JPH05178688A - Pulling up method and pulling up device for single crystal - Google Patents

Abstract

PURPOSE:To prevent the adhesion of a gaseous metal or metal oxide to a single crystal or the mixing thereof in to a melt and to exactly control the oxygen concn. in the single crystal by controlling the detected differential pressure of the gaseous phase parts in and out of a cylindrical body in accordance with a prescribed program during the growth of the single crystal. CONSTITUTION:The pressures in the inside and outside parts of the cylindrical body 4 suspended near a melt surface 3 from the inside wall of a chamber 200 above a crucible 1 are detected respectively by detectors, for example, pressure sensors 5, 6 and are outputted to a central controller 40 at the time of pulling up the single crystal by a Czochralski method. The differential pressure in and out of the cylindrical body 4 is compared and computed with a previously programmed value and a signal is outputted to a valve controller 50 so as to control the differential pressure. The controller 50 sends opening/ closing signals to a valve 12 on a gas supply side and a valve 13 on a discharge side and control the differential pressure in such manner that the differential pressure is maintained at the previously programmed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of growing a single crystal by immersing a seed crystal in a raw material melt melted in a crucible and gradually pulling it up. The present invention relates to a technique for preventing contamination of crystals by metals and metal oxides and controlling the concentration of oxygen taken into a single crystal.

Reference number = P911200002
Page (2/8)

2. Description of the Related Art Conventionally, for improving the oxygen concentration distribution in the axial direction of a pulled single crystal, for example, Japanese Patent Laid-Open No. 1-1 is known.
Japanese Patent No. 60893 discloses a technique of sequentially increasing the flow rate of an inert gas supplied into a pulling apparatus to prevent a decrease in oxygen concentration in a silicon single crystal due to single crystal growth. Further, in Japanese Unexamined Patent Publication No. HEI 1-160892, the oxygen concentration in the axial direction of the single crystal is made constant by raising the crucible that keeps the clearance between the tip of the reflector and the melt surface to correspond to the pulling of the single crystal. A method of converting to the same is disclosed. However, these documents do not mention the usefulness of gas pressure sensing of an inert gas.

On the other hand, as a measure against impurities taken into a single crystal, for example, Japanese Patent Publication Nos. 57-40119 and 58-1080 disclose an upper flat annular rim protruding from the edge of a crucible and an annular shape. Attached to the rim and inclined downward from the inner edge into a cylindrical shape, or
A cover consisting of a conical tapered connection and a silicon monoxide condensate condensed during pulling or agglomerates that flow into the melt during the crystal pulling It is said that it can be effectively controlled by appropriately adjusting the flow velocity and pressure of the gas.
However, it is known that, in the case where a cylindrical one is provided around such a single crystal, the oxygen concentration in the crystal axis direction is usually drastically reduced as the single crystal is pulled up.

[0004]

High-purity silicon is mainly used for a substrate for manufacturing a semiconductor integrated circuit element. This high-purity silicon is mainly manufactured by the Czochralski method, which is one of the pulling methods. Has been done. Oxygen is solid-dissolved in the crystal pulled by this method, and this oxygen traps (getters) metal impurities mixed in in the manufacturing process of the semiconductor integrated circuit device, and improves the electrical characteristics of the device. .. Since the getter action is extremely sensitive to the oxygen concentration, its control occupies an important position in the technique of pulling a single crystal by the Czochralski method. Reference number = P911200002
Page (3/8)

The oxygen of the silicon single crystal being pulled is the oxygen eluted from the quartz crucible and taken into the single crystal as it is pulled. Of course, 90% or more of the oxygen eluted from the quartz crucible into the melt is evaporated as silicon monoxide from the surface of the melt.

On the other hand, the demand for higher quality of the silicon single crystal by the Czochralski method is becoming more and more severe with the improvement of the integration degree of the semiconductor integrated circuit device. In particular, oxygen-induced defects (hereinafter referred to as OSFs) caused by oxygen are considered to directly affect the yield of integrated circuit elements because defects occur in the surface layer when a crystal is processed into a substrate to form a substrate. However, its reduction is extremely important in the production of silicon single crystals.

As described above, this OSF is caused by oxygen, but the amount of the silicon wafer intentionally contaminated with metal is larger than that of the other, so that the metal present in the silicon is a catalyst. Functioning like
In recent years it has become clear that this is one of the reasons.

The present inventors have hitherto overlooked in the step of pulling a single crystal by the Czochralski method,
It was found that the contamination of the single crystal during the growth was caused by the trace amount of metal from the parts inside the apparatus at high temperature. That is, in the past, the behavior of such a component in the apparatus with respect to an extremely small amount of impurities has never been considered for single crystal defects, particularly OSF. Of course, in order to prevent impurities from being taken into the single crystal during growth as much as possible, there was a device to keep the single crystal in a fresh atmosphere by constantly flowing an inert gas such as argon in the apparatus. It has not been attempted to control the oxygen concentration in the single crystal, and thus even the defects, by utilizing the gas pressure balance between various parts in the apparatus.

Reference number = P911200002
Page (4/8)

Under the circumstances, the present invention prevents a gaseous metal or a metal oxide from adhering to a single crystal or being mixed in a melt during pulling. Therefore, the purpose is to accurately control the oxygen concentration in the pulled single crystal.

That is, the present invention relates to a single crystal pulling apparatus by the pulling method, particularly the Czochralski method, one end of which is fixed to the inner wall of the pulling apparatus chamber above the crucible, and the surrounding surface of the single crystal surrounds the raw material melt. In the one provided with the cylindrical body whose other end has reached to the vicinity, a detection mechanism for detecting the differential pressure between the gas phase portion inside the cylindrical body and a control mechanism for controlling this differential pressure according to a predetermined program during the growth of the single crystal. It is characterized by having and. It should be noted that a capacitance type pressure measuring element or a semiconductor pressure sensor may be used for the detection unit of the detection mechanism that detects the pressure difference between the gas phase portion inside and outside the cylinder.

Another aspect of the present invention is characterized in that the pressure difference between the gas phase portion inside and outside the cylinder is controlled according to a predetermined program when growing a single crystal.

[0012]

The operation of the present invention will now be described with reference to FIG.
Inside the chamber 200 of the crystal pulling apparatus 100, above the crucible 1
Cylindrical body 4 hanging from the inner wall 2 of the chamber near the melt surface 3
Is equipped with, and detects the pressure inside this cylinder
Device, for example the sensor 5, to detect the pressure outside the cylinder.
Sensor 6 installed on the outer wall of the chamber 200
There is. The single crystal is obtained by pulling up the seed crystal 7 immersed in the melt surface 3.
It is raised from the raw material melt while being gradually pulled up by the pulling mechanism 8.
Be done. In the cylindrical body 4 surrounding the growing single crystal 9,
Always flow a fresh inert gas, for example argon, from above.
Silicon monoxide generated from the melt surface and parts inside the equipment
Guide the volatilized impurities from the crucible out of the crucible and finally
Outside the system through the exhaust port 10
Carry away. As described above, inside and outside the cylindrical body 4,
Detector 5 for detecting the pressure difference between the phase parts 20 and 30 Reference number = P911200002
Page (5/8) , 6 are provided, and the result is controlled centrally outside the lifting device.
Output to the container 40. In the central controller 40,
Pre-programmed value for the differential pressure inside and outside the cylindrical body 4
The signal is controlled by the valve to control the differential pressure.
Output to controller 50. Upon receiving this signal, the valve controller 50
Is an open / close signal for the valve 12 on the gas supply side and the valve 13 on the exhaust side.
To maintain the differential pressure at a preprogrammed value.
Control to Difference between the detectors 5 and 6 and the central controller 40
A detection mechanism is configured by the mechanism that determines the pressure.

Further, in order to constantly discharge a certain amount of silicon monoxide that volatilizes from the melt surface, it is necessary to maintain the argon gas flow pattern and its flow rate constant. When the clearance between the cylinder and the melt surface changes due to the decrease in the melt surface accompanying the pulling of the single crystal, the flow pattern changes and gas retention occurs. This may cause the deposition of volatilized silicon monoxide on the crucible wall.Therefore, the central controller 40 sends a signal from the central controller 40 to the crucible drive device 60 that synchronizes with the decrease of the melt surface so that the clearance becomes constant. To raise the crucible and perform synchronous control.

[0014]

[Embodiment 1] FIG. 1 is a single crystal drawing showing an embodiment of the present invention.
It is a longitudinal cross-sectional view of a lifting device. Reference numeral 25 indicates a heating mechanism
Silicon melted in the crucible 1 by the roller heater 11.
It is a raw material melt. Further, reference numeral 9 indicates the raw material melt 25.
The seed crystal 7 held at the tip of the pulling mechanism 8
It is a single crystal that is growing due to baldness. Around the single crystal
Is the cylinder, the purge tube 4 is the chamber
Driven at the top. Reduce the diameter of the tip of the purge tube.
It reaches the vicinity of the melt surface 3. In the purge tube 4
Introduces argon gas from the supply port 14 at the top of the chamber
To be done. Argon gas descends along the pulled single crystal
Then, turn it over from the tip of the purge tube and
Through the exhaust port 10 at the bottom of the chamber.
Is discharged. And of the gas phase part inside and outside the purge tube
Pressure sensors 5 and 6 which are detectors for detecting pressure,
Located on the top of the purge tube and the chamber wall
It pressure Reference number = P911200002
Page (6/8) The sensors 5 and 6 are of capacitance type and are 4-6.
A high-precision one with a digit measurement accuracy is used. pressure
A pressure sensing element such as a Pirani gauge is used as the measuring element.
However, these elements output for long-term pressure measurement.
Is not constant and has high accuracy as required in the practice of the present invention.
It turned out to be unsuitable for pressure control. Used in the present invention
Another possible pressure sensing element is the strain on the semiconductor.
There is a so-called semiconductor pressure sensor used. In this example
In this case, the capacitance type is used as described above.
Therefore, the precision of pressure control is extremely high, and
Oxygen concentration control can be performed with high accuracy. Pressure sensor
The differential pressure inside and outside the purge tube detected by the
It is input as a signal to the central controller 40 provided outside the
Based on the value, either gas inlet valve 12 or exhaust valve 13
Or change the opening of both to show the differential pressure.
Keep at the programmed value. Also, if necessary
It also controls the top and bottom of the pot to change the gas conductance.
Let

A semiconductor silicon single crystal was pulled by using the pulling apparatus shown in FIG.

First, raw silicon is placed in a crucible 1 of φ16 ″.
40 kg is melted and the seed crystal 7 is immersed in the silicon melt 25 and pulled up. At this time, the purge tube 4, which is a cylindrical body, is positioned several tens of mm above the silicon melt surface. The height of the silicon melt decreases as the single crystal 9 is pulled up. The crucible is raised so as to cancel it, and the distance between the tip of the cylinder and the silicon melt is kept constant. A suitable distance is 10 to 50 mm. Neck of the pulling process,
The taper, the pulling up of the straight body part, etc. are exactly the same as those in the ordinary Czochralski method.

The inert gas used is argon, the pressure of which is 0.5 to 500 mbar., Preferably 1 to 20 mbar.
Argon is introduced from above the purge tube 4, passes through the outer periphery of the silicon single crystal being pulled, and flows between the opening at the lower end of the purge tube and the silicon melt. At this time, evaporative SiO is carried away. Reference number = P911200002
Page (7/8)

In this example, the pressure inside the purge tube of the argon gas was increased according to a predetermined program along with the pulling, and the pressure difference between the inside and outside of the purge tube was also increased as shown in FIG.

FIG. 3 shows the oxygen concentration in the length direction of the silicon single crystal thus pulled up. As is clear from FIG.
When the pressure difference between the inside and outside of the purge tube is increased with the pulling, the oxygen concentration in the pulled single crystal can be made more constant than in the conventional case where the pressure is kept constant.

[0020]

According to the present invention, the oxygen concentration in the pulled single crystal can be kept uniform and constant in the length direction.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a single crystal pulling apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram showing a differential pressure inside and outside a cylindrical body due to pulling of a single crystal in an example of the present invention.

FIG. 3 is a diagram showing an oxygen concentration distribution in the length direction of a silicon single crystal pulled according to the present invention.

[Explanation of symbols]

1 crucible 2 chamber inner wall 3 melt surface 4 cylindrical body (purge tube) 5, 6 pressure sensor 7 seed crystal 8 pulling device reference number = P911200002
Page ( 8/8 ) 9 Single crystal 10 Exhaust port 11 Heater 12, 13 Valve 14 Supply port 20, 30 Gas phase 25 Raw material melt 40 Central controller 100 Pulling device 200 Chamber

[Procedure amendment]

[Submission date] March 27, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Single crystal pulling method and pulling apparatus

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of growing a single crystal by immersing a seed crystal in a raw material melt melted in a crucible and gradually pulling it up. The present invention relates to a technique for preventing contamination of crystals by metals and metal oxides and controlling the concentration of oxygen taken into a single crystal.

[0002]

2. Description of the Related Art Conventionally, for improving the oxygen concentration distribution in the axial direction of a pulled single crystal, for example, Japanese Patent Laid-Open No. 1-1 is known.
Japanese Patent No. 60893 discloses a technique of sequentially increasing the flow rate of an inert gas supplied into a pulling apparatus to prevent a decrease in oxygen concentration in a silicon single crystal due to single crystal growth. Further, in Japanese Unexamined Patent Publication No. HEI 1-160892, the oxygen concentration in the axial direction of the single crystal is made constant by raising the crucible that keeps the clearance between the tip of the reflector and the melt surface to correspond to the pulling of the single crystal. A method of converting to the same is disclosed. However, these documents do not mention the usefulness of gas pressure sensing of an inert gas.

On the other hand, as a measure against impurities taken into a single crystal, for example, Japanese Patent Publication Nos. 57-40119 and 58-1080 disclose an upper flat annular rim protruding from the edge of a crucible and an annular shape. Attached to the rim and inclined downward from the inner edge into a cylindrical shape, or
A cover consisting of a conical tapered connection and a silicon monoxide condensate condensed during pulling or agglomerates that flow into the melt during the crystal pulling It is said that it can be effectively controlled by appropriately adjusting the flow velocity and pressure of the gas.
However, it is known that, in the case where a cylindrical one is provided around such a single crystal, the oxygen concentration in the crystal axis direction is usually drastically reduced as the single crystal is pulled up.

[0004]

High-purity silicon is mainly used for a substrate for manufacturing a semiconductor integrated circuit element. This high-purity silicon is mainly manufactured by the Czochralski method, which is one of the pulling methods. Has been done. Oxygen is solid-dissolved in the crystal pulled by this method, and this oxygen traps (getters) metal impurities mixed in in the manufacturing process of the semiconductor integrated circuit device, and improves the electrical characteristics of the device. .. Since the getter action is extremely sensitive to the oxygen concentration, its control occupies an important position in the technique of pulling a single crystal by the Czochralski method.

The oxygen of the silicon single crystal being pulled is the oxygen eluted from the quartz crucible and taken into the single crystal as it is pulled. Of course, 90% or more of the oxygen eluted from the quartz crucible into the melt is evaporated as silicon monoxide from the surface of the melt.

On the other hand, the demand for higher quality of the silicon single crystal by the Czochralski method is becoming more and more severe with the improvement of the integration degree of the semiconductor integrated circuit device. In particular, oxygen-induced defects (hereinafter referred to as OSFs) caused by oxygen are considered to directly affect the yield of integrated circuit elements because defects occur in the surface layer when a crystal is processed into a substrate to form a substrate. However, its reduction is extremely important in the production of silicon single crystals.

As described above, this OSF is caused by oxygen, but the amount of the silicon wafer intentionally contaminated with metal is larger than that of the other, so that the metal present in the silicon is a catalyst. Functioning like
In recent years it has become clear that this is one of the reasons.

The present inventors have hitherto overlooked in the step of pulling a single crystal by the Czochralski method,
It was found that the contamination of the single crystal during the growth was caused by the trace amount of metal from the parts inside the apparatus at high temperature. That is, in the past, the behavior of such a component in the apparatus with respect to an extremely small amount of impurities has never been considered for single crystal defects, particularly OSF. Of course, in order to prevent impurities from being taken into the single crystal during growth as much as possible, there was a device to keep the single crystal in a fresh atmosphere by constantly flowing an inert gas such as argon in the apparatus. It has not been attempted to control the oxygen concentration in the single crystal, and thus even the defects, by utilizing the gas pressure balance between various parts in the apparatus.

[0009]

Under the circumstances, the present invention prevents a gaseous metal or a metal oxide from adhering to a single crystal or being mixed in a melt during pulling. Therefore, the purpose is to accurately control the oxygen concentration in the pulled single crystal.

That is, the present invention relates to a single crystal pulling apparatus by the pulling method, particularly the Czochralski method, one end of which is fixed to the inner wall of the pulling apparatus chamber above the crucible, and the surrounding surface of the single crystal surrounds the raw material melt. In the one provided with the cylindrical body whose other end has reached to the vicinity, a detection mechanism for detecting the differential pressure between the gas phase portion inside the cylindrical body and a control mechanism for controlling this differential pressure according to a predetermined program during the growth of the single crystal. It is characterized by having and. It should be noted that a capacitance type pressure measuring element or a semiconductor pressure sensor may be used for the detection unit of the detection mechanism that detects the pressure difference between the gas phase portion inside and outside the cylinder.

Another aspect of the present invention is characterized in that the pressure difference between the gas phase portion inside and outside the cylinder is controlled according to a predetermined program when growing a single crystal.

[0012]

The present invention will now be described with reference to FIG. 1. In the chamber 200 of the single crystal pulling apparatus 100, a cylindrical body 4 is hung from a chamber inner wall 2 above the crucible 1 near the melt surface 3.
A detector for detecting the pressure inside the cylindrical body, for example, a sensor 5 and a sensor 6 for detecting the pressure outside the cylindrical body are installed on the outer wall of the chamber 200. The single crystal is grown from the raw material melt while gradually raising the seed crystal 7 immersed in the melt surface 3 by the pulling mechanism 8. In the cylindrical body 4 surrounding the single crystal 9 being grown,
A fresh inert gas such as argon is constantly flown down from above to guide silicon monoxide generated from the melt surface and volatilized impurities from internal parts of the equipment to the outside of the crucible, and finally to the bottom or side of the chamber. It is carried away from the system through the exhaust port 10 provided. As described above, the detectors 5 and 6 for detecting the pressure difference between the gas phase portions 20 and 30 are provided inside and outside the cylindrical body 4, and the result is output to the central controller 40 outside the pulling device. .. The central controller 40 compares the pressure difference between the inside and outside of the cylindrical body 4 with a preprogrammed value at that time, and outputs a signal to the valve controller 50 to control the pressure difference. In response to this signal, the valve controller 50 sends an open / close signal to the valve 12 on the gas supply side and the valve 13 on the exhaust side to control the differential pressure to be maintained at a preprogrammed value. A detection mechanism is composed of the detectors 5 and 6 and a mechanism for determining the differential pressure between the central controller 40.

Further, in order to constantly discharge a certain amount of silicon monoxide that volatilizes from the melt surface, it is necessary to maintain the argon gas flow pattern and its flow rate constant. When the clearance between the cylinder and the melt surface changes due to the decrease in the melt surface accompanying the pulling of the single crystal, the flow pattern changes and gas retention occurs. This may cause the deposition of volatilized silicon monoxide on the crucible wall.Therefore, the central controller 40 sends a signal from the central controller 40 to the crucible drive device 60 that synchronizes with the decrease of the melt surface so that the clearance becomes constant. To raise the crucible and perform synchronous control.

[0014]

Embodiment 1 FIG. 1 is a vertical sectional view of a single crystal pulling apparatus showing an embodiment of the present invention. Reference numeral 25 is a raw material melt of silicon melted in the crucible 1 by the heater 11 which is a heating mechanism. Further, reference numeral 9 is a single crystal growing from the raw material melt 25 under the seed crystal 7 held at the tip of the pulling mechanism 8 by pulling. A purge tube 4, which is a cylindrical body around the single crystal, is driven above the chamber. The tip of the purge tube is reduced in diameter and reaches near the melt surface 3. Argon gas is introduced into the purge tube 4 through the supply port 14 in the upper part of the chamber. The argon gas descends along the pulled single crystal, reverses from the tip of the purge tube, passes through the upper part of the crucible edge, and is finally discharged from the exhaust port 10 provided at the bottom of the chamber. Then, the pressure sensors 5 and 6 which are detectors for detecting the pressure of the gas phase portion inside and outside the purge tube,
It is provided on the upper part of the purge tube and the chamber wall. The pressure sensors 5 and 6 are of capacitance type, and are of high precision having a measurement precision of 4 to 6 digits. As a pressure measuring element, there is a pressure detecting element such as a Pirani gauge, but these elements have an output that is not constant during long-term pressure measurement, and highly accurate pressure control as required for the implementation of the present invention. It turned out to be unsuitable for. Another pressure detecting element that can be used in the present invention is a so-called semiconductor pressure sensor that utilizes the strain of a semiconductor.
In the present embodiment, since the electrostatic capacitance type is adopted as described above, the precision of pressure control is extremely high, and the oxygen concentration in the pulled crystal can be controlled with high precision. The differential pressure inside and outside the purge tube detected by the pressure sensor is input as a signal to the central controller 40 provided outside the pulling device, and based on this value, either the gas introduction valve 12 or the exhaust valve 13, or Both openings are varied to maintain the differential pressure at a pre-programmed value. Further, if necessary, the upper and lower sides of the crucible are also controlled to change the gas conductance.

A semiconductor silicon single crystal was pulled by using the pulling apparatus shown in FIG.

First, raw silicon is placed in a crucible 1 of φ16 ″.
40 kg is melted and the seed crystal 7 is immersed in the silicon melt 25 and pulled up. At this time, the purge tube 4, which is a cylindrical body, is positioned several tens of mm above the silicon melt surface. The height of the silicon melt decreases as the single crystal 9 is pulled up. The crucible is raised so as to cancel it, and the distance between the tip of the cylinder and the silicon melt is kept constant. A suitable distance is 10 to 50 mm. Neck of the pulling process,
The taper, the pulling up of the straight body part, etc. are exactly the same as those in the ordinary Czochralski method.

The inert gas used is argon, the pressure of which is 0.5 to 500 mbar., Preferably 1 to 20 mbar.
Argon is introduced from above the purge tube 4, passes through the outer periphery of the silicon single crystal being pulled, and flows between the opening at the lower end of the purge tube and the silicon melt. At this time, evaporative SiO is carried away.

In this example, the pressure inside the purge tube of the argon gas was increased according to a predetermined program along with the pulling, and the pressure difference between the inside and outside of the purge tube was also increased as shown in FIG.

FIG. 3 shows the oxygen concentration in the length direction of the silicon single crystal thus pulled up. As is clear from FIG.
When the pressure difference between the inside and outside of the purge tube is increased with the pulling, the oxygen concentration in the pulled single crystal can be made more constant than in the conventional case where the pressure is kept constant.

[0020]

According to the present invention, the oxygen concentration in the pulled single crystal can be kept uniform and constant in the length direction.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a single crystal pulling apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram showing a differential pressure inside and outside a cylindrical body due to pulling of a single crystal in an example of the present invention.

FIG. 3 is a diagram showing an oxygen concentration distribution in the length direction of a silicon single crystal pulled according to the present invention.

[Explanation of symbols] 1 crucible 2 chamber inner wall 3 melt surface 4 cylindrical body (purge tube) 5,6 pressure sensor 7 seed crystal 8 pulling device 9 single crystal 10 exhaust port 11 heater 12, 13 valve 14 supply port 20,30 Gas phase 25 Raw material melt 40 Central controller 100 Lifting device 200 Chamber

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 1]

[Figure 3]

Claims (3)

[Claims] 1. A crucible for filling a raw material, a heating mechanism provided around the crucible for melting the raw material, a pulling mechanism for pulling a single crystal by immersing a seed crystal in the molten raw material, and a pulling device chamber above the crucible. One end is fixed to the inner wall, in the single crystal pulling device with a cylindrical body surrounding the periphery of the single crystal pulling region and the other end reaching near the raw material melt filling region, The detection mechanism for detecting the pressure difference and the supply amount of the inert gas into the pulling device and / or the exhaust amount to the outside of the pulling device are controlled based on the detected differential pressure to control the differential pressure to a single crystal. And a control mechanism for controlling according to a predetermined program during the growth of the single crystal pulling apparatus. 2. The single crystal pulling apparatus according to claim 1, wherein the pressure detecting means of the pressure detecting mechanism for the gas phase inside and outside the cylinder is a capacitance type pressure measuring element or a semiconductor pressure sensor. 3. A seed crystal is dipped in a raw material melt dissolved in a crucible and gradually pulled up through a cylindrical body suspended from an inner wall of a pulling apparatus chamber above the crucible so as to surround a single crystal pulling region. A method for pulling a single crystal in which a single crystal is grown under a crystal, wherein the pressure difference between the gas phase outside the cylinder is controlled according to a predetermined program during the growth of the single crystal.