A flow guide for a single crystal furnace

Abstract

The utility model discloses a flow guide cylinder for single crystal furnace, including flow guide cylinder body, flow guide cylinder body, its characterized in that: the outer wall of flow guide cylinder body is vertical peripheral surface, the inner wall of flow guide cylinder body is the inclined peripheral surface of upper narrow lower wide, and the thickness of the lateral wall of flow guide cylinder body thickens from bottom to top, the inner chamber of flow guide cylinder body is the frustum of cone structure of upper narrow lower wide, and the bottom outer wall of flow guide cylinder body converges to the center of air current inlet through the inner converging circular surface, is equipped with the flow guide groove on the bottom side inner wall of flow guide cylinder body, the flow guide groove is the longitudinal groove body perpendicular to horizontal plane, and the flow guide groove is shallow and wide strip structure, and the groove depth of flow guide groove gradually becomes shallow from bottom to top, and the lateral wall of flow guide cylinder body is the composite layer structure, and the lateral wall includes heat preservation outer layer, middle transition layer and high strength inner layer. The utility model has the advantages of air current optimization, heat field accurate control, crystal growth quality promotion.

Description

Technical Field

[0001] This utility model relates to the field of flow guiding technology for single crystal furnaces, specifically a flow guiding tube for single crystal furnaces. Background Technology

[0002] In the field of monocrystalline silicon growth, the flow guide tube, as a core component of the hot zone system of a monocrystalline furnace, directly affects the flow state of argon gas and the crystal growth environment. Existing flow guide tubes mostly employ vertical or simple conical inner wall structures. Such designs have significant drawbacks in terms of gas dynamics: when argon gas enters the flow guide tube from the bottom, the traditional right-angle transition structure easily generates severe turbulence and eddies in the gas flow turning region, leading to turbulent flow fields on the melt surface. Simultaneously, the uniform wall thickness of the tube structure makes it difficult to match the axial temperature gradient distribution within the monocrystalline furnace, causing a low-speed gas flow zone near the crystal growth interface, weakening impurity carrying efficiency; while a high-speed gas flow forms on the melt surface, causing shear disturbance to the free surface of the silicon melt. This uneven gas flow distribution not only disrupts the stability of the solid-liquid interface and increases the risk of oxygen and carbon impurities entering the crystal, but also induces lattice defects, ultimately leading to a decrease in the yield of monocrystalline rods. Utility Model Content

[0003] The purpose of this invention is to provide a flow guide tube for a single crystal furnace, which has the advantages of optimized airflow, precise control of the thermal field, and improved crystal growth quality, thus solving the problems in the prior art.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A flow guide tube for a single crystal furnace includes a flow guide tube body. The outer wall of the flow guide tube body is a vertical circumferential surface, and the inner wall of the flow guide tube body is an inclined circumferential surface that is narrower at the top and wider at the bottom. The side wall thickness of the flow guide tube body increases from bottom to top. The inner cavity of the flow guide tube body has a frustum-shaped structure that is narrower at the top and wider at the bottom. The bottom outer wall of the flow guide tube body converges towards the center of the airflow inlet through an inwardly tapering arc. A flow guide groove is formed on the bottom inner wall of the flow guide tube body. The flow guide groove is a longitudinal groove perpendicular to the horizontal plane and has a shallow and wide strip-shaped structure. The depth of the flow guide groove gradually decreases from bottom to top. The side wall of the flow guide tube body has a composite layer structure, including an outer heat-insulating layer, a middle transition layer, and a high-strength inner layer.

[0006] Preferably, the thickness of the high-strength inner layer is 20-50mm, and the thickness of the thermal insulation outer layer is 15-35mm.

[0007] Preferably, the number of the flow guide grooves is 6-8 and they are evenly distributed, and the width of the flow guide grooves is 10±0.5mm.

[0008] Preferably, the depth of the guide channel gradually changes linearly from 5mm at the bottom to 0.5mm at the top.

[0009] Preferably, the extension direction of the guide channel is parallel to the axis of the guide cylinder body.

[0010] Preferably, the radius of the inner arc surface is 50-80mm.

[0011] Preferably, the bottom wall thickness of the sidewall of the guide tube body is 8-12mm, and the top wall thickness of the sidewall of the guide tube body is 15-25mm.

[0012] Preferably, the angle between the inner wall surface and the ground is 85°±1°.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] 1. The thickness of the side wall of the guide tube body of this utility model increases from bottom to top. The thin wall at the bottom reduces thermal resistance and promotes the conduction of heat from the molten crucible to the tube wall, thus strengthening the cooling intensity of the crystal growth interface. The thick wall at the top increases heat capacity, reduces heat loss, and concentrates heat in the crystal pulling area, forming a steep axial temperature gradient that matches the temperature decay trend of the single crystal furnace and reduces thermal stress deformation. The inner cavity is a frustoconical shape that is narrow at the top and wide at the bottom, which accelerates the argon gas flow near the crystal growth interface and enhances the impurity carrying efficiency. At the same time, it forms a low-speed zone on the surface of the melt, improving the stability of the liquid surface and reducing crystal defects.

[0015] 2. The bottom outer wall of this utility model converges towards the airflow inlet with an inward arc of 50-80mm radius, optimizing the gas flow path, making the airflow direction smoother, reducing eddy generation, and minimizing disturbance to the molten material. The inner wall is provided with 6-8 longitudinal guide grooves, with the groove depth linearly changing from 5mm at the bottom to 0.5mm at the top. The deep groove at the bottom captures high-speed airflow and reduces turbulent kinetic energy, while the shallow groove at the top maintains the stability of the airflow boundary layer, forming a uniform axial upward flow and reducing shear disturbance to the molten liquid surface. The side wall consists of an insulating outer layer, a middle transition layer, and a high-strength inner layer. The insulating outer layer reduces radial heat loss; the high-strength inner layer maintains structural stability and heat conduction efficiency; and the transition layer buffers differences in thermal expansion, optimizes the heat transfer path, and improves the uniformity of the thermal field. Attached Figure Description

[0016] Figure 1 This is an isometric view of the overall structure of this utility model;

[0017] Figure 2 This is a side wall structure diagram of the overall structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the guide channel of this utility model.

[0019] In the diagram: 1. Guide tube body; 11. Outer wall; 12. Inner wall; 13. Inwardly curved surface; 4. Inner cavity; 2. Airflow inlet; 3. Guide groove; 5. Middle transition layer; 6. High-strength inner layer; 7. Thermal insulation outer layer. Detailed Implementation

[0020] The technical solutions of the present utility model 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 utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] To address the issues of airflow disturbance and thermal stress deformation in existing technologies, the following technical solution is proposed. Please refer to [link / reference needed]. Figure 1-3 ;

[0022] A flow guide tube for a single crystal furnace includes a flow guide tube body 1. The outer wall 11 of the flow guide tube body 1 is a vertical circumferential surface, and the inner wall 12 of the flow guide tube body 1 is an inclined circumferential surface that is narrower at the top and wider at the bottom. The angle between the inner wall 12 and the ground is 85°±1°. Therefore, the side wall thickness of the flow guide tube body 1 increases from bottom to top. The inner cavity 4 of the flow guide tube body 1 has a frustum-shaped structure that is narrower at the top and wider at the bottom. The narrower-at-the-top and wider-at-the-bottom inner cavity 4 accelerates the argon gas flow rate near the crystal growth interface, enhancing impurity carrying capacity. At the same time, it forms a low-speed zone on the melt surface, improving the stability of the liquid surface.

[0023] The bottom of the sidewall is close to the melt and has a wall thickness of 8-12 mm, while the top of the sidewall is close to the crystal growth interface and has a wall thickness of 15-25 mm. The thin bottom wall reduces thermal resistance, promotes heat conduction from the molten zone of the crucible to the wall of the main body of the flow tube, and enhances the cooling intensity of the crystal growth interface. The thick top wall increases heat capacity, reduces heat loss, and concentrates heat in the crystal pulling area, forming a steeper axial temperature gradient. The thick-top, thin-bottom structure matches the temperature decay trend from top to bottom in a single crystal furnace, reducing thermal stress deformation.

[0024] The bottom outer wall 11 converges towards the center of the airflow inlet 2 through the inward arc surface 13, so that the outer circumference of the guide tube body 1 transitions from the upper vertical surface to the lower inward arc surface with an arc radius of 50-80mm. This optimizes the gas flow outside the guide tube body 1. When the gas in the guide tube body 1 enters the airflow inlet 2 from top to bottom, it then flows upward in the internal cavity of the guide tube body 1, making the airflow turn more gently at the inlet 2 to reduce the disturbance of the airflow to the raw material and reduce eddies.

[0025] A guide groove 3 is provided on the inner wall 12 of the bottom side of the guide tube body 1 to guide the flow direction of the airflow. The guide groove 3 is a longitudinal groove perpendicular to the horizontal plane. The extension direction of the groove is parallel to the axis of the guide tube body 1. The guide groove 3 has a shallow and wide strip structure. The depth of the guide groove 3 gradually decreases from bottom to top. There are 6-8 guide grooves 3 evenly distributed. The width of the guide groove 3 is 10±0.5mm. The depth of the groove gradually changes linearly from 5mm at the bottom to 0.5mm at the top. The deep groove area at the bottom captures high-speed airflow and reduces local turbulent kinetic energy. The shallow groove area at the top maintains the stability of the airflow boundary layer and avoids streamline separation. The airflow velocity increases in the vertical direction to form a uniform axial upward flow and reduce the shear disturbance of the melt surface. The sidewall of the guide tube body 1 has a composite layer structure, which includes an outer heat-insulating layer 7, a middle transition layer 5, and a high-strength inner layer 6. The outer heat-insulating layer 7 reduces radial heat loss, the middle transition layer 5 buffers the thermal expansion difference between the inner and outer layers, and optimizes the heat transfer between the inner and outer layers. The high-strength inner layer 6 is the core of the main body's load-bearing and heat conduction, maintaining structural stability. The thickness of the high-strength inner layer 6 is 20-50mm, the thickness of the outer heat-insulating layer 7 is 15-35mm, and the thickness of the middle transition layer 5 depends on the specific production process. The outer heat-insulating layer 7 is made of ceramic fiber composite material or high-density graphite felt, the high-strength inner layer 6 is made of static pressure graphite or carbon composite material, and the middle transition layer 5 is made of specific metal foil or coating.

[0026] Working Principle: The working principle of the guide tube body 1 is based on a dual mechanism of gas flow optimization and thermal field control. Argon gas first enters from the bottom gas flow inlet 2, and achieves a gentle deflection through the inward-curving arc surface 13 at the bottom of the outer wall 11, reducing gas flow disturbance and eddy generation. After deflection, the gas flow flows upward along the inner cavity 4 of the guide tube. This inner cavity 4 has a frustum-shaped structure that is narrow at the top and wide at the bottom, which accelerates the gas flow near the crystal growth interface to enhance impurity carrying, while forming a low-speed zone on the melt surface to improve liquid surface stability. The guide groove 3 further optimizes the gas flow distribution. The deep groove region captures high-speed gas flow to reduce turbulence, while the shallow groove region maintains boundary layer stability, ultimately forming a uniform axial upward flow and reducing shear disturbance of the melt surface.

[0027] Thermal management is achieved through a wall thickness gradient and a composite layer structure. The thin bottom wall reduces thermal resistance, promotes heat conduction from the molten crucible to the cylinder wall, and enhances the cooling intensity of the crystal growth interface. The thick top wall increases heat capacity, reduces heat loss, and concentrates heat in the crystal pulling region, forming a steep axial temperature gradient. This thick-top, thin-bottom structure matches the temperature decay trend from top to bottom in a single crystal furnace, reducing thermal stress deformation.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A flow guide tube for a single crystal furnace, comprising a flow guide tube body (1), characterized in that: The outer wall (11) of the guide tube body (1) is a vertical circumferential surface, the inner wall (12) of the guide tube body (1) is an inclined circumferential surface that is narrow at the top and wide at the bottom, the side wall thickness of the guide tube body (1) increases from bottom to top, the inner cavity (4) of the guide tube body (1) is a frustum-shaped structure that is narrow at the top and wide at the bottom, the bottom outer wall (11) of the guide tube body (1) converges towards the center of the airflow inlet (2) through the inward arc surface (13), the bottom inner wall (12) of the guide tube body (1) is provided with a guide groove (3), the guide groove (3) is a longitudinal groove that is perpendicular to the horizontal plane, the guide groove (3) is a shallow and wide strip structure, the groove depth of the guide groove (3) gradually becomes shallower from bottom to top, the side wall of the guide tube body (1) is a composite layer structure, the side wall includes a heat insulation outer layer (7), a middle transition layer (5) and a high-strength inner layer (6).

2. The guide tube for a single crystal furnace according to claim 1, characterized in that, The thickness of the high-strength inner layer (6) is 20-50 mm, and the thickness of the heat-insulating outer layer (7) is 15-35 mm.

3. A flow guide tube for a single crystal furnace according to claim 2, characterized in that, The number of the flow guide grooves (3) is 6-8 and they are evenly distributed. The width of the flow guide grooves (3) is 10±0.5mm.

4. A flow guide tube for a single crystal furnace according to claim 3, characterized in that, The depth of the guide groove (3) gradually changes linearly from 5 mm at the bottom to 0.5 mm at the top.

5. A flow guide tube for a single crystal furnace according to claim 4, characterized in that, The extension direction of the guide groove (3) is parallel to the axis of the guide tube body (1).

6. A flow guide tube for a single crystal furnace according to claim 5, characterized in that, The radius of the inner arc surface (13) is 50-80mm.

7. A flow guide tube for a single crystal furnace according to claim 6, characterized in that, The bottom wall thickness of the guide tube body (1) is 8-12mm, and the top wall thickness of the guide tube body (1) is 15-25mm.

8. A flow guide tube for a single crystal furnace according to claim 7, characterized in that, The angle between the inner wall (12) and the ground is 85°±1°.

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