Single crystal furnace

Abstract

The utility model relates to a single crystal furnace which comprises a furnace body, a furnace cover, and a heating part, a crucible, a guide cylinder and a heat preservation cylinder which are arranged in the furnace body, a heat preservation cover is arranged at the top end of the heat preservation cylinder, the heating part is arranged on the periphery of the crucible, and a gap is formed between the heating part and the crucible; the guide cylinder is arranged above the crucible in a lifting manner; wherein the single crystal furnace further comprises a heat insulation part, and the heat insulation part is annular, is arranged on the periphery of the guide cylinder in a lifting manner and is positioned below the heat preservation cover. According to the single crystal furnace, in the polycrystalline silicon melting stage, the heat insulation ring is located at a high position, and the influence on the melting stage is reduced; in the monocrystalline silicon drawing stage, the heat insulation ring can descend to the position between the crucible and the heating part, heat radiation of the heating part to the crucible can be reduced through the heat insulation part, the crystallization process is promoted, and the effect of increasing the crystal drawing speed is achieved.

Description

Technical Field

[0001] This utility model relates to the field of single crystal silicon technology, and in particular to a single crystal furnace. Background Technology

[0002] With the rapid development of the photovoltaic industry and the continuous expansion of production capacity, competitive pressure has intensified. Saving costs and increasing production capacity is a survival issue faced by every company. At present, one of the most effective ways to increase production capacity is to increase the speed of monocrystalline silicon pulling and save the pulling time of monocrystalline silicon rods. Therefore, a monocrystalline furnace with low cost and simple structure is needed to increase the pulling speed. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model provides a single crystal furnace that can increase the pulling speed of single crystal silicon rods.

[0004] To achieve the above objectives, this utility model provides a single crystal furnace, including a furnace body, a furnace cover, and a heating section, a crucible, a flow guide tube, and a heat insulation tube disposed within the furnace body. A heat insulation cover is provided at the top of the heat insulation tube. The heating section is disposed around the crucible and has a gap with the crucible. The flow guide tube is vertically and flexibly disposed above the crucible. The single crystal furnace also includes a heat insulation section, which is annular and vertically and flexibly disposed around the flow guide tube and below the heat insulation cover.

[0005] Furthermore, the inner diameter of the heat insulation part is larger than the outer diameter of the crucible, and the outer diameter of the heat insulation part is smaller than the inner diameter of the heating part.

[0006] Furthermore, a reflective coating is provided on the side wall of the heat insulation part away from the guide tube.

[0007] Furthermore, when the heat insulation part is in the highest position, the top surface of the heat insulation part abuts against the lower surface of the heat insulation cover, and the bottom end of the heat insulation part is flush with or above the bottom end of the guide tube; when the heat insulation part is in the lowest position, the top end of the heat insulation part is above the top end of the crucible, and the bottom end of the heat insulation part is below the top end of the crucible and located between the crucible and the heating part.

[0008] Furthermore, it also includes a first lifting part and a first driving device. The furnace cover is provided with a first through hole. The first lifting part passes through the first through hole, one end of which is connected to the heat insulation part, and the other end of which is connected to the first driving device provided outside the furnace body.

[0009] Furthermore, the heat insulation portion includes a heat insulation ring and an extension extending radially from the top of the heat insulation ring toward the central axis, and the first lifting portion is connected to the extension.

[0010] Furthermore, it also includes a second lifting part and a second driving device. The furnace cover is provided with a second through hole. One end of the second lifting part passes through the second through hole and is connected to the guide tube, and the other end is connected to the second driving device provided outside the furnace body.

[0011] Furthermore, the single crystal furnace includes two first lifting parts arranged opposite to each other, and the furnace cover is provided with two first through holes that are opposite to each other.

[0012] Furthermore, the single crystal furnace includes two second lifting sections arranged opposite to each other, and the furnace cover is provided with two second through holes that are opposite to each other.

[0013] Furthermore, the two first through holes and the two second through holes are arranged alternately and evenly distributed along the circumference of the furnace cover.

[0014] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art:

[0015] In the single-crystal furnace, the heat insulation section is ring-shaped and is vertically adjustable, positioned around the flow guide tube and below the insulation cover. During the polycrystalline silicon preparation stage, the heat insulation ring is at a high position, reducing its impact on the preparation stage. During the single-crystal silicon pulling stage, the heat insulation ring can be lowered to between the crucible and the heating section. The heat insulation section reduces heat radiation from the heating section to the crucible, promoting the crystallization process and thus increasing the crystal pulling speed. This embodiment achieves the effect of increasing the crystal pulling speed simply by setting a vertically adjustable flow guide tube and reducing heat radiation. The structure is simple, the production cost is low, and it is beneficial for improving enterprise efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the single crystal furnace material preparation stage of this utility model;

[0018] Figure 2 This is a schematic diagram of the single crystal furnace welding and crystal pulling stages of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure of the heat insulation ring of this utility model during its descent.

[0020] Figure 4 This is a schematic diagram of the structure of the heat insulation ring at the bottom of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of the heat insulation part and the lifting part of this utility model;

[0022] Figure 6 This is a schematic diagram of the structure of the furnace cover of this utility model.

[0023] Explanation of reference numerals in the accompanying drawings: Insulation section - 100; Lifting section - 110; Extension section - 120; Insulation ring - 130; Furnace body - 200; Heating section - 300; Crucible - 400; Flow guide tube - 500; Furnace cover - 600; First through hole - 610; Second through hole - 620; Insulation cylinder - 700; Insulation cover - 800. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0025] Example 1

[0026] Reference Figures 1-6 The present invention provides a single crystal furnace, comprising a furnace body 200, a furnace cover 600, and a heating part 300, a crucible 400, a flow guide cylinder 500, a heat insulation cylinder 700, and a heat insulation part 100 disposed within the furnace body 200. The heat insulation cylinder 700 is provided with a heat insulation cover 800 at its top. The heating part 300 and the crucible 400 are disposed within the heat insulation cylinder 700, wherein the heat insulation cylinder 700 serves to maintain heat. The heating part 300 is disposed around the crucible 400, and there is a gap between the heating part 300 and the crucible 400, wherein the heating part 300 serves to heat.

[0027] The flow guide tube 500 is vertically and vertically positioned above the crucible 400. The flow guide tube 500 has a highest position and a lowest position. When the flow guide tube 500 is in its lowest position, the outer flange at the top of the flow guide tube 500 is engaged with the upper surface of the insulation cover 800. The lower opening of the flow guide tube 500 is closest to the silicon liquid surface. At this position, on the one hand, the flow guide tube 500 can guide the argon gas flow from the single crystal furnace, promoting the removal of oxygen from the silicon liquid surface by the argon gas and reducing the oxygen content of the silicon single crystal; on the other hand... The water-cooling device inside the guide tube 500 can cool the silicon liquid surface to achieve crystallization. When the guide tube 500 is at its highest position, the top outer flange of the guide tube 500 is higher than the heat preservation cover 800 and closer to the furnace cover 600 compared to the lowest position. At this time, the lower opening of the guide tube 500 is the farthest from the silicon liquid surface. The silicon material in the crucible 400 melts into a silicon solution under the action of the heating part 300. The guide tube 500 is at its highest position, which reduces the impact on the silicon melting process.

[0028] The heat insulation part 100 is annular and is vertically and vertically disposed around the outer periphery of the guide tube and below the insulation cover 800. The heat insulation part 100 has a highest position and a lowest position. When the heat insulation part 100 is in the highest position, the upper surface of the top of the heat insulation part 100 abuts against the lower surface of the insulation cover 800, and the bottom of the heat insulation part 100 is flush with or above the bottom of the guide tube 500. At this time, the influence of the heat insulation part 100 on the pulling process can be reduced. When the heat insulation part 100 is in the lowest position, the bottom of the heat insulation part 100 is below the bottom of the guide tube 500 and above the top of the crucible 400. That is to say, the heat insulation part 100 can at least correspond to the silicon liquid surface. The heat insulation part 100 can insulate the silicon liquid surface during the crystallization process, reduce the heat radiation of the heating part 300 to the silicon liquid surface, thereby accelerating crystallization and increasing the pulling speed.

[0029] Furthermore, the inner diameter of the heat insulation part 100 is larger than the outer diameter of the crucible 400, and the outer diameter of the heat insulation part 100 is smaller than the inner diameter of the heating part 300. That is, after the heat insulation part 100 is lowered, it can be located between the crucible 400 and the heating part 300. Specifically, when the heat insulation part 100 is in its lowest position, the bottom end of the heat insulation part 100 is located below the top end of the crucible 400 and between the crucible 400 and the heating part 300, thereby separating the silicon liquid surface inside the crucible 400 from the heating part 300, thereby reducing the heat radiation from the heating part 300 to the silicon liquid surface.

[0030] It should be further noted that the heat insulation part 100 can be made of graphite. Graphite has excellent high temperature resistance, chemical stability, corrosion resistance, and heat insulation properties. Graphite has a melting point of 3850±50℃, a boiling point of 4250℃, a small coefficient of thermal expansion, and its strength doubles at 2000℃. Therefore, in a single crystal furnace, the heat insulation part 100 not only remains unaffected and achieves its heat insulation effect in the high-temperature single crystal furnace, but also maintains material stability during the multiple chemical reactions in the operation of the single crystal furnace, allowing for repeated use. Furthermore, graphite also has high hardness and strength, making the heat insulation part 100 less prone to deformation after repeated use in high-temperature environments and easy to clean.

[0031] It should be noted that, in order to effectively avoid the risk of sparking, a safe distance is maintained between the heat insulation part 100 and the heating part 300 and the crucible 400. Preferably, the distance between the outer diameter of the heat insulation part 100 and the heating part 300 is greater than 15mm, and the distance between the inner diameter of the heat insulation part 100 and the crucible 400 is greater than 5mm. This ensures the safe use of the heating part 300 and effectively avoids the safety risks caused by the heat insulation part 100 rubbing against the crucible 400.

[0032] In one embodiment, a reflective coating is provided on the side wall of the heat insulation part 100 away from the guide tube 500, that is, the heat insulation coating is provided on the side wall opposite to the heating part 300, so that the reflective coating can reflect heat radiation and further reduce heat radiation. The reflective coating can be selected from heat radiation coating, heat reflective material, heat insulation reflective coating, etc., which have heat insulation and temperature insulation functions and can isolate heat transfer.

[0033] In one embodiment, refer to Figure 1 The single crystal furnace also includes a first lifting part 110 and a first driving device (not shown in the figure). The first driving device drives the first lifting part 110 to move up and down. A first through hole 610 is provided on the furnace cover 600. One end of the first lifting part 110 extends downward and passes through the first through hole 610 to connect with the heat insulation part 100, and the other end is connected to the first driving device outside the furnace body 200. In this embodiment, the furnace cover 600 is located on the top of the furnace body 200, and the lifting part 110 is a vertical rod connected to the top of the heat insulation part 100. The first driving device can drive the lifting part 110 and thus drive the heat insulation part 100 to move in the vertical direction. The first driving device is a drive motor, which can accurately control the lifting height of the lifting part 110 at each stage of the operation of the single crystal furnace, and also control the lifting speed. In actual application, while ensuring that the heat insulation part 100 can be lifted and lowered smoothly, the lifting part 110 can be set as one or more.

[0034] In one embodiment, refer to Figure 5The heat insulation part 100 includes a heat insulation ring 130 and an extension 120 extending radially from the top of the heat insulation ring 130 toward the central axis. The lifting part 110 is connected to the extension 120 and then to the heat insulation part 100. In the embodiment, the extension 120 is a horizontal extension component and the lifting part 110 is a vertical rod. The lifting part 110 can pass through the extension and be connected to the heat insulation part 100 by bolts, etc., which is convenient for disassembly and use. The bolts can be carbon carbon bolts, which have the characteristics of high temperature resistance and corrosion resistance, and can remain stable during the operation of the single crystal furnace.

[0035] In one embodiment, the furnace cover 600 is provided with a second through hole 620. One end of the second lifting part passes through the second through hole 620 and is connected to the guide tube 500, and the other end is connected to the second drive device provided outside the furnace body 200. The guide tube 500 is lifted and lowered by the second drive device and the second lifting part. The second drive device is a controllable drive motor.

[0036] In one embodiment, refer to Figure 6 The single crystal furnace includes two first lifting parts 110 arranged opposite to each other, and two first through holes 610 arranged opposite to each other on the furnace cover 600. The two first lifting parts 110 are connected to the heat insulation part 100 to ensure the stability of the lifting of the heat insulation part 100.

[0037] In one embodiment, refer to Figure 6 The single crystal furnace includes two second lifting parts arranged opposite to each other. The furnace cover 600 is provided with two second through holes 620 that are opposite to each other. The two second lifting parts are connected to the guide tube 500 to ensure the stability of the lifting of the guide tube 500.

[0038] In one embodiment, refer to Figure 6 Two first through holes 610 and two second through holes 620 are arranged alternately and evenly distributed along the circumference of the furnace cover 600 to ensure that the movement between the first lifting part 110 driving the heat insulation part 100 and the second lifting part driving the guide tube 500 does not affect each other.

[0039] The working principle of this single crystal furnace is as follows: The single crystal pulling process includes: the material preparation stage, the welding and crystal pulling stage, the shoulder forming and shoulder expansion stage, the constant diameter stage, and the finishing stage. In the material preparation stage, to accelerate the melting of the silicon material, such as... Figure 1 As shown, the guide tube 500 and the heat insulation part 100 are located at the highest position. During the welding and crystal pulling stages, as... Figure 2 As shown, the guide tube 500 descends to its lowest position, while the heat insulation part 100 is at its highest position. The guide tube 500, through its guiding effect, reduces the oxygen content in the silicon crystals formed by ground crystallization, thereby improving the crystallization quality. During the shoulder-turning and shoulder-forming processes, as... Figure 3 As shown and Figure 4As shown, the heat insulation section 100 descends to its lowest position. The heat insulation section 100 separates the silicon liquid surface from the heating section 300, reducing heat radiation from the heat insulation section 100 to the silicon liquid surface, accelerating crystallization, and increasing the pulling speed. In the constant diameter stage, as... Figure 4 and Figure 5 As shown, as the silicon solution crystallizes into a silicon single crystal rod, the amount of silicon solution decreases and the crucible rises. By providing a liftable heat insulation section 100, it can be lowered during the pulling process to reduce the heat radiation of the heating section 300 to the silicon solution and increase the pulling speed. In other stages, it can be raised to the highest position to reduce the impact on the melting, welding, and crystal pulling stages.

[0040] This embodiment achieves increased crystal pulling speed simply by adding a liftable heat insulation ring inside the single crystal furnace. During the polycrystalline silicon preparation stage, the heat insulation ring is positioned high, minimizing its impact on the preparation process. During the single crystal pulling stage, the heat insulation ring can be lowered between the crucible and the heating element. This heat insulation reduces heat radiation from the heating element to the crucible, promoting the crystallization process. This embodiment achieves increased crystal pulling speed simply by using a liftable guide tube and minimizing heat radiation; its simple structure and low production cost contribute to improved enterprise efficiency.

[0041] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A single crystal furnace, characterized in that, The furnace includes a furnace body (200), a furnace cover (600), and a heating element (300), a crucible (400), a flow guide tube (500), and a heat preservation tube (700) disposed within the furnace body (200). The heat preservation tube (700) is provided with a heat preservation cover (800) at its top. The heating element (300) is disposed around the crucible (400) and has a gap with the crucible (400). The flow guide tube (500) is vertically and vertically disposed above the crucible (400). The single crystal furnace also includes a heat insulation part (100), which is annular and is vertically and vertically disposed around the flow guide cylinder (500) and below the heat insulation cover (800).

2. The single crystal furnace according to claim 1, characterized in that, The inner diameter of the heat insulation part (100) is larger than the outer diameter of the crucible (400), and the outer diameter of the heat insulation part (100) is smaller than the inner diameter of the heating part (300).

3. The single crystal furnace according to claim 1, characterized in that, The heat insulation part (100) has a reflective coating on the side wall away from the guide tube (500).

4. The single crystal furnace according to claim 1, characterized in that, When the heat insulation part (100) is in the highest position, the top surface of the heat insulation part (100) abuts against the lower surface of the heat insulation cover (800), and the bottom end of the heat insulation part (100) is flush with or above the bottom end of the guide tube (500); when the heat insulation part (100) is in the lowest position, the top end of the heat insulation part (100) is above the top end of the crucible (400), and the bottom end of the heat insulation part (100) is below the top end of the crucible (400) and between the crucible (400) and the heating part (300).

5. The single crystal furnace according to claim 1, characterized in that, It also includes a first lifting part (110) and a first driving device. The furnace cover (600) is provided with a first through hole (610). The first lifting part (110) passes through the first through hole (610), one end of which is connected to the heat insulation part (100), and the other end is connected to the first driving device provided outside the furnace body (200).

6. The single crystal furnace according to claim 5, characterized in that, The heat insulation part (100) includes a heat insulation ring (130) and an extension (120) extending radially from the top of the heat insulation ring (130) toward the central axis, and the first lifting part (110) is connected to the extension (120).

7. The single crystal furnace according to claim 6, characterized in that, It also includes a second lifting part and a second driving device. The furnace cover (600) is provided with a second through hole (620). One end of the second lifting part passes through the second through hole (620) and is connected to the guide tube (500), and the other end is connected to the second driving device provided outside the furnace body (200).

8. The single crystal furnace according to claim 7, characterized in that, The single crystal furnace includes two first lifting parts (110) arranged opposite to each other, and the furnace cover (600) is provided with two first through holes (610) that are opposite to each other.

9. The single crystal furnace according to claim 8, characterized in that, The single crystal furnace includes two second lifting parts arranged opposite to each other, and the furnace cover (600) is provided with two second through holes (620) that are opposite to each other.

10. The single crystal furnace according to claim 9, characterized in that, Two first through holes (610) and two second through holes (620) are arranged alternately and are evenly distributed along the circumference of the furnace cover (600).

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