Double-layer crucible and czochralski crystal pulling furnace

Abstract

The utility model discloses a kind of double-layer crucible and czochralski furnace in the field of single crystal furnace, double-layer crucible includes inner layer crucible and outer layer crucible, the gap between the inner layer crucible with the outer layer crucible forms feeding interlayer, the bottom of the feeding interlayer is provided with the through hole being communicated with the inner layer crucible, granular silicon enters the feeding interlayer from the through hole and enters the inner layer crucible to heat;At least one projection is provided in the feeding interlayer, and the projection is used to eliminate the fluctuation generated when granular silicon enters the feeding interlayer.The double-layer crucible provided by the utility model sets projection on the inner wall of feeding interlayer, and the projection can block the granular silicon entering the feeding interlayer, reduce the potential energy of granular silicon falling, and then reduce the fluctuation generated after granular silicon falling, reduce the disturbance to liquid level in the inner layer crucible when granular silicon falling, reduce the breakage rate in the process of pulling crystal.

Description

Technical Field

[0001] This utility model relates to the field of single crystal furnaces, and more particularly to a double-layer crucible and a Czochralski single crystal furnace. Background Technology

[0002] In the continuous Czochralski crystal pulling process, it is necessary to continuously add raw material granular silicon into the crucible. However, during the continuous feeding process, the addition of granular silicon or small-diameter rod-shaped silicon causes fluctuations in the liquid surface and the silicon liquid in the outer crucible. This fluctuations in the silicon liquid in the Czochralski single crystal pulling section are caused by the silicon liquid flow port, resulting in crystal pulling defects or even wire breakage. Utility Model Content

[0003] The purpose of this invention is to provide a double-layer crucible and a Czochralski single crystal furnace. By setting protrusions in the feeding jacket, the disturbance of the liquid surface in the inner crucible when the silicon particles fall is reduced, thereby reducing the breakage rate during the crystal pulling process.

[0004] To solve the above technical problems, the following technical solution is adopted: In a first aspect, this utility model provides a double-layer crucible, including an inner crucible and an outer crucible. The gap between the inner crucible and the outer crucible forms a feeding jacket. The bottom of the feeding jacket is provided with a through hole communicating with the inner crucible. After the particle silicon enters the feeding jacket, it enters the inner crucible through the through hole for heating. The feeding interlayer has at least one protrusion, which is used to eliminate the fluctuations generated when particulate silicon enters the feeding interlayer.

[0005] Optionally, when the number of protrusions in the feeding interlayer is greater than 1, the protrusions are arranged crosswise within the feeding interlayer.

[0006] Optionally, the protrusion is disposed on the outer wall of the inner crucible or the inner wall of the outer crucible, the protrusion is disposed along the circumference of the inner or outer crucible, and the shape of the protrusion is triangular, arc-shaped, or rectangular. Secondly, this utility model provides a Czochralski single crystal furnace, including the double-layer crucible described in the first aspect, and further including a furnace body and a silicon material feeding device. The double-layer crucible is installed inside the furnace body, and a heating device for heating the double-layer crucible is installed inside the furnace body. The silicon material feeding device is provided with a feeding pipe, and the feeding port of the feeding pipe extends into the furnace body at the opening of the feeding jacket. The granular silicon in the silicon material feeding device enters the feeding jacket from the feeding port. The feeding pipe is provided with a valve for controlling the conveying of the granular silicon.

[0007] Optionally, the heating device includes a graphite heating element disposed below the double-layer crucible and a heater disposed on the side of the double-layer crucible. One end of the heater is connected to a heating electrode at the bottom of the furnace body. The heating electrode is disposed through the bottom of the furnace body and connected to a power source. The graphite heating element is located between the double-layer crucible and the tray. The tray is connected to one end of a drag rod, and the other end of the drag rod is disposed through the bottom of the furnace body.

[0008] Optionally, a flow guide tube is provided directly above the double-layer crucible, and an inverted flow guide hood is provided on the outer side of the flow guide tube. The flow guide tube is located at the inner top of the furnace body. A stretching device for stretching and forming granular silicon after heating in the double-layer crucible is provided above the flow guide tube. An inert gas inlet is provided on the stretching device, and the inert gas inlet is connected to a container containing inert gas through a pipe. An inert gas intake port is provided at the bottom side of the furnace body. The inert gas intake port is connected to a negative pressure device to extract the inert gas inside the furnace body.

[0009] Optionally, the inner sidewall of the furnace body is provided with an insulation layer to reduce heat loss.

[0010] Optionally, the inner bottom of the furnace body is provided with a reflective layer to reduce heat loss.

[0011] Optionally, the protrusion is located between the discharge port of the discharge pipe and the through hole.

[0012] Compared with the prior art, the beneficial effects achieved by this utility model are as follows: 1. The double-layer crucible provided by this utility model has protrusions on the inner wall of the feeding jacket. The protrusions can block the silicon particles entering the feeding jacket, reduce the potential energy of the falling silicon particles, thereby reducing the fluctuations caused by the falling silicon particles, reducing the disturbance of the liquid surface in the inner crucible when the silicon particles fall, and reducing the breakage rate during the crystal pulling process.

[0013] 2. The double-layer crucible provided by this utility model, when several protrusions are set, the protrusions are arranged in a cross pattern, which can further reduce the disturbance of the liquid surface in the inner crucible when the silicon particles fall, and the structure is simple. Attached Figure Description

[0014] Figure 1 This is a cross-sectional structural diagram of the device in an embodiment of this utility model.

[0015] Explanation of reference numerals in the attached figures: 1. Furnace body; 2. Double-layer crucible; 3. Graphite heating element; 4. Tray; 5. Trailing rod; 6. Flow guide tube; 7. Inverted flow guide hood; 8. Silicon material feeding device; 9. Stretching device; 10. Inert gas inlet; 11. Insulation layer; 12. Reflective layer; 13. Heater; 14. Inert gas intake port; 15. Protrusion; 16. Heating electrode; 17. Feeding pipe; 18. Feeding port; 201. Outer crucible; 202. Inner crucible cylinder; 203. Feeding jacket; 204. Through hole. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use.

[0017] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0018] Example 1

[0019] This embodiment provides a double-layer crucible, including an inner crucible 202 and an outer crucible 201. A feeding jacket 203 is formed between the inner crucible 202 and the outer crucible 201. The outer wall of the inner crucible 202 and the inner wall of the outer crucible 201 form the inner wall of the feeding jacket 203. Through holes 204 are provided at the bottom of the feeding jacket 203 and on the side wall of the inner crucible 202. A protrusion 15 is provided on the inner wall of the feeding jacket 203. The double-layer crucible 2 described in this embodiment, as shown... Figure 1 As shown, there are two protrusions 15. One protrusion 15 is located on the outer wall of the inner crucible 202, and the other protrusion 15 is located on the inner wall of the outer crucible 201. The two protrusions 15 are arranged in a cross pattern.

[0020] like Figure 1 As shown, the inner crucible 202 and the outer crucible 201 are cylindrical structures. A protrusion 15 is arranged on one circumference of the inner crucible 202 or the outer crucible 201, and a through-hole is arranged on one circumference of the inner crucible 202. Openings are provided at the top of the feeding jacket 203 and the inner crucible 202. Particle silicon enters through the opening in the feeding jacket 203, melts into molten silicon within the jacket, and then enters the inner liner crucible through the through-hole 204 at the bottom.

[0021] The space within the feeding jacket 203 is divided into multiple spaces by the protrusions 15. After the silicon particles enter from the opening, they pass through the protrusions 15 in sequence, which can reduce their own potential energy. This reduces or eliminates the fluctuation of the silicon liquid caused by the impact energy of the silicon particles when they come into contact with the surface of the silicon liquid inside the feeding jacket 203 and fall to the bottom of the silicon liquid inside the feeding jacket 203. This avoids the impact on the heated silicon liquid in the inner crucible 202 and reduces the breakage rate or defective products of the liquid in the inner crucible 202 during the crystal pulling process.

[0022] The double-layer crucible 2 provided in this embodiment has cross-arranged protrusions 15 on the feeding jacket 203. When the silicon particles pass through the feeding jacket 203, they are blocked by the protrusions 15, reducing their own potential energy. This reduces the impact of the fluctuations generated by the silicon particles on the liquid silicon in the crucible and improves the yield.

[0023] Example 2

[0024] This embodiment provides a Czochralski single crystal furnace based on Embodiment 1, and also includes a furnace body 1 and a silicon material feeding device 8. The double-layer crucible 2 described in Embodiment 1 is installed inside the furnace body 1, and the silicon material feeding device 8 is provided outside the furnace body 1. The silicon material feeding device 8 extends into the furnace body 1 through a feeding pipe 17. The feeding port 18 of the feeding pipe 17 is located at the end of the pipe inside the furnace body 1, which is located at the opening of the feeding jacket 203. Particle silicon enters the feeding jacket 203 through the pipe. A valve is also provided on the pipe to control the amount of particle silicon conveyed.

[0025] A graphite heating element 3 is positioned below the double-layered crucible 2, and a tray 4 is positioned below the graphite heating element 3. A support rod 5 is positioned below the tray 4, supporting and moving the tray 4 to a height that positions the double-layered crucible 2 in the center of the furnace body 1. The other end of the support rod 5 passes through the bottom of the furnace body 1. A heater 13 is also positioned around the outer periphery of the double-layered crucible 2. The heater 13 has a cylindrical structure, similar to the double-layered crucible 2, and is arranged around the outer periphery of the double-layered crucible 2 to uniformly heat it. The heater 13 is connected to a heating electrode 16, which passes through the bottom of the furnace body 1 and is connected to a power source outside the furnace body 1.

[0026] A guide tube 6 is positioned directly above the double-layer crucible 2, at the bottom inner part of the furnace body 1. An inverted guide shroud 7 is positioned around the outer periphery of the guide tube 6's open end. A stretching device 9 is positioned above the guide tube 6, used for stretching the liquid silicon heated in the inner crucible 202. An inert gas inlet 10 is located on the stretching device 9, connected via a pipe to a container holding inert gas. The inert gas enters the stretching device 9 through the inert gas inlet 10, then flows through the guide tube 6 into the furnace body 1. The guide tube 6 guides the incoming inert gas. The inverted guide shroud 7 on the outer periphery of the guide tube 6 also guides the inert gas entering the furnace body 1 towards the inner crucible 202, reducing upward movement and allowing the inert gas to act on the surface of the stretched part, carrying away volatile substances from the surface. An inert gas intake port 14 is provided on the lower side of the furnace body 1. The inert gas intake port 14 is connected to a negative pressure device through a pipe to discharge the inert gas inside the furnace body 1 outside the furnace body 1.

[0027] An insulation layer 11 is arranged on the inner wall of the furnace body 1 to reduce heat loss inside the furnace body 1. A reflective layer 12 is provided at the bottom of the furnace body 1 to reflect heat radiation and reduce heat loss.

[0028] In use, granular silicon is located in the silicon material feeding device 8. The granular silicon enters the feeding jacket 203 from the feeding port 18 of the feeding pipe 17 on the silicon material feeding device 8. There is at least one protrusion above the through hole 204 and below the feeding port 18 of the feeding pipe 17. The granular silicon is further heated and melted in the feeding jacket 203. The granular silicon is obstructed by the protrusion 15 in the feeding jacket 203. After falling into the feeding jacket 203 and melting into molten silicon at the bottom of the feeding jacket 203, the molten silicon enters the inner crucible 202 through the through hole 204 at the bottom to continue melting. The stretching device 9 stretches the molten liquid silicon into shape. At this time, inert gas enters from the inert gas inlet 10, passes through the stretching device 9 and comes into contact with the surface of the stretched part in the stretching device 9, carrying away the volatiles on the stretched part into the furnace body 1, and then exits from the inert gas suction port 14 at the bottom of the furnace body 1.

[0029] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A double-layered crucible, characterized in that, It includes an inner crucible and an outer crucible. The gap between the inner crucible and the outer crucible forms a feeding jacket. The bottom of the feeding jacket is provided with a through hole that communicates with the inner crucible. After the particle silicon enters the feeding jacket, it enters the inner crucible through the through hole for heating. The feeding interlayer has at least one protrusion, which is used to eliminate the fluctuations generated when the particulate silicon enters the feeding interlayer.

2. The double-layered crucible according to claim 1, characterized in that, When the number of protrusions in the feeding interlayer is greater than 1, the protrusions are arranged crosswise within the feeding interlayer.

3. The double-layered crucible according to claim 1, characterized in that, The protrusion is disposed on the outer wall of the inner crucible or the inner wall of the outer crucible, and the protrusion is disposed along the circumference of the inner or outer crucible. The shape of the protrusion is triangular, arc-shaped or rectangular.

4. A Czochralski single crystal furnace, characterized in that, The device includes the double-layer crucible as described in any one of claims 1-3, and further includes a furnace body and a silicon material feeding device. The double-layer crucible is installed inside the furnace body, and a heating device for heating the double-layer crucible is installed inside the furnace body. The silicon material feeding device is provided with a feeding pipe, and the feeding port of the feeding pipe extends into the furnace body at the opening of the feeding jacket. The granular silicon in the silicon material feeding device enters the feeding jacket from the feeding port. The feeding pipe is provided with a valve for controlling the conveying of the granular silicon.

5. The Czochralski single crystal furnace according to claim 4, characterized in that, The heating device includes a graphite heating element disposed below the double-layer crucible and a heater disposed on the side of the double-layer crucible. One end of the heater is connected to a heating electrode at the bottom of the furnace body. The heating electrode is disposed through the bottom of the furnace body and connected to a power source. The graphite heating element is located between the double-layer crucible and the tray. The tray is connected to one end of a drag rod. The other end of the drag rod is disposed through the bottom of the furnace body.

6. The Czochralski single crystal furnace according to claim 4, characterized in that, A flow guide tube is provided directly above the double-layer crucible, and an inverted flow guide hood is provided on the outside of the flow guide tube. The flow guide tube is located at the inner top of the furnace body. A stretching device for stretching and forming granular silicon heated in the double-layer crucible is provided above the flow guide tube. An inert gas inlet is provided on the stretching device, and the inert gas inlet is connected to a container containing inert gas through a pipe. An inert gas intake port is provided at the bottom side of the furnace body. The inert gas intake port is connected to a negative pressure device to extract the inert gas inside the furnace body.

7. The Czochralski single crystal furnace according to claim 4, characterized in that, The inner side wall of the furnace is provided with an insulation layer to reduce heat loss.

8. The Czochralski single crystal furnace according to claim 4, characterized in that, The bottom of the furnace body is provided with a reflective layer to reduce heat loss.

9. The Czochralski single crystal furnace according to claim 4, characterized in that, The protrusion is located between the discharge port of the discharge pipe and the through hole.

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