CN217499488U - Thermal field structure and single crystal furnace - Google Patents

Abstract

The application provides a thermal field structure and single crystal growing furnace, this thermal field structure includes: the heat preservation cylinder is internally provided with an accommodating cavity; the crucible assembly is accommodated in the accommodating cavity and comprises an outer layer crucible side and an inner layer crucible, the inner layer crucible is positioned on the inner side of the outer layer crucible side, and at least part of the inner wall of the outer layer crucible side is sunken along the circumferential direction of the outer layer crucible side to form a mounting groove; the heat preservation piece is embedded in the mounting groove; the heating device is accommodated in the accommodating cavity and is positioned around the outer side of the outer crucible port; the heat insulation piece is accommodated in the accommodating cavity and positioned between the heating device and the outer layer crucible side, and the longitudinal temperature gradient of the silicon melt is reduced, so that the oxygen content of the monocrystalline silicon is reduced, and the wire breakage rate is reduced.

Description

Thermal field structure and single crystal furnace

[ technical field ] A method for producing a semiconductor device

The utility model relates to a solar photovoltaic cell technical field especially relates to a thermal field structure and single crystal growing furnace.

[ background of the invention ]

With the continuous development of world economy, the demand of modern construction for efficient clean energy is continuously increased. Photovoltaic power generation is increasingly valued by countries in the world and is vigorously developed as a green energy source and one of the main energy sources for sustainable development of human beings. Monocrystalline silicon has a wide market demand as one of the basic materials for photovoltaic power generation.

At present, single crystal silicon is generally grown by the Czochralski method in a single crystal furnace, which is an apparatus for growing a dislocation-free single crystal by the Czochralski method by melting a silicon raw material by a heating device in an inert gas atmosphere. However, the quality of the monocrystalline silicon grown by the Czochralski method in the existing single crystal furnace is relatively general, which is not beneficial to improving the efficiency of the solar cell.

[ Utility model ] content

The application provides a thermal field structure and single crystal growing furnace is favorable to improving the efficiency of monocrystalline silicon quality in order to be used for promoting solar cell.

In a first aspect, an embodiment of the present application provides a thermal field structure, including: the heat preservation cylinder is internally provided with an accommodating cavity; the crucible assembly is accommodated in the accommodating cavity and comprises an outer layer crucible side and an inner layer crucible, the inner layer crucible is positioned on the inner side of the outer layer crucible side, and at least part of the inner wall of the outer layer crucible side is sunken along the circumferential direction of the outer layer crucible side to form a mounting groove; the heat preservation piece is embedded in the mounting groove; the heating device is accommodated in the accommodating cavity and is positioned around the outer side of the outer crucible side; and the heat insulation piece is accommodated in the accommodating cavity and is positioned between the heating device and the outer layer crucible port.

In the second aspect, the embodiment of this application provides a single crystal growing furnace, including furnace body, crucible, heating device, water-cooling heat shield, a heat preservation section of thick bamboo, draft tube and crystal pulling apparatus, single crystal growing furnace still includes that the crucible is bound, heat preservation and heat insulating part, and wherein, the crucible holding is in the crucible is bound, and the circumferencial direction that the at least part of inner wall that the crucible was bound along the crucible is sunken to be formed with the mounting groove, and heat insulating part inlays to be located in the mounting groove, and the heat insulating part sets up between heating device and crucible are bound.

Compared with the prior art, the technical scheme at least has the following technical effects:

the utility model provides a in thermal field structure and single crystal growing furnace, because the heat insulating part sets up between heating device and outer crucible nation, at the in-process that monocrystalline silicon grows, can reduce the thermal radiation influence of heating device to crucible subassembly bottom to reduce the longitudinal temperature gradient of silicon melt, reach the effect that reduces oxygen content in the monocrystalline silicon, thereby improved the quality of monocrystalline silicon, and then promoted solar cell's efficiency. In addition, because the heat preservation piece inlays and locates in the inboard mounting groove of outer crucible nation, can play certain heat preservation effect, avoid leading to the problem of brilliant difficulty because of the bottom temperature supercooling of silicon melt, reduced the broken string rate.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

[ description of the drawings ]

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 described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic structural diagram of a thermal field structure according to an embodiment of the present application.

Fig. 2 is an enlarged view of a portion of the thermal field structure shown in fig. 1 at a.

Fig. 3 is a schematic view of the heat insulating member and the heating device in the thermal field structure of fig. 1.

FIG. 4 is a schematic view of an outer crucible end of the crucible assembly in the thermal field configuration shown in FIG. 1.

FIG. 5 is an enlarged partial structure schematic view of the outer layer crucible pot shown in FIG. 4 at B.

FIG. 6 is another schematic view of the outer crucible end of the crucible assembly in the thermal field configuration shown in FIG. 1.

FIG. 7 is an enlarged partial structure schematic view of the outer layer crucible pot shown in FIG. 6 at C.

FIG. 8 is a schematic view of another configuration of the outer layer crucible port of the crucible assembly in the thermal field configuration shown in FIG. 1.

FIG. 9 is an enlarged partial schematic view of the outer layer crucible shell shown in FIG. 8 at D.

FIG. 10 is a schematic view of another arrangement of the outer crucible end of the crucible assembly in the thermal field configuration shown in FIG. 1.

FIG. 11 is an enlarged partial view of the outer layer crucible end shown in FIG. 10 at E.

Fig. 12 is a schematic structural diagram of a single crystal furnace according to an embodiment of the present application.

Reference numerals:

100-thermal field structure;

1-a heat preservation cylinder;

11-a housing chamber;

2-a crucible assembly;

21-outer layer crucible bond; 211 a-side wall; 211 b-bottom wall; 211 c-arc wall; 212-a mounting groove; 22-inner crucible;

3-heat preservation;

31-a first heat-preserving portion; 32-a second heat preservation part;

4-a heating device;

41-heating part; 42-mounting feet;

5-a thermal insulation;

51-insulation; 52-gap;

200-a single crystal furnace;

210-a furnace body;

220-crucible;

230-a guide shell;

240-water cooling heat shield;

250-a connector;

251-a lifting limiting part; 252-a support bar; 253-lifting the buckle;

260-lifting rod;

270-a crystal pulling apparatus;

280-monocrystalline silicon;

290-a silicon melt;

291-growth interface.

[ detailed description ] A

For better understanding of the technical solutions of the present application, the following detailed descriptions of the embodiments of the present application are provided with reference to the accompanying drawings.

It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

At present, single crystal silicon is generally grown by the Czochralski method in a single crystal furnace, which is an apparatus for growing a dislocation-free single crystal by the Czochralski method by melting a silicon raw material by a heating device in an inert gas atmosphere. Oxygen, which is the highest impurity content in single crystal silicon, is liable to induce the generation of secondary defects such as lattice dislocations, stacking faults, and concentric circles of a cell, thereby affecting the efficiency of a solar cell.

At present, the crucible for loading silicon raw materials is mainly a quartz crucible, and the quartz crucible can react with silicon melt: si + SiO ₂ The majority of the SiO formed will volatilize out of the growth interface as a gas, and a small portion will dissolve in the silicon melt and exist in the form of oxygen atoms in the silicon melt.

The level of oxygen in the single crystal silicon is determined by the level of oxygen in the silicon melt near the growth interface, which is away from the crucible wall. The source of oxygen in the silicon melt near the growth interface includes two pathways, one is by diffusion, oxygen from the high concentration zone into the vicinity of the growth interface; the other is to pass the oxygen-rich silicon melt near the crucible wall into the vicinity of the growth interface by thermal convection.

The existing single crystal furnace is generally designed for a thermal field, and the oxygen content in the monocrystalline silicon is reduced by adopting the modes of reducing the rotating speed of a crucible, reducing the pressure in the furnace, thinning the thickness of a bottom insulating layer below the bottom of the crucible and the like, but the effects of the modes on reducing the oxygen content in the monocrystalline silicon are limited.

In order to solve the above technical problem, an embodiment of the present application provides a thermal field structure, which at least includes a heat-insulating cylinder, a crucible assembly, a heat-insulating member, a heating device, and a heat-insulating member. Wherein, an accommodating cavity is arranged in the heat-insulating cylinder; the crucible assembly is accommodated in the accommodating cavity and comprises an outer layer crucible side and an inner layer crucible, the inner layer crucible is positioned on the inner side of the outer layer crucible side, and at least part of the inner wall of the outer layer crucible side is sunken along the circumferential direction of the outer layer crucible side to form an installation groove; the heat preservation piece is embedded in the mounting groove; the heating device is accommodated in the accommodating cavity and positioned around the outer side of the outer crucible pot; the heat insulation piece is accommodated in the accommodating cavity and is positioned between the heating device and the outer layer crucible port.

Referring to fig. 1 and 2, an embodiment of the present application provides a thermal field structure 100 for a single crystal furnace, which at least includes a heat-preserving cylinder 1, a crucible assembly 2, a heat-preserving member 3, a heating device 4, and a heat-insulating member 5. Wherein:

the heat preservation cylinder 1 is used for improving the heat preservation performance of the single crystal furnace, so that the overall energy consumption and the production cost of the single crystal furnace are greatly reduced. An accommodating cavity 11 is arranged in the heat-insulating cylinder 1, and the crucible assembly 2, the heat-insulating piece 3, the heating device 4 and the heat-insulating piece 5 are all accommodated in the accommodating cavity 11.

Specifically, the heat insulating cylinder 1 includes a side heat insulating layer (not shown), a top heat insulating layer (not shown), and a bottom heat insulating layer (not shown) disposed around the housing chamber 11. Any one or more of the top insulating layer, the bottom insulating layer, or the side insulating layer may be made of any other material having heat insulating and preserving effects, such as slag wool, asbestos, carbon fiber, graphite, and the like, without limitation. In the embodiment of the application, the top insulating layer, the bottom insulating layer and the side insulating layer can be made of carbon fiber materials.

The crucible assembly 2 includes an outer crucible end 21 and an inner crucible end 22, and the inner crucible end 22 is located the inner side of the outer crucible end 21, i.e., the outer crucible end 21 covers the inner crucible end 22. The inner crucible 22 is used for accommodating silicon raw materials and dopants, the outer crucible pot 21 can be used for supporting the inner crucible 22, and the outer crucible pot 21 can also play a heat preservation role so as to reduce the heat loss of the inner crucible 22.

Specifically, the outer crucible shell 21 and/or the inner crucible shell 22 are made of one or more of graphite, quartz or carbon-carbon composite materials. In the embodiment of the application, the material of the inner crucible 22 can be quartz, and the material of the outer crucible cover 21 can be graphite.

At least part of the inner wall of the outer layer crucible pot 21 is sunken to form an installation groove 212 along the circumferential direction of the outer layer crucible pot 21, and the heat preservation part 3 is embedded in the installation groove 212. The heat preservation member 3 is used for improving the heat preservation performance of the outer crucible cover 21 and preventing the silicon melt at the bottom of the inner crucible 22 from being overcooled, so that the wire breakage rate of the single crystal silicon is reduced, and the overall energy consumption and the production cost of the single crystal furnace are further reduced.

Specifically, the material of the heat insulating member 3 includes one or more of zirconia, alumina, aluminum nitride, graphite, quartz, or carbon-carbon composite material. In the embodiment of the present application, the material of the thermal insulation member 3 may be a carbon-carbon composite material.

In this application, because heat preservation 3 inlays in locating outer crucible nation 21 inboard mounting groove 212, can play certain heat preservation effect, avoid leading to the problem of brilliant difficulty because of the bottom temperature subcooling of silicon melt, reduced the broken string rate.

The heating device 4 is positioned around the outside of the outer layer crucible end 21 and the thermal shield 5 is received within the receiving cavity 11 and positioned between the heating device 4 and the outer layer crucible end 21. The heating device 4 is used for heating and melting the silicon raw material and the dopant contained in the inner crucible 22 under the action of the protective gas to obtain a silicon melt.

Specifically, the heating device 4 includes a heating portion 41 and at least two mounting feet 42, the heating portion 41 is disposed around the outer side of the outer layer crucible cover 21 via the mounting feet 42, and the thermal insulator 5 is disposed between the side heater and the side wall 211 a.

In this application, can weaken heating device 4 to the heat radiation of crucible subassembly 2 bottom through setting up heat insulating part 5 to reduce the longitudinal temperature gradient of silicon melt, and then reduce silicon melt heat convection, finally reduce near crucible wall oxygen-rich silicon melt and enter into the speed of defeated growth interface, with the purpose that reaches oxygen content in the reduction monocrystalline silicon, improved the quality of monocrystalline silicon, promoted solar cell's efficiency.

It is to be understood that the heating apparatus 4 can also include a bottom heater disposed below the bottom of the outer crucible end 21.

Referring to fig. 3, at least two gaps 52 are formed in the thermal insulation member 5 along the circumferential direction of the outer layer crucible shell 21, and any one of the mounting feet 42 is located in one of the gaps 52, so that the thermal insulation member 5 and the mounting foot 42 are prevented from interfering.

Specifically, the heat insulator 5 may include at least two heat insulating portions 51 separately disposed and annularly distributed, and any one of the heat insulating portions 51 has an arc shape. A gap 52 is formed between any adjacent two of the heat insulating portions 51, and the mounting leg 42 is disposed in the gap 52. The material of the thermal insulation member 5 includes one or more of zirconia, alumina, aluminum nitride, graphite, quartz or carbon-carbon composite material. In the embodiment of the present application, the material of the thermal insulation member 5 may be a carbon-carbon composite material.

The number of the mounting feet 42 may be two or N, where N is a positive integer greater than three, and the number of the thermal insulation parts 51 is the same as the number of the mounting feet 42, which is not limited herein. In the embodiment of the present application, the number of the mounting feet 42 and the thermal insulation part 51 may be two, and the two mounting feet 42 are symmetrically arranged along the axis of the crucible assembly 2.

With continued reference to FIG. 2, the height h of the insulation 5 ₂ 180 mm-560 mm, height h of the heat insulation piece 5 ₂ Specifically, the thickness can be 180mm, 200mm, 220mm, 240mm, 2mm60mm, 280mm, 300mm, 320mm, 340mm, 360mm, 380mm, 400mm, 420mm, 440mm, 460mm, 480mm, 500mm, 520mm, 540mm, 560mm, etc., without limitation thereto. Preferably, the height h of the thermal insulation element 5 ₂ May be 300 mm.

Thickness d of the thermal insulation 5 ₂ 10 mm-40 mm, thickness d of the heat insulation member 5 ₂ Specifically, the thickness may be 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, etc., but is not limited thereto. Preferably, the thickness d of the thermal insulation element 5 ₂ And may be 20 mm.

If the height h of the thermal insulation 5 is small ₂ And/or thickness d ₂ Too large, which may cause the temperature of the inner crucible 22 to be too low, resulting in the silicon feedstock and dopants not being completely melted to form a silicon melt; if the height h of the thermal insulation 5 is small ₂ And/or thickness d ₂ Too small, the thermal shield 5 is used to reduce the effect of the heating means 4 on the thermal radiation of the bottom of the crucible assembly 2 to a limited extent.

Referring to fig. 4 to 11, the outer layer crucible cover 21 includes a side wall 211a, a bottom wall 211b, and an arc-shaped wall 211c connected between the side wall 211a and the bottom wall 211b, and the mounting slot 212 is formed at the inner side of the side wall 211 a.

Specifically, the arc of the arc-shaped wall 211c may be 0 °, 5 °, 10 °, 15 °, 20 °, 25 °, etc., without limitation. In the present embodiment, the arc of the arc-shaped wall 211c may be 5 ° or 0 °.

Referring to fig. 4 to 7, in some embodiments, the mounting groove 212 is formed at the inner side of the sidewall 211a in a concave manner, and the bottom end of the mounting groove 212 may be located at or above the junction between the sidewall 211a and the arc-shaped wall 211 c.

Specifically, the distance L between the bottom end of the mounting groove 212 and the top end of the arc-shaped wall 211c along the height direction of the outer layer crucible edge 21 ₁ Less than 10 mm. A distance L between the bottom end of the mounting groove 212 and the top end of the arc-shaped wall 211c ₁ Specifically, the thickness may be 0mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or the like, but is not limited thereto. Preferably, a distance L between the bottom end of the mounting groove 212 and the top end of the arc-shaped wall 211c ₁ Can be 0mm, namely the bottom end of the mounting groove 212 andthe top ends of the arc-shaped walls 211c coincide as shown in fig. 7.

With continued reference to FIG. 5, the depth L of the mounting groove 212 ₂ 5-10 mm. Depth L of the mounting groove 212 ₂ Specifically, it may be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or the like. Preferably, the depth L of the mounting groove 212 ₂ May be 10 mm.

If the depth L of the mounting groove 212 ₂ The crucible is too large, so that the structural strength of the outer crucible end 21 is reduced, and the outer crucible end 21 cannot support the inner crucible 22; if the depth L of the mounting groove 212 ₂ Too small, so that the thickness d of the insulating member 3 ₁ And the heat preservation part 3 has limited heat preservation effect, so that the wire breakage rate is high and the crystallization is difficult.

Thickness d of the insulating member 3 ₁ 5 mm-10 mm. Thickness d of the insulating member 3 ₁ Specifically, it may be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or the like. Preferably, the thickness d of the thermal insulation member 3 ₁ May be 10 mm.

If the thickness d of the insulating member 3 ₁ Too large, requiring the depth L of the mounting groove 212 ₂ The structure strength of the outer crucible end 21 is reduced, so that the outer crucible end 21 cannot support the inner crucible 22; if the thickness d of the insulating member 3 is small ₁ Too small, the heat preservation function that heat preservation piece 3 can play is limited, leads to the broken string rate higher, and the crystalization is comparatively difficult.

In some embodiments, the thickness d of the insulating member 3 at any position ₁ A depth L corresponding to the position of the mounting groove 212 ₂ The same, so that the inner crucible 22 is accommodated in the outer crucible pot 21, the side wall 211a of the inner crucible 22 can be completely attached to the inner wall of the outer crucible pot 21, and heat transfer from the outer crucible pot 21 to the inner crucible pot 22 is facilitated.

Height h of the insulating part 3 ₁ Is 100 mm-150 mm. Height h of the insulating part 3 ₁ Specifically, the thickness may be 100mm, 105mm, 110mm, 115mm, 120mm, 125mm, 130mm, 135mm, 140mm, 145mm, 150mm, etc., and is not limited thereto. Preferably, the height h of the thermal insulation 3 ₁ May be 120 mm.

If the height h of the heat-insulating member 3 is small ₁ Too large may result in the silicon melt still having a large longitudinal temperature gradient and thus being unable to maintain a sufficient temperature gradientReducing the oxygen content in the monocrystalline silicon; if the height h of the heat-insulating member 3 is small ₁ Too small, the heat preservation function that heat preservation piece 3 can play is limited, leads to the broken string rate higher, and the crystallization is comparatively difficult.

Referring to fig. 8 and 9, in some embodiments, the outer crucible end 21 includes a side wall 211a, a bottom wall 211b, and an arc-shaped wall 211c connected between the side wall 211a and the bottom wall 211b, and the mounting slot 212 is formed continuously inside the side wall 211a and the arc-shaped wall 211 c.

Specifically, the mounting groove 212 includes a first portion (not shown) formed at an inner side of the sidewall 211a and a second portion (not shown) formed at an inner side of the arc-shaped wall 211c, which are continuously connected. The insulating member 3 includes a first insulating portion 31 and a second insulating portion 32, the first insulating portion 31 extending in the height direction of the crucible assembly 2 and being embedded in the first portion, and the second insulating portion 32 extending in the contour direction of the arc-shaped wall 211c and being embedded in the second portion.

The length of the second portion in the direction of the contour of the curved wall 211c is not more than one-half the length of the curved wall 211c in the direction of the contour thereof. Since the bottom of the outer crucible end 21 is mainly used to support the inner crucible 22 and the silicon raw material and dopant located in the inner crucible 22, the bottom wall 211b of the outer crucible end 21 needs to have a certain structural strength. If the length of the second portion in the direction of the contour of the arcuate wall 211c is too large, the structural strength of the bottom of the outer crucible end 21 is reduced, and damage may occur. Depth L of the mounting groove 212 ₂ Thickness d of the heat insulating member 3 ₁ And a height h ₁ May be the same as in the previous embodiments and will not be described herein.

Referring to FIGS. 10 and 11, in some embodiments, the depth L of the mounting slot 212 is measured along the height of the outer layer crucible port 21 ₂ Gradually decrease.

Specifically, the mounting groove 212 may be formed only on the inner side of the side wall 211a, or the mounting groove 212 may be continuously formed on the inner sides of the side wall 211a and the arc-shaped wall 211 c. Since the bottom of the outer crucible end 21 is mainly used for supporting the inner crucible 22 and the silicon raw material and dopant in the inner crucible 22, the bottom wall 211b of the outer crucible end 21 needs to have certain structural strength, and such a structureThe design makes the bottom of outer layer crucible nation 21 have certain structural strength. Depth L of the mounting groove 212 ₂ Thickness d of the heat insulating member 3 ₁ And a height h ₁ May be the same as in the previous embodiments and will not be described herein.

Referring to fig. 12, the embodiment of the present application provides a single crystal furnace 200, which at least includes a furnace body 210, a crucible 220, a heating device 4, a water-cooling heat shield 240, a heat-preserving cylinder 1, a guide cylinder 230, and a crystal pulling device 270, wherein the crucible 220, the heating device 4, the water-cooling heat shield 240, the heat-preserving cylinder 1, the guide cylinder 230, and the crystal pulling device 270 are all accommodated in the furnace body 210. Wherein:

heating device 4 is used to heat the silicon feedstock and dopant within crucible 220 such that the silicon feedstock and dopant are melted to form silicon melt 290.

Water-cooled heat shield 240 may reduce the temperature of the surface of single crystal silicon 280, increase the temperature gradient within single crystal silicon 280, and may substantially increase the growth rate of single crystal silicon 280 without changing the temperature gradient of silicon melt 290.

The structure and function of the thermal insulation cylinder 1 are the same as those of the thermal insulation cylinder 1 in the thermal field structure 100, and are not described again here.

Since the oxygen content in the silicon wafer has strict requirements to avoid serious accidents such as burning of the manufactured chip in the using process, the oxygen concentration in silicon melt 290 needs to be reduced, while the oxygen element in silicon melt 290 mostly exists in the form of SiO, and the guide cylinder 230 is arranged to collect the protective gas (argon and/or nitrogen) to the center of the crucible 220, so that the volatilization of SiO is accelerated, and the oxygen concentration in the melt can be greatly reduced. Meanwhile, the guide cylinder 230 can also play a role of heat shielding, and the gathered protective gas can accelerate the cooling of the monocrystalline silicon 280, increase the axial temperature gradient of the monocrystalline silicon 280, and improve the growth rate of the monocrystalline silicon 280.

Crystal puller 270 is used to hold the seed crystal and to drive the seed crystal downward in the pulling direction to dip into silicon melt 290 obtained by melting crucible 220 by heating. When silicon atoms in silicon melt 290 form crystals at growth interface 291 (solid-liquid interface) according to the silicon atom arrangement structure of the seed crystal, crystal pulling apparatus 270 may drive the seed crystal to rise in the pulling direction to form an ingot.

In some embodiments, the single crystal furnace 200 further includes a crucible pot (not shown in the drawings), a heat insulating member 3, and a heat insulating member 5, wherein the crucible 220 is accommodated in the crucible pot, at least a portion of the inner wall of the crucible pot is recessed along the circumferential direction of the crucible pot to form a mounting groove 212, the heat insulating member 3 is embedded in the mounting groove 212, and the heat insulating member 5 is disposed between the heating device 4 and the crucible pot. The structures and functions of the crucible cover, the thermal insulation member 3 and the thermal insulation member 5 are the same as those of the outer layer crucible cover 21, the thermal insulation member 3 and the thermal insulation member 5 in the thermal field structure 100, and are not described again.

In some embodiments, the single crystal furnace 200 further comprises a connector 250 and a lifting bar 260, wherein the lifting bar 260 is used to lift the water-cooled heat shield 240.

Specifically, one end of the lifting rod 260 is fixed on the side wall 211a of the furnace body 210 and connected to a motor (not shown in the figure), and the other end of the lifting rod 260 is connected to the water-cooled heat shield 240, so that the water-cooled heat shield 240 can be lifted or lowered by controlling the rotation of the motor.

In the seeding process, the distance between the bottom of the water-cooling heat shield 240 and the surface of the growth interface 291 of the silicon melt 290 is increased by the lifting rod 260, so that the heat absorption capacity of the water-cooling heat shield 240 to the surface of the silicon melt 290 is weakened, the temperature of the growth interface 291 is more stable, and the seeding success rate is improved; in the process of isodiametric growth, the distance between the bottom of the cold and hot screen and the growth interface 291 of the silicon melt 290 is reduced by the lifting rod 260, so that the growth of the monocrystalline silicon 280 is more stable, the heat absorption capacity of the water-cooling and hot screen 240 to the crystal bar is improved, the temperature of the crystal bar is lowered, the longitudinal temperature gradient of the crystal bar is increased, and the variable-temperature gradient crystal pulling is realized.

The connecting member 250 is used to connect the lifting rod 260 and the guide cylinder 230. The connecting member 250 includes a lifting-limiting portion 251, a supporting rod 252 and a lifting buckle 253. Two ends of the supporting rod 252 are respectively connected to the lifting limiting portion 251 and the guide cylinder 230, one end of the lifting buckle 253 is fixedly connected to the lifting rod 260, and the other end of the lifting buckle 253 is clamped on the supporting rod 252.

When the lifting rod 260 is lifted upwards, the distance between the guide cylinder 230 and the surface of the silicon melt 290 is unchanged, that is, the lifting of the water-cooling heat shield 240 does not drive the guide cylinder 230 to lift upwards; when the lifting buckle 253 is lifted to the lifting limiting portion 251 along the supporting rod 252, if the lifting rod 260 continues to lift upwards, the lifting buckle 253 drives the lifting limiting portion 251 to move upwards, and simultaneously drives the guide cylinder 230 to move upwards.

When the lifting rod 260 descends downwards, the lifting buckle 253 also descends to the flanging part of the guide cylinder 230 along the supporting rod 252 to drive the guide cylinder 230 to descend, when the guide cylinder 230 descends to the position where the flanging of the guide cylinder 230 is abutted to the heat preservation cylinder 1, the position of the guide cylinder 230 is not changed any more, and at the moment, when the lifting rod 260 descends continuously, the water-cooling heat shield 240 descends continuously, so that the water-cooling heat shield 240 moves downwards independently relative to the guide cylinder 230, the distance between the bottom of the water-cooling heat shield 240 and the surface of the silicon melt 290 is further reduced, the heat absorption capacity of the water-cooling heat shield 240 on a crystal rod is improved, and variable-temperature gradient crystal pulling is realized.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (11)

1. A thermal field structure, comprising:

the heat preservation cylinder is internally provided with an accommodating cavity;

the crucible assembly is contained in the containing cavity and comprises an outer layer crucible side and an inner layer crucible, the inner layer crucible is positioned on the inner side of the outer layer crucible side, and at least part of the inner wall of the outer layer crucible side is sunken along the circumferential direction of the outer layer crucible side to form a mounting groove;

the heat preservation piece is embedded in the mounting groove;

the heating device is accommodated in the accommodating cavity and is positioned around the outer side of the outer layer crucible side;

and the heat insulation piece is accommodated in the accommodating cavity and is positioned between the heating device and the outer layer crucible side.

2. The thermal field structure of claim 1, wherein the outer layer crucible shell comprises a side wall, a bottom wall, and an arc-shaped wall connected between the side wall and the bottom wall, and the mounting slot is formed inside the side wall.

3. The thermal field structure of claim 2, wherein a distance L between a bottom end of the mounting groove and a top end of the arc-shaped wall in a height direction of the outer layer crucible pot ₁ Less than 10 mm.

4. The thermal field structure of claim 1, wherein the outer layer crucible pot comprises a side wall, a bottom wall, and an arc-shaped wall connected between the side wall and the bottom wall, and the mounting slot is continuously formed on the inner sides of the side wall and the arc-shaped wall.

5. A thermal field structure according to any one of claims 2 to 4, characterized in that the depth L of the installation groove ₂ 5-10 mm.

6. The thermal field structure of claim 5, wherein the mounting slot has a depth L along the height of the outer crucible pot ₂ Gradually decrease.

7. The thermal field structure of claim 5, wherein the insulating member has a height h ₁ 100 mm-150 mm; and/or the thickness d of the thermal insulation member ₁ 5 mm-10 mm.

8. The thermal field structure of claim 2, wherein the heating device comprises a heating portion and at least two mounting feet, the heating portion being disposed around an outer side of the outer crucible shell via the mounting feet, the thermal shield being disposed between the heating portion and the side wall;

the heat insulating part is followed the circumferencial direction of outer crucible nation is formed with two at least clearances, arbitrary one the installation foot is located one in the clearance.

9. The thermal field structure of claim 8, wherein the thermal insulation has a height h ₂ 180 mm-560 mm; and/or the thickness d of the thermal insulation element ₂ Is 10 mm-40 mm.

10. The thermal field structure of claim 1, wherein the thermal insulation and/or the thermal insulation is one of zirconia, alumina, aluminum nitride, graphite, quartz, or a carbon-carbon composite.

11. The utility model provides a single crystal growing furnace, includes furnace body, crucible, heating device, water-cooling heat shield, heat preservation section of thick bamboo, draft tube and crystal and carries and draw the device, its characterized in that, single crystal growing furnace still includes crucible nation, heat preservation and heat insulating part, wherein, the crucible holding in the crucible nation, the at least part of the inner wall of crucible nation is followed the circumferencial direction of crucible nation is sunken to be formed with the mounting groove, heat preservation inlays to be located in the mounting groove, the heat insulating part set up in heating device with between the crucible nation.

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