an oxide film by etching at a high temperature under an inert gas atmosphere, and then bringing a silicon seed crystal into contact with a silicon melt to pull up a single crystal rod. 5. The method for producing a silicon single crystal according to claim 4 , wherein a columnar or prismatic silicon seed crystal is used, and the single crystal ingot is grown by a seeding method for necking. Method for producing single crystal. 6. The method for producing a silicon single crystal according to claim 4 , wherein a silicon seed crystal having a pointed shape or a shape obtained by cutting a pointed tip is used, and necking is not performed. A method for producing a silicon single crystal, which comprises growing a single crystal ingot by a dislocation seeding method. 7. A silicon seed crystal processed by the processing method according to claim 1 .