KR101202616B1 - Single crystal silicon ingot - Google Patents

Abstract

PURPOSE: A single crystal silicon ingot is provided to increase a minority carrier lifetime by making resistance and electric conductance uniform. CONSTITUTION: The oxygen content of an ingot is less than 3×10^16 atoms/cm^3. The carbon content of the ingot is 1×10^11 to 6×10^15 atoms/cm^3. A minority carrier lifetime of a p-type ingot is 100 to 15,000 us. A minority carrier lifetime of an n-type ingot is 1,000 to 50,000 us. The diameter(D) of the ingot is 10 to 50 cm. The axial length(AL) of the ingot is 50 to 500 cm.

Description

Monocrystalline Silicon Ingot {SINGLE CRYSTAL SILICON INGOT}

The present invention relates to a single crystal silicon ingot, and more particularly, to a single crystal silicon ingot manufactured by the Continuous CZochralski (CCZ) method.

Single crystal silicon is actually used as the base material for all semiconductor and photovoltaic cell components, which are made of perfect single crystal with high purity. The method conventionally used for such preparation is Czochralski method.

Typical apparatuses used by the Czochralski method include a chamber, a crucible installed inside the chamber, a susceptor for supporting the crucible, a pedestal for supporting the susceptor and raising, lowering and rotating the crucible, and an inner wall of the chamber. Heater installed in the heat shield, the heat shield and the heat shield and the insulator to minimize the discharge of heat to the outside of the chamber is configured. In addition, an inert gas such as argon gas is supplied into the chamber to remove impurities.

In the Czochralski method, seed crystals of single crystal silicon are brought into contact with the surface of the silicon melt and gradually raised to form a cylindrical boule of single crystal silicon. The fire is rotated in a direction opposite to the rotational direction of the crucible to increase the mixing efficiency of the dopant in the silicon melt, thereby making the concentration distribution of the dopant in the single crystal silicon ingot uniform, thereby making the quality characteristics of the single crystal silicon ingot uniform.

The inventors' patents disclosed in connection with the continuous growth Czochralski method (CCZ) include U.S. Patent No. 5,314,667, U.S. Patent No.5580171, U.S. Patent Publication No. 2007/0056504, and the like.

U.S. Patent No. 5,314,667, "Method and apparatus for single crystal silicon production," carried out an improved method for the growth of silicon single crystals, a continuous growth type in which polysilicon particles and dopants are continuously supplied and ingots are continuously grown. The Czochralski method (CCZ) was specified. According to this, a method of growing a single crystal silicon ingot designed to efficiently control thermal balance by dividing the crucible into a raw material supply region and a crystal growth region is specified.

In addition, US Pat. No. 5,558171, "Solids mixing, storing and conveying system for use with a furnace for single crystal silicon production," provides a homogeneous mixture of polysilicon particles and dopant in feeding the polysilicon particles into the crucible. Proposed means for this.

In addition, in the Republic of Korea Patent Publication No. 2006-0128033 with respect to the single crystal silicon ingot manufacturing apparatus has a feature of providing to the crucible after making the molten state in providing the molten polysilicon to the crucible by separately preliminary chamber. However, in the patent method, the oxygen impurity due to the melting of SiO ₂ in the pre-melting chamber increases in the ingot content, it is difficult to control the uniform concentration of the dopant, so that the quality deviation of the ingot occurs. The uniformity of electrical resistivity of the ingot produced in this patent is at least 10%.

Therefore, it has been desired to develop a single crystal silicon ingot having a high uniformity of electrical resistance and a low content of impurities and having excellent quality.

An object of the present invention to solve the above problems is to provide a product in which the quality of the silicon ingot is uniform in the axial direction and the radial direction.

Another object of the present invention is to adjust the oxygen and carbon content of the ingot, the resistance and electrical conductivity of the ingot are uniform in the axial direction and the radial direction.

Still another object of the present invention is to provide a silicon ingot of excellent quality using a silicon ingot manufacturing apparatus capable of supplying polysilicon and a dopant constantly.

In order to achieve the above object, the present invention provides a single crystal silicon ingot manufactured by Czochralski method, wherein the ingot has a diameter (D) of 10 to 50 cm and an axial length (AL) of 50 to 500cm, uniform resistance, provides a single crystal silicon ingot characterized by Axial Resistivity Gradient (ARG) 0.01 ~ 7%, Radial Resistivity Gradient (RRG) 0.01 ~ 5%.

The present invention also provides a single crystal silicon ingot, wherein the oxygen content of the ingot is 3 × 10 ¹⁶ atoms / cm 3 or less.

The present invention also provides a single crystal silicon ingot, wherein the carbon content of the ingot is 1 × 10 ¹¹ to 6 × 10 ¹⁵ atoms / cm 3.

100 to 15,000 microseconds when the minimum carrier life time of the ingot is p-type (micro second), 1,000 to 50,000 microseconds when the n-type (n-type) It provides a single crystal silicon ingot characterized in that.

In another aspect, the present invention comprises a supply unit for supplying the raw material into the chamber for producing a single crystal silicon ingot, the supply unit to supply polysilicon, dopant or polysilicon and dopant, a hopper-type reservoir; A connector for moving polysilicon under the reservoir; A discharge pipe which is integrally communicated with the connection pipe and formed of an opening pipe; And it provides a single crystal silicon ingot manufactured using a device consisting of a screw conveyor for quantitative discharge of polysilicon in the discharge pipe.

In another aspect, the present invention provides a single crystal silicon ingot manufactured using a device comprising a polysilicon supply device, a dopant supply device and a mixer for mixing the polysilicon and the dopant in a predetermined ratio.

In addition, the present invention is the mixer is composed of a first plate and a second plate, the first plate is a funnel shape to form a hole in the center apex, the second plate located below the first plate is a plurality of radial in the center Provided is a single crystal silicon ingot manufactured using a device constructed by sequentially circularly arranging two V-shaped sectors.

In another aspect, the present invention provides a single crystal silicon ingot manufactured by using a device further comprising a transfer tube capable of moving a predetermined amount of polysilicon or dopant discharged through the screw conveyor to the mixer.

In addition, the present invention forms an external storage tank on the outside of the reservoir is closed and sealed to the outside, the single crystal is manufactured by using a device in which a portion of the connection pipe, the discharge pipe, screw conveyor and the delivery pipe is located in the lower portion of the storage tank. Provides silicon ingots.

The present invention also provides a single crystal silicon ingot manufactured using the apparatus, characterized in that the discharge pipe is horizontal to the ground or smaller than the angle of repose.

In another aspect, the present invention provides a single crystal silicon ingot manufactured by using a device that can control the polysilicon feed rate by adjusting the rotational speed of the screw by the screw conveyor receives the driving force of the motor.

In addition, the present invention is the material of the reservoir, the connection pipe and the discharge pipe is made of any one of silicon, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), quartz (SiO ₂ ), silicon, silicon carbide (SiC), It provides a single crystal silicon ingot manufactured using a device characterized in that the coating or lined with any one of silicon nitride (Si ₃ N ₄ ), quartz (SiO ₂ ).

In addition, the present invention is characterized in that the argon gas is supplied into the chamber, the argon gas is supplied from the top and bottom of the chamber is discharged from the upper side of the chamber, the argon gas supplied from the bottom of the crucible is a susceptor And between the heater and between the heater and the heat shield to provide a single crystal silicon ingot manufactured using the device, characterized in that discharged through the outlet located below the upper heat shield.

In the single crystal silicon ingot according to the present invention, the supply of polysilicon and the dopant is uniformly made in the crucible of the silicon ingot manufacturing apparatus, thereby making it possible to manufacture a silicon ingot having excellent quality.

In addition, the single crystal silicon ingot according to the present invention has an overall uniform quality, resistivity and electrical conductivity as a whole, can control the oxygen and carbon content, and has the effect of extending the minimum carrier life time.

1 shows a schematic diagram of a single crystal silicon ingot according to one embodiment of the invention.
Figure 2 shows a schematic cross-sectional view of a device for producing a single crystal silicon ingot according to an embodiment of the present invention.
3 is a perspective view of a second plate of the mixer in the apparatus for producing a single crystal silicon ingot.
Figure 4 shows a cross-sectional view of the polysilicon supply apparatus in the apparatus for producing a silicon ingot according to an embodiment of the present invention.
5 is a perspective view showing a schematic shape formed integrally of the connection pipe and the discharge pipe in the polysilicon supply apparatus according to an embodiment of the present invention.
Figure 6 shows the flow of argon gas in a cross-sectional view of the apparatus for producing a silicon ingot according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

The terms " about ", " substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation to or in the numerical value of the manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

As used herein, "an angle of repose" refers to the angle of the maximum limit of the frictional force, the greater the angle of repose, the greater the force of gravity than the friction force, so the force of gravity moves the material downward.

In the manufacture of single crystal silicon ingots, the present inventors have conducted research to produce products with higher quality than conventional silicon ingots, and have uniform Axial Resistivity Gradient (ARG) and Radial Resistivity Gradient (RRG), and have oxygen content and carbon content. This significantly lower ingot was produced.

Hereinafter, a single crystal silicon ingot manufacturing apparatus according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described.

1 shows a schematic diagram of a single crystal silicon ingot according to one embodiment of the invention.

Referring to FIG. 1, a single crystal silicon ingot may be represented by an axial length (AL) and a diameter (Diameter (D)).

In the single crystal silicon ingot manufactured by the continuous growth type Czochralski method, the single crystal silicon ingot according to the present invention has a diameter (D) of 10 to 50 cm and an axial length (AL) of 50 to 500 cm. Axial Resistivity Gradient (ARG) is 0.01 ~ 7%, Radial Resistivity Gradient (RRG) is 0.01 ~ 5% with uniform resistance, oxygen content is 3 × 10 ¹⁶ atoms / cm 3 or less, and carbon content is 1 × 10 A single crystal silicon ingot is characterized by being ¹¹ to 6 x 10 ¹⁵ atoms / cm 3. In addition, the minimum carrier life time of the ingot is 100 to 15,000 microseconds for the p-type and 1,000 to 50,000 microns for the n-type. Second), a single crystal silicon ingot is provided.

Figure 2 is a schematic cross-sectional view showing an ingot manufacturing apparatus for producing a single crystal silicon ingot according to an embodiment of the present invention. The single crystal silicon ingot of the present invention can be applied without limitation to a single crystal silicon ingot manufacturing apparatus that the crucible does not rotate or rotate.

Referring to Figure 2, the ingot is made while the crucible is rotated in the silicon ingot manufacturing apparatus according to the continuous growth type Czochralski method (CCZ) according to an embodiment of the present invention, the chamber; A crucible installed inside the chamber; A supply unit for supplying a raw material to the crucible; Inside the crucible is an internal crucible for easy mixing of the polysilicon melt and the dopant; A susceptor surrounding the crucible; A heater for heating the crucible; And a heat shield and an insulator for preventing heat from being emitted from the heater, wherein the supply unit includes a polysilicon supply device, a dopant supply device, and a mixer for mixing the polysilicon and the dopant at a predetermined ratio.

The chamber includes a feeder such that a supply is connected through the feeder so that the polysilicon and the dopant can be supplied to the crucible. The polysilicon supply device and the dopant supply which constantly supply the polysilicon and the dopant Apparatus, consisting of a feeder consisting of a mixer for mixing the polysilicon and the dopant in a certain ratio to supply the polysilicon and the dopant to the crucible.

In the process by the continuous growth Czochralski method (CCZ), in order to fill polysilicon into the crucible and to adjust the dopant, it is important to mix the polysilicon and the dopant in a constant ratio. . The dopant is a material added for the electrical resistance of the ingot, and examples thereof include boron (B), phosphorus (P), and antimony (Sb).

The mixer is composed of a first plate and a second plate in a closed cylindrical shape, the first plate is a funnel shape and a central hole is formed at the center apex. When material falls on the first plate, it collects in the central hole of the central vertex and falls down. The polysilicon and the dopant dropped down through the central hole are moved to the second plate 10 located below.

The second plate 10 located below the first plate is configured by sequentially arranging a plurality of V-shaped sectors radially from the center. The V-shaped sector becomes larger in the V-shape from the center to the outside (see FIG. 3).

In the second plate 10, the number of circular arrangements of the V-shaped sectors may vary depending on the size of the mixer, but the number of preferable circular arrangements of the V-shaped sectors is preferably 6-12.

The polysilicon and the dopant collected by the first plate are divided by the V-shaped sectors of the second plate 10, respectively.

In addition, the first plate in the shape of a funnel is sequentially placed below the second plate 10, and the material (polysilicon and dopant) moved from above is divided and collected by the first plate again.

Thus, the first plate and the second plate 10 are sequentially positioned, so that the polysilicon and the dopant are gathered by the first plate and scattered by the second plate 10 so that they are evenly mixed.

The first plate and the second plate 10 are sequentially located, but the first plate is located one more, so that the first plate is located at the top and bottom. The number of laminations of a preferable 1st board is 3-10 pieces, More preferably, it is 3-6 pieces.

The plurality of V-shaped sectors are lowered from the center toward the outside so that the materials brought down to the center by gravity move to the edges. The material moved to the edge again falls to the underlying first plate and is collected back to the center.

By repeating this, the polysilicon and the dopant are evenly mixed.

In addition, the rod 11 is located at the center of the second plate 10, which extends upward and is present in the central hole of the first plate. The thickness of the rod 11 is smaller than the diameter of the central hole of the first plate so that the polysilicon and the dopant may move between the rod 11 and the central hole. The rod is moved downwards with the material (polysilicon and dopant) transferred to the first plate hitting rod 11. The role of the rod 11 is to prevent the material (polysilicon and dopant) descending to the center of the first plate to move to one side by the speed of descending.

On the other hand, in order to quantitatively supply polysilicon and dopant to the mixer, sophisticated work is required. For this, it is important to supply the correct amount to the mixer from the polysilicon feeder and the dopant feeder. To this end, the present invention can supply a fixed amount by having a polysilicon supply device and a dopant supply device.

Figure 4 shows a cross-sectional view of the polysilicon metering device in the silicon ingot manufacturing apparatus according to an embodiment of the present invention.

The polysilicon supply device may be a supply unit by itself and directly connected to a feeder of a silicon ingot manufacturing device to supply polysilicon without the presence of a mixer, and to supply simultaneously with the dopant, as shown in FIG. It may be configured to be supplied to the feeder.

Looking at the polysilicon supply, a hopper-type reservoir; A connector for moving polysilicon under the reservoir; A discharge pipe which is integrally communicated with the connection pipe and formed of an opening pipe; And a screw conveyor for quantitatively discharging polysilicon into the discharge pipe.

The polysilicon supply device includes a reservoir 110, an external reservoir 111, a connection pipe 112, an outlet pipe 113, a screw conveyor 114, a stopper 116, a delivery pipe 117, a support 119 and a pedestal 120 and the like.

The reservoir 110 is not particularly limited in shape but is preferably made of a hopper form. The storage tank 110 is surrounded by an external storage tank 111 and sealed to the outside, and serves to store the polysilicon and supply it to a silicon ingot manufacturing apparatus.

The reservoir 110 is manufactured to a size sufficient to store more than the amount of polysilicon required to manufacture one ingot, or can be additionally supplied in accordance with the ingot production cycle. Therefore, preferably, when manufacturing the ingot in the silicon ingot manufacturing apparatus to supply the polysilicon into the storage tank 110 in advance to store a sufficient amount of polysilicon in the storage tank 110 without the hassle of separately supplying the polysilicon to manufacture the silicon ingot Can be.

In addition, there is a block valve 122 at the lower end of the reservoir 110 to adjust the supply amount of polysilicon.

The polysilicon of the reservoir 110 may be supplied through a supply unit. The supply part is sealed to the outside, and an inert gas may be supplied into the reservoir 110 while the polysilicon is supplied from the polysilicon supply device to the silicon ingot manufacturing device through the supply part, and if necessary, the inert gas may be inert. The gas prevents the ingress of air from the outside.

The connection tube 112 is a tube connecting the polysilicon in the reservoir 110 to be introduced into the silicon ingot manufacturing apparatus, the connection tube 112 may be made of one or more bends. The connecting pipe 112 is formed of one or more bends to prevent the polysilicon in the reservoir 110 from being excessively supplied to prevent it from overflowing through the upper portion of the discharge pipe 113, or a large amount at a time when flowing into the silicon ingot manufacturing apparatus through the delivery pipe 117. This is to prevent the supply. For the same reason, it is preferable that the end of the connector 112 is smaller than the ground or the angle of repose, and the end of the connector 112 is smaller than the ground or the angle of repose, so that the polysilicon from the reservoir 110 to the connector 112. This is to supply a proper amount of oil, but not to supply a large amount at a time. In addition, it is to deliver a certain amount to the discharge pipe 113 irrespective of when polysilicon is stored in a large amount and a small amount in the storage tank 110.

In addition, the amount supplied may be adjusted according to the size of the diameter of the connector 112. The larger the diameter of the connector 112, the larger the amount of polysilicon supply, the smaller the diameter of the connector 112, the smaller the amount of polysilicon supply, so the appropriate supply amount may be adjusted according to the size of the diameter. However, this method alone is difficult to control the exact amount, so more detailed control of the supply amount is required.

The present invention may further include a discharge pipe 113 integrally communicated with the connecting pipe 112, the discharge pipe 113 is preferably made of a U-shaped opening tube. The reason why the discharge pipe 113 is formed as an opening pipe path is to facilitate delivery by the screw conveyor 114 without clogging the polysilicon coming out of the connection pipe 112 into the pipe. In addition, the discharge pipe 113 is formed of a U-shaped opening tube because the load cell 121 does not cause interference when measuring the weight of the polysilicon. The load cell 121 is a device for measuring the weight of polysilicon in the reservoir. If it is in the form of a round tube, the screw 115 is placed in the round tube, and the load cell 121 interferes with the weighing of the screw, so that an accurate measurement cannot be obtained. . In the case of the circular tube shape, the polysilicon granules are sandwiched between the screw 115 and the circular tube, which may affect the rotation of the screw.

The discharge pipe 113 is preferably smaller than the horizontal or the angle of repose to the ground, which is to prevent the over-supply of polysilicon, and to supply a certain amount.

The polysilicon entering the discharge pipe 113 may be constantly moved quantitatively by the screw conveyor 114.

5 is a perspective view showing a schematic shape formed integrally with the connection pipe 112 and the discharge pipe 113 according to an embodiment of the present invention.

The height of the discharge pipe 113 is preferably at least 0.5 times the outer diameter of the connecting pipe 112, and more preferably 0.5 to 0.8 times the outer diameter of the connecting pipe 112. If the height of the outlet tube 113 is less than 0.5 times the outer diameter of the connector 112, then the screw 115 of the screw conveyor 114 may overflow the polysilicon over the outlet tube 113 as it rotates.

Looking specifically at the height of the discharge pipe 113, the discharge pipe 113 is formed integrally with the connecting pipe 112 from the lower portion of the connecting pipe 112 to a height that is 0.5 times the outer diameter of the connecting pipe 112, the upper portion is extended upwards by more than 0.5 times It is desirable to be able to achieve the "U" shape. This can be understood with reference to FIG. 5.

In addition, a stopper 116 may be formed at a boundary between the connection pipe 112 and the discharge pipe 113. The stopper 116, which can be installed in close contact with the end face of the connection pipe 112 at the upper part of the discharge pipe 113, prevents the polysilicon from being excessively moved to the discharge pipe 113 through the connection pipe 112 and adjusts the speed at which the polysilicon is supplied to the discharge pipe 113. have.

The stopper 116 is installed in close contact with the end surface of the connecting pipe 112 to move up and down at the boundary of the connecting pipe 112 and the discharge pipe 113, it is possible to adjust the opening degree of the connecting pipe 112. By adjusting the height of the stopper 116, the amount of polysilicon exiting the discharge pipe 113 can be mechanically controlled. That is, to increase the supply amount of polysilicon, the stopper 116 is moved upward to increase the supply area of the connection pipe 112, and conversely, to reduce the supply amount, the stopper 116 is moved downward to reduce the supply area of the connection pipe 112. By placing the stopper 116 up and down, the amount of polysilicon supplied can be controlled.

In addition, the screw conveyor 114 serves to discharge the polysilicon existing in the discharge pipe 113 by a predetermined amount. The screw conveyor 114 quantitatively supplies polysilicon into the crucible of the silicon ingot manufacturing apparatus at regular intervals. For this means, the screw conveyor 114 may rotate the screw 115 by receiving the driving force of the motor. By adjusting the rotational speed (RPM) of the screw 115, it is possible to control the polysilicon feed rate, it can be finely controlled to supply the polysilicon quantitatively.

Screw 115 of the screw conveyor 114 may be present in the discharge pipe 113, the polysilicon reaching the discharge pipe 113, the polysilicon moves to the delivery pipe 117 by the rotation of the screw 115. The screw 115 is present in the outlet tube 113 and is preferably slightly spaced from the stopper 116 in order to prevent the polysilicon supplied from the connecting tube 112 from being caught between the stopper 116 and the screw 115.

 A certain amount is moved by the rotation of the screw 115 in the space between the screw 115 and the screw 115. The screw 115 is not in contact with the discharge pipe 113, so that the polysilicon is not caught between the screw 115 and the discharge pipe. For this purpose, the distance between the discharge pipe 113 and the screw 115 should be larger than the size of the polysilicon.

If the screw 115 is less than or equal to the size of the polysilicon of the discharge pipe 113 may be a problem that the polysilicon is sandwiched between the screw 115 and the discharge pipe 113 to stop the operation.

In addition, the feed rate of the polysilicon to the ingot manufacturing apparatus may be controlled by adjusting the interval between the screw 115 and the screw 115. If the screw 115 spacing is formed close, a large amount will be supplied, and if the screw 115 spacing is away, a small amount will be supplied.

The screw conveyor 114 may be supplied with power separately from the outside, and the power unit may be installed outside the external reservoir 111 to control the power from the outside. It should be noted that the external reservoir should be sealed to the outside, so that the external air should not come in by the screw conveyor connection. Therefore, a ferrofluid seal may be used as an example in which the external reservoir may be blocked from the outside when the screw conveyor is connected. The ferrofluid seal is a magnetic injected into the gap between the stationary magnet and the rotating shaft. Ferro fluid refers to a non-contact seal that performs sealing by creating a kind of "Liquid O-Ring" by a magnetic flux formed by stationary poles and rotating shafts.

The screw conveyor 114 is formed away from the discharge pipe 113 is connected to the reservoir 110 can be controlled differently from the reservoir 110 and the parts connected thereto.

In addition, the delivery pipe 117 according to an embodiment of the present invention is present in the vertical lower portion of the distal end of the discharge pipe 113, the polysilicon moved to the discharge pipe 113 distal end through the screw 115 is received by gravity when it falls by the transfer pipe 117 Can be delivered into the crucible by

In the present invention, the shape of the delivery tube 117 is not particularly limited and may be formed as a tube having a diameter of sufficient size to accommodate the polysilicon from the discharge tube 113, and made of a tube that can be moved to the crucible in the silicon ingot apparatus. do.

On the other hand, it includes a support 119 that can support and support the lower portion of the reservoir 110, the support 119 is located in the lower portion of the reservoir 110 to support the reservoir 110, and to be balanced. The lower portion of the reservoir 110 forms a funnel shape that decreases in diameter toward the lower portion, and the support 119 surrounds the outside of the funnel shape, which is the lower portion of the reservoir 110, and serves to support and balance the weight of the reservoir 110. do. The support may be attached to the reservoir 110, so that the support 119 is moved according to the weight of the reservoir 110 is spaced apart from the external reservoir 111.

Since the support is separated from the external reservoir, the weight of the support and the reservoir can be measured, but the weight can be measured by the load cell 114. Since the support 120 and the support 120 to support the weight of the reservoir 110 is included, serves to support the weight of the reservoir 110 and the support 119. The load cell 121 is positioned between the lower surface of the support 119 and the contact surface of the pedestal 120, and the load cell 121 measures the weight of the storage tank 110 so that the amount of polysilicon is supplied to check the supply amount of the polysilicon. You can control the amount.

In other words, the difference between the planned supply and the actual supply can be easily identified using the load cell 121. When the weight of the storage 110 decreases rapidly due to supplying more than the planned supply, the polysilicon is oversupplied, so the stopper 116 Can be controlled by adjusting the rotation speed (RPM) of the screw conveyor 114 and moving the stopper 116 upward when the weight of the reservoir 110 decreases slowly, and adjusting the rotation speed of the screw conveyor 114. Can be controlled.

On the other hand, between the external reservoir 111 and the reservoir 110 is closed and sealed to the outside, the lower portion of the reservoir 110 in the outer reservoir 111 may be a portion of the connecting pipe 112, the discharge pipe 113, screw conveyor 114 and the delivery pipe 117. .

In addition, the empty space in which the polysilicon is not filled in the reservoir 110 may be supplied by being filled with an inert gas such as argon gas. The inert gas is supplied to minimize the generation of impurities in the reservoir 110, and polysilicon is discharged to fill the empty space. Only a small amount of the inert gas is supplied into the reservoir 110, and only the amount of polysilicon is discharged into the reservoir 110.

The inert gas may be supplied through a supply pipe 118 to fill an empty space generated while polysilicon is supplied from the polysilicon supply device to the silicon ingot manufacturing apparatus.

The polysilicon metering device supplied to the silicon ingot manufacturing apparatus is used to adjust the polysilicon supply amount by adjusting the diameter of the connector 112, the height of the stopper 116, the rotation speed of the screw 115, and the interval of the screw 115 to adjust the silicon of the desired amount of polysilicon. It can be supplied in an ingot manufacturing apparatus.

In the polysilicon supply device, the material of the reservoir, the connection pipe and the delivery pipe is made of any one of silicon, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), quartz (SiO ₂ ), or silicon, carbide It is preferable to be coated or lined with any one of silicon (SiC), silicon nitride (Si ₃ N ₄ ) and quartz (SiO ₂ ), and the material of the external storage tank may be any one of stainless steel, quartz and carbon steel. Is preferably.

On the other hand, the device for supplying the dopant is also to be constantly supplied by the supply device, the dopant supply device may be formed in the same configuration as the polysilicon supply device described above for the constant supply of the dopant.

Figure 6 shows the flow of argon gas in a cross-sectional view of the silicon ingot production apparatus of the continuous growth type Czochralski method (CCZ) to produce a single crystal silicon ingot according to an embodiment of the present invention.

Referring to FIG. 6, the ingot is manufactured while the crucible is rotated in the single crystal silicon ingot manufacturing apparatus. The crucible 201, the susceptor 202, the heater 203, the heat shield 205, the insulator 204, the pedestal 209, and the shaft 210 are provided. do. The crucible 201, including the susceptor 202, is rotated by the shaft 210, and the single crystal silicon ingot is rotated in a direction opposite to the rotation direction of the shaft 210 to generate a single crystal silicon ingot.

Argon gas entering from the top removes silicon oxide generated from the surface of the melt and discharges it to the top of the chamber, and argon gas from the bottom prevents argon containing silicon oxide from coming into contact with the graphite component in a reverse flow. . To this end, the top and bottom are designed to be sealed and removed through outlet 208 connected to the vacuum pump.

The apparatus of the continuous growth type Czochralski method is connected to a feeder system, and polysilicon and dopant mixed at a predetermined ratio through the feeder 212 are supplied to the crucible 201, and the crucible 201 is enclosed outside the crucible 201. Susceptor 202 is located. The crucible 201 is heated to melt the supplied polysilicon, and a heater 203 is installed around the crucible 201 for heating. The heater 203 serves to melt the polysilicon present in the crucible 201 by applying a power source to heat the crucible 201.

The melting temperature of the polysilicon is about 1410 ° C., which is heated by the heater 203 to melt the polysilicon, and the melted polysilicon enters the inner crucible 211 and grows into a single crystal silicon ingot while gradually cooling below about 1410 ° C.

The heat shield 205 and the insulator 204 insulate the heat emitted from the heater 203 to improve thermal efficiency, and protect the inner wall of the chamber from high temperature radiant heat.

The crucible 201 may generally use quartz (SiO ₂ ), wherein the supplied polysilicon is melted and mixed by the rotation of the crucible 201 and ingot, and the molten silicon is made of monocrystalline silicon ingot in the inner crucible 211. . At this time, the SiO ₂ melted from the crucible 201 and the molten silicon react to form an oxide SiO _x . This reaction is shown below.

SiO ₂ (crucible) + Si (molten silicon) → 2SiO _x ............. (1)

The silicon oxide (SiO _x ) produced by the above reaction prevents the single crystal silicon ingot from crystallizing. That is, silicon oxide (SiO _x ) becomes a gas and evaporates. The evaporated silicon oxide solidifies below 1410 ° C. and adheres to the growing ingot surface to stop crystal growth and stop single crystal growth. In addition, a part of the silicon oxide (SiO _x ) present in the melt flows into the silicon single crystal to form oxygen impurities. In addition, the silicon oxide (SiO _x ) that has been discharged by gasification corrodes the heater 203, the susceptor 202, the heat shield 205, and the insulator 204 to form and react with silicon oxide, thereby becoming SiC.

Therefore, argon gas is used to remove such unnecessary silicon oxide (SiO _x ), and the silicon oxide (SiO _x ) is discharged out of the chamber by supplying the argon gas from the bottom of the silicon manufacturing apparatus.

However, silicon oxide (SiOx) flows through the susceptor 202, the heater 203, the heat shield 150, and the insulator 204 in the process of discharging argon gas. However, when the vacuum outlet 208 is located in the lower part of the chamber, the parts are made of graphite as a material and the silicon oxide (SiOx) reacts as follows to corrode the graphite to release carbon monoxide (CO). Some deteriorate with silicon carbide and lose its function. This scheme is shown below.

C (graphite) + SiOx → CO + SiC ......... (2)

At the same time, the carbon monoxide generated above is absorbed by the silicon melt and flows into the growing ingot and accumulates as carbon impurities.

Therefore, the single crystal silicon ingot manufacturing apparatus and the method according to the present invention is a silicon oxide (SiO _x ) oxide generated in the crucible 201 so that the flow path of argon gas does not pass through the crucible 201, heater 203, heat shield 205, insulator 204. Change to prevent corrosion and deterioration of graphite parts.

To this end, the present invention forms an outlet 208 on the upper side of the chamber to supply argon gas from the upper part of the chamber to remove impurities in the crucible 201, and to supply a portion of the argon gas from the lower part of the crucible 201 to flow upward. Silicon oxide (SiO _x ) generated within 201 was physically prevented from contacting the susceptor 202, the heater 203, the insulator 204 and the heat shield 205.

Argon gas supplied from the top is led through the cone 206 to the top of the crucible 201, which leads to impurities 208 such as silicon oxide generated on the molten silicon surface in the crucible 201. The argon gas minimizes the mixing of impurities in the single crystal silicon ingot manufactured by leading impurities such as silicon oxide to the discharge port 208.

Impurities, such as silicon oxide, together with the argon gas are discharged out through the outlet 208, the outlet 208 is located above the side of the chamber, preferably below the upper heat shield 207. That is, the outlet 208 is preferably located higher than the crucible 201, the outlet 208 is preferably made of a vacuum exhaust pipe. The vacuum exhaust pipe is connected to the chamber and is designed such that argon gas including impurities in the chamber can be easily discharged out of the chamber due to the pressure supplied with the argon gas and the role of the vacuum pump connected to the vacuum exhaust pipe. One or more outlets 208 are preferably formed, and more preferably two to six outlets 208 are formed. Argon gas is efficiently discharged in the above range.

The outlet 208 is located below the top heat shield 207 so that when argon gas is supplied from the top, it does not reverse the path in which argon gas is moved after being led into the crucible 201 by a cone. That is, it rarely occurs to move up the upper heat shield 207 on the upper side of the chamber.

In addition, argon gas is supplied from the lower part of the crucible 201, and argon gas flows between the susceptor 202 and the heater 203 and between the heater 203 and the heat shield to move upwards, thereby causing the silicon oxide (SiO _x ) generated in the crucible 201 to susceptor 202. Therefore, the possibility of contact with the heater 203, the heat shield 205, and the insulator 204 is excluded to prevent deterioration or corrosion of the graphite parts due to the contact reaction.

The argon gas supplied from the lower part is also discharged to the outlet 208 located under the upper heat shield 207, so that the case where the argon gas is moved upward is higher than the cone 206 and the upper heat shield 207.

The amount of argon gas supplied from the upper part of the chamber is preferably supplied so that the volume or mole ratio of the argon gas supplied from the lower part to the upper part is 9: 1 to 3: 2.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

Feeder: 100
Storage tank: 110 External storage tank: 111 Connector: 112
Outlet tube: 113 screw conveyor: 114 screw: 115
Stopper: 116 Delivery pipe: 117 Supply pipe: 118
Support base: 119 Base: 120 Load cell: 121
Monocrystalline Silicon Ingot Manufacturing Equipment: 200
Crucible: 201 Susceptor: 202 Heater: 203
Insulator: 204 Heat Shield: 205 Cone: 206
Upper Heat Shield: 207 Outlet: 208 Pedestal: 209
Shaft: 210 Internal Crucible: 211 Feeder: 212

Claims (13)

In the single crystal silicon ingot manufactured by the Czochralski method,
The ingot has a diameter (D) of 10 to 50 cm, an axial length (AL) of 50 to 500 cm, and a uniform resistivity of Axial Resistivity Gradient (ARG) of 0.01 to 7%, and a radial resistivity gradient. Single crystal silicon ingot, characterized in that (RRG) is 0.01 to 5%.
The method of claim 1,
The ingot has an oxygen content of 3 × 10 ¹⁶ atoms / cm 3 or less.
The method of claim 1,
The ingot has a carbon content of 1 × 10 ¹¹ to 6 × 10 ¹⁵ atoms / cm 3.
The method of claim 1,
The minimum carrier life time of the ingot is 100-15,000 microseconds for p-type and 1,000-50,000 microseconds for n-type. Single crystal silicon ingot, characterized in that.
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