JPH03159985A - Process for producing single crystal - Google Patents

Abstract

PURPOSE:To control oxygen concentration in a crystal and obtain a single crystal having uniform oxygen concentration using Czochralski process by attaching a cylindrical barrier wall under a heat-radiation shielding member and adjusting the depth of the barrier wall immersed in molten liquid. CONSTITUTION:A single crystal 7 is produced by an apparatus having a crucible 3 for melting raw materials, a means for pulling up a single crystal 7 from the molten materials, and a heat-radiation shielding member 8 placed around the pulling-up zone of the single crystal 7 above the crucible 3. In the above apparatus for Czochralski process, a cylindrical barrier wall 9 is placed under the shielding member 8 to divide the molten material into an inner region and an outer region while leaving the lower part of the molten liquid to be movable between the regions. The depth of the barrier wall 9 immersed in the molten liquid is made to be adjustable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a single crystal by the Czochralski method (CZ method).

[Conventional technology]

As a single crystal lengthening method, a seed crystal is immersed in the melt in a crucible,
This is rotated and pulled upward to grow a single crystal at the lower end of the seed crystal, the so-called Czochralski method (CZ method).
has been widely known.

In general, single-crystal silicon is produced by the Czochralski method (CZ method), for example, by placing polycrystalline silicon in a crucible, heating it with a heater, and melting it. This is done by dipping a seed crystal inside and pulling it upwards while rotating it, thereby making the single crystal grow taller at the bottom of the seed crystal.

The Si single crystal grown from a quartz crucible by this method usually contains 13~]. It contains about 8×10” alms/cc of oxygen. This oxygen is taken into a certain long crystal from the quartz J1J pot through the melt.

FIG. 7 is a schematic vertical sectional view of a single crystal lengthening device, in which a melt 21 of a raw material for single crystal is contained in a quartz crucible 20 rotatably supported by a support shaft 3a.

Heaters 40 are arranged concentrically outside the crucible 20. A seed crystal (not shown) suspended from a pulling shaft 70 is immersed in the melt 2l, and the seed crystal 80 is pulled upward while being rotated to elongate the single crystal 80 to a certain length. In FIG. 7, dashed arrows A-D indicate the process by which oxygen is incorporated into the crystal.

A: At the interface between the melt 21 and the quartz crucible 20, quartz dissolves Si (h→Si+20...(1)) B: Oxygen moves due to convection within the melt 21 C: The melt 2l and It blooms as StO at the interface with the single crystal 80 (growth interface).

Si+O−+SiO↑ (2) D: Oxygen in the melt 21 is taken into the single crystal 80 at the interface (growth interface) between the melt 21 and the single crystal 80.

Si (in Melt) → Si (in Crystal
) - (3) In each oxygen uptake process of AC and D, if the moving speed of oxygen is X, Y, 7, respectively, and the amount of oxygen in 2 liters of melt is Q, how much oxygen is taken into the single crystal 80? =X-Y- (4) Represented by dt.

However, the influence on the oxygen uptake processes of A, C, and D is largely due to the process of B, that is, the convection within 2 liters of the melt, and most of the oxygen in the crucible is absorbed by the crystal raw material polycrystalline silicon in the quartz crucible. During the melting process, silicon is supplied from the surface of the quartz crucible into the molten liquid, and is stirred into the molten liquid by forced convection of the molten liquid due to the rotation of the crucible and thermal convection due to the internal temperature difference of the molten liquid in the crucible. In addition to being evaporated from the crystal, some of it is transported to the long interface of the single crystal and incorporated into the single crystal.

FIG. 8 shows typical convection that occurs within the melt.

In the figure, the arrow a indicates the thermal convection that flows due to the driving force acting on the entire melt as a buoyancy difference between each part of the melt 2l, and the arrow b indicates the driving force acting on the crystal interface as the centrifugal force due to the rotation of the single crystal 80. arrow C indicates forced convection due to crystal rotation that flows particularly strongly near the interface, and arrow C indicates a driving force acting on the interface between the crucible 20 and the melt 21 as a centrifugal force due to the rotation of the crucible 20, causing a particularly strong flow near the interface. Indicates forced convection due to strong flowing crucible rotation,
Arrow d indicates Marangoni convection where a driving force acts on the melt surface as a surface tension difference and flows particularly strongly on the melt surface. Of these, when the temperature of the melt 21 is constant, the forced convection due to the rotation of the crucible indicated by the arrow C is caused by the relative velocity V between the quartz and the melt 2l.
increases the dissolution rate of quartz. this is,
This is because by increasing the relative velocity V, the thickness of the diffusion layer existing at the interface between the quartz and the melt 21 is reduced, the diffusion rate is increased, and the oxygen concentration in the melt 21 is increased.

On the surface of the melt 21 where the Marangoni convection shown by the arrow d acts, the oxygen brought in by the thermal convection shown in a and the forced convection caused by the rotation of the crucible shown in C evaporates, and a diffusion layer with a low oxygen concentration is formed near the surface. Ru. In this diffusion layer, the SiO partial pressure is maintained at a state much lower than the equilibrium partial pressure by exhausting the generated SiO with the inert gas flow, and the evaporation rate from the surface of the melt 21 to the atmosphere side is extremely low. Because it is big, it is imposing. The thickness of this diffusion layer is determined by the gas flow rate that evacuates the surface and the convection that supplies oxygen. Therefore, thermal convection and Marangoni convection transport the melt with low oxygen concentration toward the Yuishinaga interface.

Heat convection occurs under the crystal growth interface. Convection flowing from the melt surface with low oxygen concentration to the lower part of the long interface introduced by Marangoni convection d and forced convection b due to crystal rotation move outward from the center and reduce the oxygen concentration of the melt at the surface of the melt. There is a convection current that flows in a direction that prevents liquid from entering. In other words, the oxygen concentration under the crystal grain interface is thought to change depending on the ratio of convection flowing from the outside to the center of the crucible and convection flowing from the center to the outside.

Next, we will discuss the actual control of oxygen concentration in the crystal. CZ
When pulling a Si single crystal with a straight body of a constant diameter from a quartz crucible of a constant diameter by the method, the rotation of the crucible and the rotation of the crystal are S.
When t is kept constant during single crystal pulling, it is the early stage of pulling, that is, at the tip side of the crystal, there is a lot of melt in the crucible, the contact area between the melt and the crucible is large, and the amount of oxygen dissolved into the melt. The oxygen concentration is high due to the large amount of On the other hand, in the latter half of pulling, that is, at the rear end of the crystal, there is less melt in the crucible, the contact area between the melt and the crucible is small, and the amount of oxygen dissolved into the melt is small, so the oxygen concentration is lower than at the front end. . Therefore, the oxygen concentration gradually decreases from the front end to the rear end of the crystal. For this reason, the rotation of the crucible is gradually increased so that the amount of dissolved oxygen increases with the pulling, thereby making it uniform in the pulling axis direction, that is, in the crystal growth direction.

However, by increasing the rotation of the crucible, the surface of the melt vibrates7, lattice defects are generated inside the crystal, and the formation of dislocations in the single crystal is promoted. Furthermore, there is a problem in that the low oxygen concentration melt at the surface of the melt invades under the elongated crystal interface, worsening the oxygen concentration distribution within the interface.

Furthermore, simply controlling the rotation of the crucible can reduce the oxygen level in the melt to a medium oxygen level (15 to 18 x 10 l7 atms/cc).
), low oxygen level (13-15 X 10” at
ms/cc). For this reason,
By changing the positional relationship of the crucible with respect to the heater heat generation length, or by changing the heater heat generation length itself, the temperature distribution at the interface between the melt and the quartz crucible is changed, and the amount of oxygen dissolved in the melt is controlled. A method is being taken.

In addition, in Japanese Patent Application Laid-open No. 54-150378, as shown in FIG. 9, in a single-crystal pulling device W similar to that shown in FIG.
L-shaped rod-shaped radiant heat shields 10a, 10a are provided to block radiant heat generated from the crucible wall and the surface of the melt 21, thereby improving the pulling speed of the single crystal 80.

[Problem to be solved by the invention]

By the way, as mentioned above, the vicinity of the surface of the melt 21 is filled with sparged S.
By evacuation of iO with an inert gas flow, the SiO partial pressure is kept much lower than the equilibrium partial pressure, forming a diffusion layer with a low oxygen concentration. Since the rate of blooming from the melt surface to the atmosphere side is constant, if the radiant heat shields 10a, 10a are not used, the oxygen concentration in the melt can be increased by increasing the number of crucible rotations per single boiling time, and the oxygen concentration in the melt can be increased. The oxygen concentration in the single crystal increases.

On the other hand, when the radiant heat shields 10a, 10a are used, the oxygen concentration in the obtained single crystal decreases due to an increase in the number of rotations of the crucible per unit time. In order to elucidate the cause of this, the present inventor conducted research and experiments and found the following. That is, there is a gas diffusion layer of SiO emitted directly above the surface of the melt, and the radiant heat shields 10a, 10a
By using , the inert gas introduced from above inside the furnace flows through the lower end of the radiant heat shield [Oa,]Oa and the melt surface, increasing its flow rate and reducing the thickness of the gas diffusion layer. As a result, the SiO partial pressure on the melt surface becomes even lower, promoting the blooming of SiO.

The rate of this SiO blooming is greater than the rate of oxygen replenishment to the melt surface due to increased crucible rotation, so the forced convection C is strengthened by increased crucible rotation, causing a drop in the area just below the melt surface. More of the oxygen melt is brought under the crystal growth interface, and the oxygen concentration in the resulting single crystal decreases.

Even when the radiant heat shields 10a and 10a are used, as in the case where they are not used, it is difficult to control the oxygen level in the melt to a medium oxygen level or a medium oxygen level just by controlling the rotation of the crucible. It is. Therefore, the amount of oxygen dissolved into the melt is controlled by changing the vertical relationship of the crucible with respect to the heater heat generation length, or by changing the heater heat generation length itself.

However, for example, {i'7. If the crucible 8 is directly aligned with the center of the heating length of the heater, the temperature gradient on the surface of the melt cannot be maintained between the crucible edge and the pulling center, causing a problem that the melt at the crucible edge is assimilated.

Therefore, {+'/W of the crucible for the heat generation length of the heater is determined as
There was a problem in that the amount of Jl used in the pulling furnace had to be changed to LJ for the low-oxygen level and the medium-oxygen level.

The present invention has been made in view of the above circumstances, and it fuses the cylindrical partition wall in order to change the flow of convection that supplies the low oxygen concentration diffusion layer formed under the radiant heat shield to the crystal long interface. By immersing the single crystal in a liquid and changing the immersion depth, the oxygen concentration in the single crystal can be controlled, resulting in low oxygen concentration (II
XIO17atm/cc) ~ High oxygen concentration (22X10
It is an object of the present invention to provide a single crystal production method that can control the oxygen concentration in a single crystal over a wide range up to "atm/r.c."

[Means to solve the problem]

The single crystal pulling method of the present invention includes a crucible for heating and melting a single crystal raw material to be elongated, a means for pulling the single crystal from the melt in the crucible, and a means for pulling the single crystal from the melt in the crucible. In a method for producing a single crystal using a single crystal growing apparatus having a radiant heat shield disposed above and around a pulling area of the single crystal, a radiant heat shield disposed below the radiant heat shield and below the melt surface. Then, with the melts communicating with each other, a cylindrical partition wall is installed that divides the single crystal into an inner region that extends above and below the melt surface, and an outer region thereof, and the cylindrical partition wall is drawn into the melt of the cylindrical partition wall. It is characterized by controlling the oxygen concentration in the single crystal by changing the immersion depth.

〔principle〕

The principle of the present invention will be explained below based on the drawings.

FIG. 4 is a schematic vertical cross-sectional view showing a conventional single crystal elongation device in which a radiant heat shield 10a and IOa are arranged, similar to FIG.
The fifth and sixth factors are the radiant heat shield 10a in FIG.
, 1'Oa, a cylindrical partition wall 9 made of quartz is immersed in the melt surface directly below the lower end of the quartz crystal. Figure 5 shows the case where the immersion depth is shallow, and Figure 6 shows the case where the immersion depth is deep. shows.

In FIG. 4, the radiant heat shield 10a10 is
^r gas is introduced into the radiant heat shield 10a, ]. The thickness of the SiO gas diffusion layer just above the melt surface directly under the lower end of Oa is reduced, promoting the smoke-off of SiO, and as described above, the oxygen concentration in the single crystal decreases as the crucible rotation speed increases.

Further, by the thermal convection a and the forced convection C (hollow arrow mark in the figure) caused by the crucible rotation, the forced convection b caused by the crystal rotation is changed into a convection flowing from the outside of the crucible 2 toward the crystal growth interface. As a result, a large amount of the low oxygen concentration melt in the diffusion layer X is brought to the crystal growth interface.

In FIG. 5, as described above, the radiant heat shields 10a, 1
The cylindrical partition wall 9 is immersed in the melt surface below 0a, and the immersion depth is shallow (for example, about 2 mm). The cylindrical partition wall 9 includes
The rotation of the crucible has the effect of blocking the flow of the melt with high oxygen concentration flowing at the interface between the crucible 20 and the melt 21, and the diffusion layer
The amount of oxygen supplied to the body is limited. As a result, the diffusion layer
The oxygen concentration of is further reduced, and the thickness of the diffusion layer X is increased. On the other hand, the immersion depth of the cylindrical partition 9 is shallow, and the amount of oxygen supplied from the quartz cylindrical partition 9 into the melt is very small. Further, thermal convection a and forced convection C (white arrow in the figure) due to crucible rotation are hardly blocked. Therefore, the shallower the immersion depth of the cylindrical partition wall 9, the more the low-oxygen melt in the diffusion layer X is transported below the crystal or long interface, and the oxygen concentration in the single crystal decreases.

In FIG. 6, the immersion depth of the cylindrical partition wall 9 is deep (for example, about 50 mm). In this case as well, the amount of oxygen supplied to the diffusion layer X is limited and the thickness of the diffusion layer χ increases, as in the case where the immersion depth is shallow. However, the cylindrical partition wall 9 made of quartz
Since the contact area between the cylindrical partition wall 9 and the melt 21 is large, a large amount of oxygen is supplied from the cylindrical partition wall 9 into the melt. Also, the radiant heat shield 10
Thermal convection a that transports the low oxygen concentration diffusion layer X directly under the lower end of a and lOa to a certain long interface and the forced convection C (hollow arrow mark in the figure) due to the rotation of the crucible are blocked. Therefore, the cylindrical partition wall 9
The deeper the immersion depth, the more the high oxygen concentration melt at the bottom of the crucible will be supplied below the growth interface, and the oxygen concentration in the single crystal will increase.

[Effect]

In the single crystal manufacturing method of the present invention, a cylindrical partition wall is immersed in the melt under the radiant heat shield. The cylindrical partition wall blocks the flow of high oxygen concentration flowing at the interface between the crucible and the melt due to the rotation of the crucible. As a result, the low oxygen concentration diffusion layer under the radiant heat shield is further reduced and its thickness is increased. The shallower the immersion depth of the cylindrical partition wall into the melt, the more the diffusion layer is supplied to the bottom of the long interface of the crystal due to convection in the melt, and the oxygen concentration in the single crystal is reduced. On the other hand, the deeper the immersion depth, the more the convection in the melt that transports the diffusion layer below the long interface of the crystal is blocked, and the melt with high oxygen concentration at the bottom of the crucible is mainly supplied under the long interface. As a result, the oxygen concentration in the single crystal increases.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a schematic cross-sectional view of a crystal elongation apparatus used in carrying out the method of the present invention, in which 1 is a chamber, 2 is a heat retaining wall, 3 is a crucible, and 4 is a heater. A heat insulating wall 2 is lined around the side of the chamber 1, and a crucible 3 is disposed in the center surrounded by the heat insulating wall 2. A heater 4 is placed between the crucible 3 and the heat insulating wall 2. A gap forming an exhaust air passage is provided between them.

The crucible 3 has a quartz container 3 inside a carbon container 3a.
The upper end of the shaft 3C that penetrates the bottom wall of the changha 1 is connected to the center of the bottom, and the shaft 3c allows the shaft 3c to be rotated and raised and lowered. ing.

At the center of the upper wall of chamber 1, a single crystal pulling l'J1a is opened which also serves as a supply port for atmospheric gas in chamber l. Changha 1 in the part where the pulling port 1a is opened
A pull shaft 5 is erected above, and a chuck 5b is suspended from the upper end of the pull shaft 5 for gripping a seed crystal 5c using a pull shaft 5a.The upper end of the pull shaft 5a is not shown. It is connected to a rotating and lifting mechanism. After the seed crystal 5C is immersed in the melt, the single crystal 7 is made to grow at the lower end of the seed crystal 5c by rotating and raising the seed crystal 5C.

In the −L side of the chamber 1, a radiant screen 8, which is a radiant heat shield made of carbon, is located around the pull-1 draw area of the single crystal 7 and can be raised and lowered by a lifting means arranged at the upper part of the pull chamber 5. A cylindrical partition wall 9 is attached to this radiation screen 8.

The radiation screen 8 has a cylindrical support part 8b on the outer peripheral edge of an annular rim 8a made of carbon, and a hollow inverted truncated cone shape with a diameter decreasing downward from the inner peripheral edge of the annular rim 8a. The tapered portions 8c are respectively provided so as to be inclined as shown in FIG.

FIG. 2 is a perspective view of the cylindrical partition wall 9. The cylindrical partition wall 9 is made of quartz and has supporting pieces 9b erected from a plurality of circumferential locations at the upper end of the cylindrical partition main body 9a. Each of the support pieces 9h passes through a plurality of holes 8d formed in the tapered portion 8c of the radiation screen 8, and is arranged to be able to be raised and lowered by means of raising and lowering means arranged in the pulley 5. Alternatively, each support piece 9b is attached to the radiation screen 8 so that its position can be adjusted in the upward and downward directions by inserting each support piece 9b into a hole 8d formed in the tapered portion 8c of the radiation screen 8 and shifting the pin 1. The position of the cylindrical partition 9 can be such that when the radiant screen 8 is raised, the lower end of the cylindrical partition 9 is not immersed in the melt in the crucible 3, and when the radiant screen 8 is lowered, the radiant screen 9 8 support part 8h
The lower end of the cylindrical partition wall 9 is set at a required height from the inner bottom of the crucible 3 and immersed in the melt to an appropriate depth at the same time as the cylindrical partition wall 9 contacts the heat retaining wall 2.

Note that the means for attaching the cylindrical partition wall 9 to the radiation screen 8 is not particularly limited, and conventionally known bolts, nanototes, or other means may be adopted as appropriate.

Therefore, in the single crystal lengthening apparatus configured as described in -1-2 above, the cylindrical partition wall 9 is initially pulled upward and set so that the cylindrical partition wall 9 does not come into contact with the raw material in the crucible 3. Keep it at 7.

In this state, the crucible 3 is heated by the heater 4, and the raw material contained in the crucible 3 is heated and melted. When the raw material is melted, the elevating means is activated to lower the radiant screen 8 and the cylindrical partition wall 9, and the support part 8h of the radiant screen 8 comes into contact with the support 2al arranged on the upper part of the heat insulating wall 2, and the cylindrical partition wall 9 is set so that the lower end of the partition main body 9a is immersed at an appropriate position 9 under the melt.

The crucible 3 is rotated in the direction of the arrow by a supporting shaft 3c, and a pulling shaft 5a serving as a pulling means is lowered to drop the seed crystal 5c into the melt inside surrounded by a cylindrical partition wall 9. After being immersed in water, it is pulled at a predetermined speed while rotating the pulling shaft 5a.
L growth (average) .5 mm/min), single crystal 7 under seed crystal 5c
Lengthen U7 by a certain length.

Note that if the crucible 3 does not move up and down sufficiently, the cylindrical partition wall 9
It is not necessary to pull it upward in advance.

Further, if the immersion depth of the cylindrical partition wall 9 is not changed during lifting, the cylindrical partition wall 9 can be attached to the radiation screen 8 in advance so as to have a predetermined immersion depth.

The radiant heat shield has a heat insulating effect on the melt surface side, which allows the solidification of SiO evaporated from the melt surface [SiO(gas)→S
It has the function of preventing in(solid)).

As a result, the evaporated SiO is transferred to the cylindrical partition wall 9 and the support piece 9b.
This prevents the foreign matter from adhering to the surface of the melt and falling onto the melt surface.

The crucible 3 of the crystal lengthening apparatus used in this example had a diameter of 16 inches, the cylindrical partition wall 9 had a diameter of 10 inches, and the amount of melt before the start of pulling was 35 kg.

The pulled single crystal had a diameter of 6 inches, the rotation speed of the single crystal during pulling was 15 rpm, and the crucible rotation speed was 5 rpm.
The pulling speed was 1.5 mm/min. Then, the immersion depth of the cylindrical partition wall 9 is set to 2 mm, 5 mm, 10 mm, 30 depths,
The oxygen concentration in the melt was controlled by changing it at five levels of 50 mm. In addition, when the immersion depth was 50 mm, in order to prevent contact between the crucible 3 and the cylindrical partition wall 9 in the latter half of the pulling process, the cylindrical partition wall 9 was raised in synchronization with the rise of the crucible 3 during the pulling process.

FIG. 3 is a graph showing the oxygen concentration versus the pulling length when the single crystal manufacturing method of the present invention is carried out by changing the immersion depth of the cylindrical partition wall 9 as described above.

The vertical axis shows the oxygen concentration (X 10" atms/cc
), and the horizontal axis shows the pulling length (mm).

As is clear from the figure, the deeper the immersion depth of the cylindrical partition wall 9, the higher the oxygen concentration, and the shallower the immersion depth, the lower the oxygen concentration. For example, if the immersion depth is between 50 and 19
An oxygen concentration of ms/cc or higher was obtained.

If the immersion depth is 2 meters, 8 x 10” atms/
The oxygen concentration was below cc. In this way, the control range of oxygen concentration can greatly exceed the normal oxygen concentration range of low and medium oxygen levels of 13 to 18XIO7at...s/cc. Also, the immersion depth is 301Ilm,
When the diameter was 10 mm and 5 layers, it was possible to obtain an oxygen concentration at a low oxygen level. Furthermore, in each case, the variation in oxygen distribution within the crystal plane was 5 to 10%.

Note that if the heating distribution of the melt in the crucible varies depending on the heater heat generation length, the position of the crucible relative to the heater heat generation length, etc., and the oxygen distribution in the pulling direction is not uniform, the cylindrical partition wall 9 may be raised or lowered during pulling. The immersion depth is changed using a device (normally, as the oxygen concentration decreases, the immersion depth of the cylindrical partition wall 9 is increased),
Crystals having an oxygen concentration of -19 in the pulling direction can be obtained.

〔Effect of the invention〕

As detailed above, in the single crystal pulling method of the present invention, the cylindrical partition wall is attached under the radiant heat shield, and the immersion depth of the cylindrical partition wall is varied.

As a result, the radiant heat: The flow of convection that supplies the low oxygen concentration diffusion layer formed under the IxWM body to the crystal growth interface is changed, and the oxygen concentration in the single crystal is controlled.

According to the method of the present invention, it is possible to control the oxygen concentration in a single crystal over a wide range from low oxygen concentration to high oxygen concentration, and it is also possible to obtain a single crystal with a uniform oxygen concentration in the length direction of pulling the single crystal. It has the excellent effect of being

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a single crystal growth device used in carrying out the method of the present invention, Fig. 2 is a perspective view of a cylindrical partition wall, and Fig. 3 is a cylindrical shape when carrying out the method of producing crystals of the present invention. A graph showing the oxygen concentration against the pulling length according to the immersion depth of the partition wall, Fig. 4 is a schematic vertical cross-sectional view of a single crystal lengthening device equipped with a radiant heat shield, Figs. In the figure, the cylindrical partition wall is immersed under the radiant heat shield. Figure 5 shows the case where the immersion depth is shallow, Figure 6 shows the case where the immersion depth is deep, and Figure 7 shows the case where the cylindrical partition wall is immersed under the radiant heat shield. A schematic vertical cross-sectional view showing the process in which oxygen is incorporated into the crystal in the device, FIG. 8 is a schematic vertical cross-sectional view showing the convection that occurs in the melt, and FIG. 9 is a schematic vertical cross-sectional view of a conventional single crystal lengthening device. FIG. 3... Crucible 7... Single crystal 8... Radiant heat shield 9... Cylindrical partition wall

Claims (1)

[Scope of Claims] 1. A crucible for heating and melting raw materials for a single crystal to be grown, means for pulling the single crystal from the melt in the crucible, and a means for pulling the single crystal from the melt in the crucible; In a method for producing a single crystal using a single crystal growth apparatus having a radiant heat shield disposed around a crystal pulling region, the melt is in communication with the melt below the radiant heat shield and below the melt surface. Then, a cylindrical partition wall is installed that divides the area above and below the melt surface into an inner region for pulling the single crystal, and an outer region thereof, and the immersion depth of the cylindrical partition wall into the melt is varied. A single crystal manufacturing method characterized by controlling the oxygen concentration in the single crystal.