First crucible for growing silicon single crystal through continuous feeding by Czochralski method and material melting and crystal pulling device thereof

Abstract

The invention discloses a first crucible for growing silicon single crystals through continuous feeding by a czochralski method and a material melting and crystal pulling device thereof. The main body of the first crucible is annular on the x-y plane and is provided with one or more z-direction openings and a material groove with an annular or annular notch-shaped cross section on the horizontal plane, a plurality of downward flow dredging channels are arranged below the material groove, and a filtering pore plate is arranged near the joint part of the flow dredging channels and the material groove. The design has the advantages that the heat efficiency of the system is high, the melt crucible and the crystal pulling crucible are adjacent up and down, the thermal resistance of an inner-layer quartz partition wall is eliminated, and the energy consumption is reduced; the oxygen content of molten silicon is low, oxygen volatilization is promoted by optimizing a crucible temperature field, controlling melt convection and expanding a free liquid level, and precise regulation and control are achieved in cooperation with segmented heating; technological parameters are independently adjustable, and the two crucibles are designed in a layered manner, so that mutual interference is small; the crystal pulling stability is high, the large molten silicon liquid level promotes volatilization of impurity particles, the flow dredging channel prolongs the migration path, and the blocking effect of the filtering pore plate effectively inhibits the crystal change defect.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon single crystal preparation, and more specifically, to a first crucible for growing silicon single crystal by continuous feeding in the Czochralski method using granular silicon as raw material, its molten material, and crystal pulling device. Background Art The existing double-layer crucible for growing silicon single crystal by continuous feeding in the Czochralski method using granular silicon as raw material is close to the present invention. The outer layer of the crucible continuously melts the granular silicon material, and conveys the molten silicon through the through holes or gaps at the bottom layer to the inner layer of the crucible, and continuous crystal pulling is realized in the inner layer of the crucible.

[0002] The existing technology has the following deficiencies, which affect the quality and production cost of silicon single crystal: a) Low thermal efficiency. Due to the low thermal conductivity of quartz and the inner quartz partition blocking the effective thermal convection of molten silicon, the outer layer of the crucible forms a thermal shield for the inner layer of the crucible, resulting in a large temperature difference between the inner and outer molten silicon. In order to maintain a suitable temperature for the inner molten silicon, it is necessary to increase the output power of the heater, resulting in low thermal efficiency, high power consumption, and increased product cost. Another existing technology with an independent molten silicon system has the further deficiency of low heating and heat preservation efficiency. As is well known, energy consumption is an important part of the cost of silicon single crystal; b) High oxygen content in molten silicon and difficult to control. Due to the thermal shield formed by the outer layer of the crucible for the inner layer, the temperature of the outer molten silicon is high and the convection is strong, resulting in a large amount of oxygen in the quartz crucible being incorporated into the molten silicon. At the same time, due to the reduction of the surface area of the molten silicon in the inner crucible, it hinders the oxygen in the molten silicon from volatilizing in the form of SiO X and ultimately leads to an increase in the oxygen content of the silicon single crystal; c) Prone to crystal transformation. During the process of pulling silicon single crystal, small silicon dioxide particles will occasionally fall off from the quartz crucible. Under normal circumstances, these particles will volatilize in the form of gas SiO X before floating to the silicon single crystal crystallization interface, and will not affect the normal growth of the silicon single crystal. This is also one of the reasons why the diameter of the crucible is required to reach 2.5 - 3 times the diameter of the crystal in the crystal pulling process. Due to the smaller diameter of the inner layer of the crucible, the probability of these silicon dioxide particles floating to the silicon single crystal crystallization plane increases, which is prone to crystal transformation, terminating the crystal pulling process, reducing production efficiency, and increasing manufacturing cost.

[0003] d) Silicon dust is likely to float during feeding. The feeding end of the existing double-layer crucible is designed to be open. When there is dust in the broken silicon material, it is easy to float onto the surface of the molten silicon and crystal in the inner layer of the quartz crucible. The silicon dust of the silicon material that has not been melted in time is likely to cause the failure of crystal pulling.

[0004] e) Single function, limited to continuous feeding, without other additional functions. For example: the radial temperature distribution and longitudinal temperature gradient distribution in the silicon single crystal ingot cannot be adjusted separately; nor does it have a further function of controlling and reducing oxygen. Summary of the Invention

[0005] The object of the present invention is to provide a first crucible, its molten material and crystal pulling device for continuous feeding and growing silicon single crystal by the Czochralski method using granular silicon as raw material, so as to at least improve one of the above deficiencies. In a first aspect, the present invention provides a first crucible for continuous feeding and growing silicon single crystal by the Czochralski method, characterized in that: the main body of the first crucible has an annular cross-section in the x-y plane, the annular shape includes a quasi-circular ring, a quasi-elliptical ring or a quasi-polygonal ring, the first crucible is provided with one or more z-direction openings and a material groove with an annular or ring-segment shape in the horizontal cross-section, and at least one downward flow-diverting channel is provided below the material groove, and a filter orifice plate is provided near the joint of the flow-diverting channel and the material groove.

[0006] In this application document, the so-called "ring-segment shape" refers to a part on the quasi-circumference of a ring, such as a sector ring and a quasi-sector ring, etc.

[0007] Compared with the prior art, the beneficial effects of the embodiments of the present invention when applied to the molten material and crystal pulling device for continuous feeding and growing silicon single crystal by the Czochralski method in this application document are as follows: a) The system has high thermal efficiency.

[0008] The first crucible for molten material is located above and adjacent to the second crucible for crystal pulling, eliminating the barrier of the inner quartz partition wall in the prior art to the thermal convection and heat conduction of molten silicon. Therefore, the energy consumption in the process of pulling silicon single crystal is low, and the system has high thermal efficiency.

[0009] b) The oxygen content of molten silicon is low and easy to control.

[0010] The melting of silicon and crystal pulling are carried out in the first crucible and the second crucible respectively. The first crucible has a large heating power, and the surface temperature of the crucible and granular silicon is high, but the amount of molten silicon in the first crucible is small, the convection is weak, and the contact area between the molten silicon and the crucible is small. Therefore, less impurity oxygen enters the molten silicon; The liquid level height in the second crucible is low, and the temperature of the molten silicon near the second crucible is low. Therefore, the convection of the molten silicon is weak, and less impurity oxygen enters the molten silicon; The surface area of the free liquid surface of the molten silicon in the second crucible is large, which is conducive to the volatilization of oxygen impurities.

[0011] Therefore, compared with the prior art of double-layer crucible continuous feeding for pulling silicon single crystal, the present invention is easier to control the oxygen content in the silicon single crystal and obtain a silicon single crystal with a lower oxygen content.

[0012] c) The melting of silicon and crystal pulling are regulated separately.

[0013] The silicon melting and crystal pulling are carried out in the first crucible and the second crucible respectively. The two crucibles are at different heights of the heater. The heater is designed in sections, or the first crucible is provided with a separate first heater, and the heating and heat preservation powers can be adjusted respectively. The two are less involved with each other, the process conditions are easy to adjust, and the impurity content is easy to control.

[0014] d) The crystal pulling process is stable and crystal transformation is not likely to occur.

[0015] In the present invention, due to the large free liquid surface area of the molten silicon, during the process of pulling a silicon single crystal, the tiny silicon oxide particles shed from the quartz crucible have a high probability of volatilizing in the form of gas after floating for a certain distance before reaching the crystal boundary of the silicon single crystal, without affecting the normal growth of the silicon single crystal; the probability of the fine particles of the silicon material leaking out from the filter orifice plate is small, and the flow-through path is long. The fine silicon particles are easily melted during the migration process, preventing the normal growth of the silicon single crystal from being affected.

[0016] Furthermore, the outer wall of the inner ring edge of the material tank in the present invention is designed as an air flow guiding surface that is inclined or arc-shaped in the xoz cross-section, with an inclination angle α of 20° to 85° for the inclined line or arc. On the one hand, it is beneficial to the streamline design of the process gas argon, making the working conditions stable and the turbulence small; on the other hand, it provides stable heat reflection and heat preservation near the crystal crystallization interface, reducing the radial temperature gradient near the crystallization interface, making the crystallization interface flat, with small stress and uniform impurity distribution.

[0017] Furthermore, the outer edge of the first crucible is provided with at least one of the structures of lug or flange or boss. It is beneficial to fix the first crucible above the second crucible in various ways to realize the functions of melting materials and transporting molten silicon to the second crucible.

[0018] Preferably, when the first crucible is fixed on the structural member in the furnace cavity, one or more material tank cover plates are annularly distributed at the opening of the material tank of the first crucible.

[0019] Preferably, the material tank cover plate is a porous structure filter screen made of ceramic or quartz materials. The beneficial effect of this material tank cover plate is that when adding materials, it disperses and balances the air pressure inside and outside the material tank, preventing silicon dust from falling with the air flow and causing crystal pulling failure due to not being melted in time.

[0020] Furthermore, for all the flow-through channels, the total arc length of the outer diameter blocking the molten silicon surface in the second crucible is less than 1 / 2 of the inner circumference of the second crucible at this position, so as to reduce the occupation of the molten silicon surface area of the second crucible, thereby facilitating further control of the increase in oxygen content.

[0021] Preferably, the flow-through channels are in a spiral descending shape in the circumferential direction of the second crucible, with a descending angle of γ, and 5° < γ < 75°.

[0022] In this application document, the descent angle γ is defined as the ratio of the distance that a point on the flow-diverting channel descends along the inner wall of the crucible's rotating cylinder surface to the distance it moves on this cylinder surface, and it is the sine of the descent angle γ.

[0023] The flow-diverting channel in a spiral descent shape lengthens the path for the molten silicon to flow from the first crucible to the second crucible, enabling the unmolten silicon particles to have sufficient time to melt. Furthermore, when the flow-diverting channel leads to below the molten silicon liquid level of the second crucible, and at the same time the first crucible is fixed to the structural member in the furnace chamber, the spiral descent setting of the flow-diverting channel, in cooperation with the rotation of the crucible in the crystal pulling process, produces a downward pressing effect on the molten silicon at the edge of the second crucible, which can suppress the intensity of the upward heat convection of the molten silicon at the edge of the second crucible and reduce the oxygen impurities entering the molten silicon; further, the flow-diverting channel, in cooperation with the rotation of the crucible in the crystal pulling process, also has a stirring effect on the molten silicon, making the impurity distribution uniform.

[0024] Multiple flow-diverting channels are inserted into the molten silicon liquid level for the addition and replenishment of molten silicon, which can achieve large-batch continuous feeding. At the same time, being inserted into the molten silicon liquid level is conducive to increasing the mixing uniformity of the newly added molten silicon and the silicon melt, promoting the formation of a symmetric flow field, and reducing the flow rate of the newly added molten silicon, which is beneficial to the stability of the crystal pulling environment.

[0025] Preferably, the material of the first crucible contains silicon nitride (Si3N4) or silicon oxynitride (Si2N2O), and the proportion of nitrogen element in the material of the first crucible is 4% - 40% by weight ratio. Compared with quartz, the materials of silicon nitride (Si3N4) or silicon oxynitride (Si2N2O) have higher strength and softening point, are more adaptable to the higher temperature process conditions during the melting of silicon materials, are more durable, are beneficial for long-term use, and reduce costs.

[0026] In a second aspect, the present invention provides a melting and crystal pulling device for continuously feeding and growing silicon single crystals by the Czochralski method, including: a feeding pipe, a second crucible, a carbon crucible wall, a carbon crucible bottom, a second heater, and a flow guiding and temperature control screen. The aforementioned first crucible is arranged above the second crucible, the first crucible and the second crucible are coaxially arranged, and the vertical distance between the outer bottom of the material groove of the first crucible and the upper edge of the second crucible is less than 150 mm, and this distance includes negative values, that is, the outer bottom of the material groove of the first crucible can be lower than the upper edge of the second crucible.

[0027] In cooperation with the design of the aforementioned first crucible, it has the above-mentioned various beneficial effects.

[0028] The flow guiding and temperature control screen in this application document is used to assist in adjusting the heat dissipation rate of the silicon single crystal in the position where it is located, and it can be designed either for heat preservation or for forced heat dissipation.

[0029] Furthermore, the flow-diverting channel below the material groove leads to below the molten silicon liquid level of the second crucible. The beneficial effects thereof are as follows: a) Some unmolten tiny silicon particles that can pass through the filter orifice plate provided in the first crucible's charging trough will temporarily float on the surface of the molten silicon in the diversion channel, further melt, and avoid directly entering the second crucible to interfere with normal crystal growth. b) The diversion channel extending below the molten silicon level in the second crucible, in conjunction with the rotation of the second crucible, can form a stirring effect on the molten silicon, making the temperature field and the distribution of impurities in the molten silicon uniform. c) The molten silicon flowing into the second crucible enters below the molten silicon level, causing little interference to the molten silicon level and making the crystal pulling process stable.

[0030] Preferably, the lug or flange or boss of the first crucible is connected to the charge and crystal pulling device in at least one of the following ways: a) The first crucible is connected to the second crucible through the lug or flange or boss. During the growth of silicon single crystal, the first crucible and the second crucible rotate synchronously and in the same direction, making the circumferential feeding amount and heating uniform. b) The first crucible is connected to the carbon crucible wall through the lug or flange or boss. During the growth of silicon single crystal, the first crucible and the second crucible rotate synchronously and in the same direction, making the circumferential feeding and heating uniform, and the first crucible is reliably placed. c) The first crucible is connected to the fixed structure in the furnace body through the lug or flange or boss. During the growth of silicon single crystal, the orientation of the first crucible is fixed and does not rotate. In cooperation with the rotation of the second crucible in the crystal pulling process, a stirring effect on the molten silicon can be formed, making the temperature field and the distribution of impurities in the molten silicon uniform.

[0031] Preferably, there is no intermediate partition between the charging trough section of the first crucible and the second heater or the first heater. The first crucible directly receives the thermal radiation of the second heater or the first heater, and higher thermal efficiency and lower impurity carbon pollution can be obtained.

[0032] Preferably, the projection vector direction of the extension direction vector of the diversion channel downward from the charging trough in the x - y plane is the same as the rotation direction of the second crucible. The beneficial effect is that the diversion channel generates a downward pressing effect on the molten silicon at the edge of the second crucible, which can inhibit the intensity of the upward thermal convection of the molten silicon at the edge of the second crucible and reduce the oxygen impurities entering the molten silicon.

[0033] Furthermore, the charge and crystal pulling device has at least one of the following characteristics: a) Both the second crucible and the first crucible are heated by the second heater. The second heater is designed with segmented heating power along the z - direction to give appropriate power distribution to the first crucible and the second crucible. b) The first crucible is heated by a separately provided first heater. The first heater and the second heater cooperate to provide appropriate heating power for the first crucible and the second crucible. c) The relative position between the second crucible and the first crucible, and the relative position between the gas flow guiding surface of the first crucible and the silicon single crystal growth interface are fixed, and the heat transfer conditions are stable. d) The relative position between the flow guiding and temperature controlling screen and the silicon single crystal growth interface is fixed, and the heat transfer conditions are stable.

[0034] The temperature gradient near the crystallization plane of a reasonable silicon single crystal ingot requires as low a radial temperature difference as possible and as high an axial temperature gradient as possible. The former is to obtain a flat crystallization plane, reduce the stress of the silicon single crystal ingot and the non-uniformity of the impurity distribution in the cross-section, and obtain a larger diameter silicon single crystal ingot; the latter is to obtain a higher single crystal growth rate.

[0035] To achieve this purpose, the first crucible of the present invention is closely adjacent to the second crucible. By setting the height, the width and shape of the ring of the first crucible, the reflection of the thermal radiation to the molten silicon and the heat preservation length, heat preservation position and heat preservation intensity near the silicon single crystal growth interface are changed; by adjusting the position of the flow guiding and temperature controlling screen above the first crucible, the effect of forced cooling at the far end of the crystallization interface is adjusted separately. The two can be adjusted separately to achieve the purpose of reducing the radial temperature difference of the silicon single crystal and obtaining a higher axial temperature gradient of the silicon single crystal. The beneficial effects are that the crystallization interface is flat, the stress is small, a silicon single crystal with a larger cross-sectional area can be drawn, the drawing speed is higher, and the energy consumption is reduced. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 Schematic diagram of the first crucible, its molten material and crystal pulling device for growing silicon single crystal by the Czochralski method with continuous feeding provided in Embodiment 1 of the present application; Figure 2 Schematic diagram of the first crucible provided in Embodiment 1; Figure 3 Schematic diagram of the first crucible, its molten material and crystal pulling device for growing silicon single crystal by the Czochralski method with continuous feeding provided in Embodiment 2 of the present application; Figure 4 Schematic diagram of the first crucible provided in Embodiment 2; Figure 5Schematic diagram of a first crucible, its molten material, and a crystal pulling device for growing silicon single crystals by continuous feeding using the Czochralski method provided in Embodiment 3 of the present application; Figure 6 Schematic diagram of the first crucible provided for Embodiment 3; Figure 7 Schematic diagram of a first crucible, its molten material, and a crystal pulling device for growing silicon single crystals by continuous feeding using the Czochralski method provided in Embodiment 4 of the present application; Figure 8 Schematic diagram of the first crucible provided for Embodiment 4; Icons: 100 - device; 108 - first crucible; 1 - carbon crucible bottom; 2 - carbon crucible side; 3 - second crucible; 4 - flow guiding and temperature control screen; 51 - first heater; 52 - second heater; 6 - feed pipe; 71 - granular silicon; 72 - molten silicon; 721 - free surface of molten silicon; 73 - silicon single crystal ingot; 74 - silicon crystal particles; 81 - material tank; 83 - filter orifice plate; 84 - flow diversion channel; 841 - outer inclined wall of the flow diversion channel; 85 - air flow guiding surface; 86 - material tank cover plate; 87 - lug; 88 - flange; 89 - boss. Detailed implementation manners

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0040] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0042] In addition, terms such as "first" and "second" are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0043] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0044] Embodiment 1 As Figure 1 、 Figure 2 shown, this embodiment provides a first crucible 108 for growing silicon single crystal by continuous feeding in the Czochralski method. The main body of the first crucible 108 is circular in cross-section in the x-y plane. The main body is provided with a trough 81 having an opening in the z direction. The trough 81 is annular. Four downward flow-diverting channels 84 are provided below the trough 81. A filter plate 83 is provided at the joint of the flow-diverting channels 84 and the trough 81.

[0045] The outer wall cross-section of the inner ring edge of the trough 81 of the first crucible 108 is an arc-shaped air flow guiding surface 85. The air flow guiding surface 85 includes a section with an inclination angle α of 20° to 85° from bottom to top.

[0046] The bottom of the outer edge of the first crucible 108 is provided with a boss 89 structure for connecting with the second crucible 3.

[0047] The four downward flow-diverting channels 84 of the trough 81 have an outer diameter of 40 mm, and the total arc length at the molten silicon surface in the second crucible 3 blocked by them is much less than 1 / 2 of the inner circumference of the second crucible 3 at this position.

[0048] The material of the first crucible 108 contains Si3N4 or Si2N2O, and the proportion of nitrogen element contained therein is 10% by weight.

[0049] This embodiment also provides a molten material and crystal pulling device 100 for growing silicon single crystal by continuous feeding in the Czochralski method, including: a feeding pipe 6, a second crucible 3, a carbon crucible wall 2, a carbon crucible bottom 1, a second heater 52, a first crucible 108, and a flow guiding and temperature control screen 4. The first crucible 108 and the second crucible 3 are coaxially arranged and share the second heater 52. The boss 89 of the first crucible 108 is placed on the upper edge of the second crucible 3. During the growth of the silicon single crystal, the first crucible 108 and the second crucible 3 rotate synchronously and in the same direction. During the crystal pulling process, as the first crucible 108 rotates, the supplementary granular silicon 71 is continuously added to the trough 81 of the first crucible 108. After melting, it is transported through the flow-diverting channels 84 to below the free liquid surface 721 of the molten silicon in the second crucible 3.

[0050] Compared with the prior art, the beneficial effects of this embodiment: a) High system thermal efficiency. The first crucible 108 for melting the material is placed above the second crucible 3 for crystal pulling, sharing the second heater 52, eliminating the barrier of the inner quartz partition to the thermal convection and conduction of the molten silicon, so the thermal efficiency is relatively high; b) Low oxygen content in the silicon single crystal and easy to control.

[0051] Melting the silicon and crystal pulling are carried out in the first crucible 108 and the second crucible 3 respectively. The heating power density of the first crucible 108 is large, and the surface temperature of the first crucible 108 and the granular silicon 71 is high. However, there is less molten silicon 72 in the first crucible 108, weak convection, and a small contact area between the molten silicon and the crucible. Therefore, less impurity oxygen enters the molten silicon 72; The first crucible 108 contains Si3N4 or Si2N2O with 10% by weight of N element. A higher proportion of Si3N4 or Si2N2O is beneficial to further reduce the oxygen element entering the molten silicon; The liquid level height in the second crucible 3 is low, the temperature of the molten silicon 72 near the second crucible 3 is low, and the convection of the molten silicon 72 is weak. Therefore, less impurity oxygen enters the molten silicon 72; The surface area of the free liquid surface 721 of the molten silicon in the second crucible 3 is large, which is beneficial to the volatilization of oxygen impurities.

[0052] Therefore, compared with the prior art of double-layer crucible continuous feeding for pulling silicon single crystals, it is easier to control the oxygen content in the silicon single crystal in this embodiment, and a silicon single crystal with a lower oxygen content can be obtained.

[0053] c) Melting the silicon and crystal pulling are carried out in the first crucible 108 and the second crucible 3 respectively, and their process environments can be adjusted separately. The connection between crystal pulling and melting is less, and the process is stable.

[0054] d) The crystal pulling process is stable and it is not easy to have crystal transformation. In this embodiment, due to the large area of the free liquid surface 721 of the molten silicon, during the process of pulling the silicon single crystal ingot 73, the tiny silicon oxide particles shed from the first crucible 108 and the second crucible 3 will volatilize in the form of gas after floating a long distance before reaching the silicon single crystal crystallization interface, without affecting the normal growth of the silicon single crystal.

[0055] e) The material of the first crucible 108 is a compound of Si3N4 or Si2N2O material containing 10% by weight of N element. In the high-temperature environment of inert gas, it has higher strength and stability than quartz, is more suitable for the process conditions during silicon material melting, is more durable, is beneficial for long-term use, and reduces costs.

[0056] f) The first crucible 108 has a heat preservation effect near the crystallization interface. Its air flow guiding surface 85 reflects the radiation above the lower silicon surface, which is beneficial to increasing the temperature at the edge of the crystallization interface and reducing the radial temperature difference near the crystallization interface. Combined with the cooling effect of the flow guiding temperature control screen 4 on the upper part of the silicon single crystal ingot 73, the purpose of respectively controlling the radial temperature difference near the crystallization interface and the longitudinal temperature gradient of the silicon crystal is achieved.

[0057] Example 2 This embodiment provides a first crucible 108 for growing silicon single crystals by the Czochralski method with continuous feeding. The same parts as in Example 1 will not be described in detail. The difference from Example 1 is that a lug 87 structure is provided at the top of the outer edge of the first crucible 108, which is lapped on the carbon crucible wall 2 and forms a coaxial arrangement with the second crucible 3. The first crucible 108 and the second crucible 3 share the second heater 52; the trough 81 has 3 flow guiding channels 84 in the z direction.

[0058] In addition to the beneficial effects of Example 1, this embodiment has the beneficial effects of being more stable and not being affected by possible deformation of the second crucible 3 because the first crucible 108 is lapped on the carbon crucible wall 2.

[0059] Example 3 As Figure 5 、 Figure 6 shown, the difference between this embodiment and Example 1 is as follows: a) The first crucible 108 of this embodiment is provided with a flange 88, replacing the lug 87 in Example 2. The flange 88 is connected to the fixed structure in the furnace body, and the orientation of the first crucible 108 is fixed and does not rotate during the growth of silicon single crystals: b) The first crucible 108 of this embodiment is provided with 2 troughs 81 in the shape of a sector ring with openings in the z direction, and there are two feed pipes 6. The filter hole plate 83 is vertically arranged at the end of the sector ring-shaped trough 81; c) The first crucible 108 of this embodiment is provided with 2 flow guiding channels 84. The 2 flow guiding channels 84 are spirally descending in the circumferential direction near the inner wall of the first crucible 108, and the descending angle γ is 10°. The inner diameter of the second crucible 3 is 800 mm.

[0060] d) The flange 88 of the first crucible 108 of this embodiment is connected to the fixed structure in the furnace body, and the orientation of the first crucible is fixed and does not rotate during the growth of silicon single crystals; there is no intermediate partition between the trough 81 section of the first crucible 108 and the first heater 51, and the first crucible 108 directly receives the thermal radiation of the first heater 51.

[0061] e) The opening of the trough 81 of the first crucible 108 of this embodiment is provided with a trough cover plate 86 distributed in a ring shape. The trough cover plate 86 is a porous structure filter screen made of quartz ceramic material.

[0062] In addition to the beneficial effects of Embodiment 1, this embodiment also has the following beneficial effects: a) The first crucible 108 is placed more stably and reliably; b) The first crucible 108 does not rotate. A trough cover plate 86 with a filter structure is placed thereon. The seal between the feed pipe 6 and the trough cover plate 86 is more reliable, preventing the silicon fine powder in the granular silicon 71 from falling near the crystallization interface and interfering with the growth of the silicon single crystal ingot 73; c) The first crucible 108 does not rotate. The outer inclined wall 841 of the flow-diverting channel cooperates with the rotation of the second crucible 3 in the crystal pulling process, exerting a downward pressing effect on the molten silicon 72 at the edge of the second crucible 3, which can inhibit the thermal convection intensity of the molten silicon 72 rising upward at the edge of the second crucible 3 and reduce the oxygen impurities entering the molten silicon 72; The spiral descending flow-diverting channel 84, in addition to inhibiting the thermal convection movement of the molten silicon 72 rising upward at the edge of the second crucible 3, also lengthens the path of the molten silicon 72 flowing from the first crucible 108 to the second crucible 3, enabling the unmolten silicon microparticles to have sufficient time to melt; The flow-diverting channel 84, in cooperation with the rotation of the second crucible 3 in the crystal pulling process, also has a stirring effect on the molten silicon 72, making the impurity distribution uniform.

[0063] d) There is no intermediate partition between the trough 81 section of the first crucible 108 and the first heater 51. The first crucible 108 directly receives the thermal radiation of the first heater 51, effectively improving the heating efficiency and facilitating the independent control of the heating power; e) The filter hole plate 83 vertically arranged at the end of the fan-shaped trough 81 increases the buffering distance and buffering time of the molten silicon flow, which is beneficial for the uncompletely molten silicon microparticles 74 to be completely melted and prevents them from interfering with the normal growth of the crystalline silicon.

[0064] Embodiment 4 As Figure 7 、 Figure 8 shown, the difference between this embodiment and Embodiment 2 is that: a) In this embodiment, the boss 89 at the bottom of the trough 81 of the first crucible 108 replaces the lug 87 in Embodiment 2. The boss 89 is placed on the carbon crucible sidewall 2, which is more stable; there is no partition between the annular trough 81 and the first heater 51. The first crucible 108 directly receives the thermal radiation of the first heater 51, effectively improving the heating efficiency and facilitating the independent control of the heating power; b) In this embodiment, the flow-diverting channel 84 below the free liquid surface 721 of the molten silicon is widened in the circumferential direction of the second crucible 3. The beneficial effect is that it provides a buffer interval for the uncompletely molten silicon microparticles 74, enabling them to be fully melted and preventing them from interfering with the normal growth of the crystalline silicon.

[0065] The above are only the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A first crucible for growing silicon single crystals by continuous feeding in the Czochralski method, characterized in that, The main body of the first crucible is annular in the x-y plane cross-section, and the annulus includes a quasi-circular ring, a quasi-elliptical ring or a quasi-polygonal ring. The first crucible is provided with one or more z-direction openings and a charging groove that is annular or annular-segment-shaped in the horizontal plane cross-section. At least one downward flow-diverting channel is provided below the charging groove, and a filter perforated plate is provided near the joint of the flow-diverting channel and the charging groove.

2. The first crucible according to claim 1, characterized in that, The outer wall of the inner ring edge of the charging groove is an air flow guiding surface that is inclined or curved in the xoz cross-section, and the inclination angle α of the inclined line or arc from bottom to top is 20° to 85°.

3. The first crucible according to claim 1, wherein At least one of the structures of lug, flange or boss is provided at the outer edge of the first crucible.

4. The first crucible according to claim 1, characterized in that, One or more charging groove covers are provided in an annular distribution at the opening of the charging groove.

5. The first crucible according to claim 4, wherein The charging groove cover is a porous structure filter screen made of ceramic or quartz material.

6. The first crucible according to claim 1, characterized in that, The total arc length of the outer diameter of the flow-diverting channel that blocks the molten silicon surface in the second crucible is less than 1 / 2 of the inner circumference of the second crucible at this position.

7. The first crucible according to claim 1, wherein, The flow-diverting channel is spirally descending in the circumferential direction of the second crucible, and the descending angle is γ, 5° < γ < 75°.

8. The first crucible according to claim 1, wherein The material of the first crucible contains silicon nitride (Si3N4) or silicon oxynitride (Si2N2O), and the proportion of nitrogen element in the material of the first crucible is 4% to 40% by weight ratio.

9. A melting material and crystal pulling device for continuously feeding materials to grow silicon single crystals by the Czochralski method, comprising: A feeding pipe, a second crucible, a carbon crucible side, a carbon crucible bottom, a second heater and a flow guiding and temperature control screen, characterized in that a first crucible according to any one of claims 1 to 8 is provided above the second crucible, the first crucible and the second crucible are coaxially arranged, and the distance between the outer bottom of the charging groove of the first crucible and the upper edge of the second crucible in the z direction is less than 150 mm.

10. The melt and crystal pulling device according to claim 9, characterized in that, The flow-diverting channel below the charging groove leads to below the free liquid surface of the molten silicon in the second crucible.

11. The melt and crystal pulling device according to claim 9, wherein, The lug, flange or boss of the first crucible is connected to the molten material and the crystal pulling device by at least one of the following methods: a) The first crucible is connected to the second crucible through the lug, flange or boss, and the first crucible and the second crucible rotate synchronously and in the same direction during the growth of the silicon single crystal. b) The first crucible is connected to the carbon crucible side through the lug, flange or boss, and the first crucible and the second crucible rotate synchronously and in the same direction during the growth of the silicon single crystal. c) The first crucible is connected to the fixed structure in the furnace body through the lug, flange or boss, and the orientation of the first crucible is fixed and does not rotate during the growth of the silicon single crystal.

12. The melt and crystal pulling device according to claim 9, wherein, There is no intermediate partition between the charging groove section of the first crucible and the second heater or the first heater, and the first crucible directly receives the thermal radiation of the second heater or the first heater.

13. The melt and crystal pulling device according to claim 10, characterized in that, The projection vector direction of the extension direction vector of the flow-diverting channel downward from the charging groove in the x-y plane is the same as the rotation direction of the second crucible.

14. The melt and crystal pulling device according to claim 9, characterized in that, There is at least one of the following characteristics: a) The second crucible and the first crucible are heated by the same group of heaters, and the heaters are designed with segmented heating power in the z direction. b) The first crucible is heated by a separately provided first heater. c) During the crystal pulling process, the relative positions of the second crucible and the first crucible are fixed, and the relative positions of the air flow guiding surface of the first crucible and the silicon single crystal growth interface are fixed. d) During the crystal pulling process, the relative position of the flow guiding and temperature controlling screen with respect to the position of the silicon single crystal growth interface is fixed.

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