CN103122482B - Prepare the method and apparatus of high-purity polycrystalline silicon - Google Patents
Prepare the method and apparatus of high-purity polycrystalline silicon Download PDFInfo
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- CN103122482B CN103122482B CN201310036359.XA CN201310036359A CN103122482B CN 103122482 B CN103122482 B CN 103122482B CN 201310036359 A CN201310036359 A CN 201310036359A CN 103122482 B CN103122482 B CN 103122482B
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- 229910021420 polycrystalline silicon Inorganic materials 0.000 title claims abstract description 77
- 238000000034 method Methods 0.000 title claims abstract description 35
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 152
- 239000010703 silicon Substances 0.000 claims abstract description 152
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 151
- 239000012535 impurity Substances 0.000 claims abstract description 134
- 239000002210 silicon-based material Substances 0.000 claims abstract description 95
- 239000007788 liquid Substances 0.000 claims abstract description 83
- 229920005591 polysilicon Polymers 0.000 claims abstract description 34
- 238000002425 crystallisation Methods 0.000 claims abstract description 19
- 230000008025 crystallization Effects 0.000 claims abstract description 19
- 238000007711 solidification Methods 0.000 claims abstract description 10
- 230000008023 solidification Effects 0.000 claims abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 33
- 239000000463 material Substances 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 19
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 19
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 16
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 16
- 238000002360 preparation method Methods 0.000 claims description 15
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 15
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 15
- 238000001816 cooling Methods 0.000 claims description 12
- 238000002844 melting Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 8
- 238000011068 loading method Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 abstract description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 42
- 229910002804 graphite Inorganic materials 0.000 description 36
- 239000010439 graphite Substances 0.000 description 36
- 238000005266 casting Methods 0.000 description 33
- 238000000137 annealing Methods 0.000 description 24
- 230000000694 effects Effects 0.000 description 19
- 238000009413 insulation Methods 0.000 description 10
- 239000010453 quartz Substances 0.000 description 10
- 238000005204 segregation Methods 0.000 description 8
- 238000010521 absorption reaction Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000007791 liquid phase Substances 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000004575 stone Substances 0.000 description 6
- 238000003723 Smelting Methods 0.000 description 4
- 230000005484 gravity Effects 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 235000013312 flour Nutrition 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- -1 silicon nitrides Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Abstract
The invention discloses a kind of method preparing high-purity polycrystalline silicon, comprise the steps: to provide filter member, filter member arranges the silicon material of molten state, make the silicon liquid in the silicon material of described molten state and infusibility magazins' layout, obtain the silicon liquid after purifying; Silicon liquid, directional solidification crystallization after described purifying is formed silicon ingot, obtains highly purified polysilicon.The invention also discloses a kind of device preparing high-purity polycrystalline silicon.The mode that the present invention adopts filtering and impurity removing to combine with directional freeze removal of impurities, effectively removes the impurity in silicon material, produces highly purified polysilicon, be suitable for preparing silicon solar cell.
Description
Technical field
The present invention relates to technical field of polysilicon production, especially a kind of method and apparatus preparing high-purity polycrystalline silicon.
Background technology
Solar-grade polysilicon is one of requisite raw material preparing silicon solar cell, and its preparation and method of purification are always large focuses of technical field of solar research.In actual production, highly purified solar-grade polysilicon is generally purify from industrial silicon material and obtain, the technological method adopted is varied, wherein directional freeze impurity removing technology is the most common also one of effective means the most in solar-grade polysilicon preparation, the crucible that ingot furnace put into by industrial silicon material melts by it, make the orientation in long brilliant process of the impurity in silicon material be discharged to silicon ingot head by controlling temperature in crucible, thus reach the object of removal of impurities.
After ingot furnace directional freeze, the most of impurity in silicon material is discharged to the head of silicon ingot.But because impurity is more, infusibility impurity is not kept apart with silicon liquid, in long brilliant process, part infusibility impurity is wrapped in the middle of silicon ingot, and causing still remainingly in the silicon ingot obtained has part infusibility impurity.How to remove this part impurity and become one of difficulties of directional solidification method silicon material removal of impurities.
Summary of the invention
The defect of the infusibility impurity be wrapped in silicon ingot is difficult to remove for overcoming prior art, the invention provides a kind of method and apparatus preparing high-purity polycrystalline silicon, the mode that the present invention adopts filtering and impurity removing to combine with directional freeze removal of impurities, effectively removes the impurity in silicon material, produce highly purified polysilicon, be suitable for preparing silicon solar cell.
First aspect, the invention provides a kind of method preparing high-purity polycrystalline silicon, comprises the steps:
Filter member is provided, filter member arranges the silicon material of molten state, make the silicon liquid in the silicon material of described molten state and infusibility magazins' layout, obtain the silicon liquid after purifying;
Silicon liquid, directional solidification crystallization after described purifying is formed silicon ingot, obtains highly purified polysilicon.
In the present invention, containing more impurity in original silicon material, after heating and melting, silicon liquid, the meltable impurity of melting and the infusibility impurity of bulk that is not completely melted is included in the silicon material of molten state, when the silicon material of molten state is through filter member, silicon liquid and meltable impurity can flow out from the filter opening filter member, and infusibility impurity then more greatly cannot through filter opening and be isolated in filter member because volume, thus realize being separated of silicon liquid and infusibility impurity; When silicon liquid, directional solidification crystallization after purifying, impurity is wherein directed the head being enriched to silicon ingot because segregation coefficient is little, thus is separated with silicon liquid by the impurity in silicon material further, obtains highly purified polysilicon product.
Preferably, the method for the highly purified polysilicon of described preparation, forms silicon ingot described by the silicon liquid, directional solidification crystallization after described purifying, comprises further after obtaining highly purified polysilicon:
Reduce silicon ingot temperature to anneal, come out of the stove after cooling, the impurity on removing silicon ingot surface, obtains highly purified polysilicon.
More preferably, described annealing, annealing temperature is 1400 ~ 400 DEG C, and annealing time is 1 ~ 5 hour.
Wherein, come out of the stove after described cooling, being generally cooled to 25 ~ 400 DEG C can come out of the stove.
Though annealing operation is nonessential in polysilicon preparation, comes out of the stove again after insulation annealing, can prevent silicon ingot from ftractureing; Silicon ingot in addition after annealing, the dislocation desity of silicon chip reduces, and resistivity and minority carrier life time decline.
Preferably, described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening.
Wherein, the shape of the filter opening on described crucible or filter screen, can need according to technique and easy to make, is set as circle, ellipse, square or rectangular or other irregular shapes.
Preferably, the filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm.
More preferably, described filter opening is the manhole of diameter 10mm or the square through-hole of length of side 10mm.Size and the impurity-eliminating effect of filter opening are closely related, and the size of filter opening is less, and impurity-eliminating effect is better, but after the fusing of silicon material, the lower leakage speed of silicon liquid is slow, very easily causes filter opening by situation about blocking.Practical experience proves, diameter or the length of side are that the filter opening of 10mm can reach preferably impurity-eliminating effect.
Preferably, described high temperature material is silicon nitride, silicon carbide or silicon oxide.In silicon material, infusibility impurity is mainly silicon nitride, silicon carbide or silicon oxide, and the material of filter screen is impurity itself, can make full use of the adsorption between impurity, makes infusibility impurity in molten state silicon material by bulk impurity absorption, further increases impurity-eliminating effect.
Wherein, the described mode arranging the silicon material of molten state in filter member is not limit.
Preferably, the described silicon material arranging molten state in filter member comprises further: loading solid silicon material above filter member, then carries out heating to filter member and makes the melting of silicon material, the silicon material of obtained molten state; Or
Heat solid silicon material in another one crucible, the silicon material of obtained molten state, is poured into the silicon material of this molten state in filter member.
In above-mentioned two kinds of modes, add the silicon material of hot preparation molten state, Heating temperature can not be too high, otherwise the infusibility impurity in silicon material is also melted.Preferably, described in add the silicon material of hot preparation molten state, Heating temperature is 1441 ~ 1650 DEG C.At such a temperature, only have elemental silicon and the meltable impurity fusing of small part, infusibility impurity such as silicon carbide, silicon nitride, silicon oxide still exist in solid form, are conducive to like this improving filter effect.
More preferably, described in add the silicon material of hot preparation molten state, Heating temperature is 1545 ~ 1650 DEG C.So both accelerate melt speed, improve preparation efficiency, in turn ensure that the effect of filtering and impurity removing.
Preferably, before filter member arranges the silicon material of molten state, also in described filter member, add a small amount of bulk impurity.In silicon material, infusibility impurity is mainly silicon nitride, silicon carbide or silicon oxide, a small amount of bulk impurity is additionally added during filtration, the adsorption between impurity can be utilized, make the infusibility impurity in molten state silicon material by the bulk impurity absorption additionally added, improve impurity-eliminating effect further.
Preferably, described bulk impurity is one or more in silicon nitride, silicon carbide, silicon oxide.
Preferably, described directional freeze crystallization is at the silicon liquid after purifying is placed in 1445 ~ 1360 DEG C, makes the crystallization of silicon liquid form silicon ingot.The brilliant speed of this duration is moderate, is conducive to the effect improving directed removal of impurities.
Second aspect, present invention also offers a kind of device preparing high-purity polycrystalline silicon, comprises filter member, and described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening.
Preferably, the filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm.More preferably, described filter opening is the manhole of diameter 10mm or the square through-hole of length of side 10mm.
Compared to prior art, the impurity removal process of a kind of silicon material of the present invention has following beneficial effect:
(1) according to required impurity-eliminating effect, can make the filter member of different size and shape, carry out the removal of impurities of silicon material, solve prior art and be difficult to remove the problem being wrapped in infusibility impurity in silicon ingot, technique is simple, good impurity removing effect;
(2) knot screen structure is simple, and easy to assembly, cost of manufacture is low, is suitable for industrial applications.
Accompanying drawing explanation
In order to be illustrated more clearly in technical scheme of the present invention, be briefly described to the accompanying drawing used required in embodiment below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the process flow sheet that the embodiment of the present invention prepares the method for high-purity polycrystalline silicon;
Fig. 2 is the structural representation of the device preparing high-purity polycrystalline silicon described in the embodiment of the present invention seven;
Fig. 3 is the structural representation of the device preparing high-purity polycrystalline silicon described in the embodiment of the present invention eight;
Fig. 4 is the structural representation of the device preparing high-purity polycrystalline silicon described in the embodiment of the present invention nine.
Embodiment
Below in conjunction with the accompanying drawing in embodiment of the present invention, the technical scheme in embodiment of the present invention is clearly and completely described.
Prepare a method for high-purity polycrystalline silicon, comprise the steps:
Filter member is provided, filter member arranges the silicon material of molten state, make the silicon liquid in the silicon material of described molten state and infusibility magazins' layout, obtain the silicon liquid after purifying;
Silicon liquid, directional solidification crystallization after described purifying is formed silicon ingot, obtains highly purified polysilicon.
In the present invention, containing more impurity in original silicon material, after heating and melting, silicon liquid, the meltable impurity of melting and the infusibility impurity of bulk that is not completely melted is included in the silicon material of molten state, when the silicon material of molten state is through filter member, silicon liquid and meltable impurity can flow out from the filter opening filter member, and infusibility impurity then more greatly cannot through filter opening and be isolated in filter member because volume, thus realize being separated of silicon liquid and infusibility impurity; When silicon liquid, directional solidification crystallization after purifying, impurity is wherein directed the head being enriched to silicon ingot because segregation coefficient is little, thus is separated with silicon liquid by the impurity in silicon material further, obtains highly purified polysilicon product.
The method of the highly purified polysilicon of described preparation, comprises further after the described silicon liquid, directional solidification crystallization by after described purifying forms silicon ingot:
Reduce silicon ingot temperature to anneal, come out of the stove after cooling, the impurity on removing silicon ingot surface, obtains highly purified polysilicon.
Described annealing, annealing temperature is 1400 ~ 400 DEG C, and annealing time is 1 ~ 5 hour.
Wherein, come out of the stove after described cooling, being generally cooled to 25 ~ 400 DEG C can come out of the stove.
Though annealing operation is nonessential in polysilicon preparation, comes out of the stove again after insulation annealing, can prevent silicon ingot from ftractureing; Silicon ingot in addition after annealing, the dislocation desity of silicon chip reduces, and resistivity and minority carrier life time decline.
Described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening.
Wherein, the shape of the filter opening on described crucible or filter screen, can need according to technique and easy to make, is set as circle, ellipse, square or rectangular or other irregular shapes.
Filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm.
Described filter opening is the manhole of diameter 10mm or the square through-hole of length of side 10mm.Size and the impurity-eliminating effect of filter opening are closely related, and the size of filter opening is less, and impurity-eliminating effect is better, but after the fusing of silicon material, the lower leakage speed of silicon liquid is slow, very easily causes filter opening by situation about blocking.Practical experience proves, diameter or the length of side are that the filter opening of 10mm can reach preferably impurity-eliminating effect.
Described high temperature material is silicon nitride, silicon carbide or silicon oxide.In silicon material, infusibility impurity is mainly silicon nitride, silicon carbide or silicon oxide, and the material of filter screen is impurity itself, can make full use of the adsorption between impurity, makes infusibility impurity in molten state silicon material by bulk impurity absorption, further increases impurity-eliminating effect.
Wherein, the described mode arranging the silicon material of molten state in filter member is not limit.
The described silicon material arranging molten state in filter member comprises further: loading solid silicon material above filter member, then carries out heating to filter member and makes the melting of silicon material, the silicon material of obtained molten state; Or
Heat solid silicon material in another one crucible, the silicon material of obtained molten state, is poured into the silicon material of this molten state in filter member.
In above-mentioned two kinds of modes, add the silicon material of hot preparation molten state, Heating temperature can not be too high, otherwise the infusibility impurity in silicon material is also melted.The described silicon material adding hot preparation molten state, Heating temperature is 1441 ~ 1650 DEG C.At such a temperature, only have elemental silicon and the meltable impurity fusing of small part, infusibility impurity such as silicon carbide, silicon nitride, silicon oxide still exist in solid form, are conducive to like this improving filter effect.
The described silicon material adding hot preparation molten state, Heating temperature is 1545 ~ 1650 DEG C.So both accelerate melt speed, improve preparation efficiency, in turn ensure that the effect of filtering and impurity removing.
Before filter member arranges the silicon material of molten state, also in described filter member, add a small amount of bulk impurity.In silicon material, infusibility impurity is mainly silicon nitride, silicon carbide or silicon oxide, a small amount of bulk impurity is additionally added during filtration, the adsorption between impurity can be utilized, make the infusibility impurity in molten state silicon material by the bulk impurity absorption additionally added, improve impurity-eliminating effect further.
Described bulk impurity is one or more in silicon nitride, silicon carbide, silicon oxide.
Described directional freeze crystallization is at the silicon liquid after purifying is placed in 1445 ~ 1360 DEG C, makes the crystallization of silicon liquid form silicon ingot.The brilliant speed of this duration is moderate, is conducive to the effect improving directed removal of impurities.
In addition, present invention also offers a kind of device preparing high-purity polycrystalline silicon, comprise filter member, described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening.
Filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm.
Described filter opening is the manhole of diameter 10mm or the square through-hole of length of side 10mm.
Below in conjunction with most preferred embodiment of the present invention, technical scheme of the present invention is further described.
Embodiment one
Please refer to Fig. 1, a kind of method preparing high-purity polycrystalline silicon, comprises the steps:
(1) filter member is provided: select internal diameter size to be the quartz crucible of 700*700mm, evenly arranging 9 diameters in quartz crucible bottom surface is 10mm manhole, obtains filter member; Select the graphite cake of 750*750mm simultaneously, on its surface by the set-up mode of manhole in filter member, 9 diameter 20mm manholes are set, as graphite bolster plate.
(2) melt and filtration: filter member special for step (1) is placed on graphite bolster plate, and each manhole in filter member is all overlapped completely with the manhole on graphite bolster plate, again filter member and graphite bolster plate are placed on the ingot casting crucible of 700*700mm in the lump, first in filter member, add 20 blocks of silicon nitrides and silicon carbide mixing bulk impurity, pour 156 kilograms of T1 material (wherein silicon ingot of the head 50mm of silicon ingot of obtaining for traditional method of T1 material again into, this part silicon ingot foreign matter content is more, polysilicon is prepared by method described in the present embodiment, effective); Then filter member, graphite bolster plate are put into polycrystalline silicon ingot or purifying furnace in the lump together with ingot casting crucible, build bell post-heating, (melt, long crystalline substance and process of cooling all have pressure requirements to make in-furnace temperature maintain 1550 DEG C, these are all known to the skilled person, repeat no more) herein, silicon material is melted, obtains the silicon material of molten state, the silicon material of molten state includes silicon liquid, the meltable impurity of melting and the infusibility impurity of bulk; Silicon material gravitate in filter member of molten state flows downward, and be filtered part and filter, silicon liquid and meltable impurity flow out from the manhole filter member, and the infusibility impurity of bulk is then because volume cannot be isolated in filter member through manhole more greatly; The ingot casting crucible be filtered below part from the silicon liquid of manhole outflow collects.
(3) directional freeze is long brilliant: slowly promote heat insulating cage and cancel insulation, the temperature of silicon liquid in ingot casting crucible is maintained 1432 ~ 1410 DEG C, long brilliant 20 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(4) annealing cooling: reduce in-furnace temperature to 900 DEG C, insulation annealing 2 hours; Then be cooled to 300 DEG C, come out of the stove.
(5) removal of impurity: be cooled to after room temperature until silicon ingot and remove filter member, silicon ingot is taken out from ingot casting crucible, the grey black impurity on removing silicon heavy stone used as an anchor surface, obtain highly purified polycrystal silicon ingot, be limited to the aperture of filter member, filter effect cannot reach 100%, but main impurity is by filtering, and therefore the long brilliant rear silicon ingot surface of directional freeze there will be the impurity layer of small area.
(6) the block infusibility impurity weighed, weight is 6.3 kilograms, and the effective filterability calculating filter member is 96.0%, wherein the ratio of the silicon product that obtains after referring to and using filter member process of effective filterability described in the embodiment of the present invention and the weight of silicon raw material.
Embodiment two
Prepare a method for high-purity polycrystalline silicon, comprise the steps:
(1) filter member is provided: select internal diameter size to be the ceramic crucible of 900*900mm, being evenly drilled with 24 diameters in ceramic crucible bottom surface is 15mm manhole, obtains filter member.Select the graphite cake of 950*950mm simultaneously, on its surface by the set-up mode of manhole in filter member, 24 diameter 25mm manholes are set, as graphite bolster plate.
(2) melt: provide smelting pot, loads 300 kilograms of silica flour material, puts into High Temperature Furnaces Heating Apparatus, and with 1650 DEG C of fusings 5 hours, obtain the silicon material of molten state, the silicon material of molten state included the infusibility impurity of silicon liquid, meltable impurity and bulk.
(3) filter: filter member special for step (1) is placed on graphite bolster plate, and each flexible through hole in filter member is all overlapped completely with the manhole on graphite bolster plate, again filter member and graphite bolster plate are placed on the ingot casting crucible of 900*900mm in the lump, 1 kilogram of silicon oxide bulk impurity is added in filter member, bulk impurity is laid in the bottom of filter member, then silicon material step (2) being melted the molten state obtained slowly is sprinkled upon in described filter member, now the silicon material of molten state is subject to action of gravity toward current downflow, infusibility impurity wherein and the meltable impurity of part are attracted in the silicon oxide bulk impurity added in advance, silicon liquid is then through silicon oxide bulk impurity, flow out from the manhole of filter member, collected by ingot casting crucible, obtain the silicon liquid after purifying.
(4) directional freeze is long brilliant: the silicon liquid after purifying is put into polycrystalline silicon ingot or purifying furnace in the lump together with ingot casting crucible, opens heat insulating cage and heats up, the temperature of silicon liquid in ingot casting crucible is maintained 1445 ~ 1420 DEG C, long brilliant 25 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(5) annealing cooling: lower heat insulating cage and reduce heating power, reduces in-furnace temperature to 400 DEG C, insulation annealing 1 hour; Then be cooled to 25 DEG C, come out of the stove, from ingot casting crucible, take out silicon ingot, the grey black impurity on removing silicon heavy stone used as an anchor surface, obtains highly purified polycrystal silicon ingot.
Embodiment three (experimental example)
Prepare a method for high-purity polycrystalline silicon, comprise the steps:
(1) provide filter member: select 220 crucibles, be evenly drilled with 2 row 3 to arrange totally 6 diameters be 1mm manhole in 220 crucible bottom surfaces, obtains filter member; Select supporting graphite bolster plate, wherein graphite bolster plate being also provided with 2 row 3, to arrange totally 6 diameters be 5mm manhole simultaneously.
(2) melt and filtration: filter member special for step (1) is placed on graphite bolster plate, and each flexible through hole in filter member is all overlapped completely with the manhole on graphite bolster plate, then filter member and graphite bolster plate are placed on 220 crucibles of non-perforate bottom another in the lump, filter member loads 4.2 kilograms of overflow material, and (wherein overflow material refers in traditional silicon ingot castingprocesses, cause part silicon hydrorrhea to flow to overflow cotton because crucible breaks, graphite base plate is or/and on miscellaneous part, because on these parts, dirt is more, therefore this part silicon material impurity is more, polysilicon is prepared by method described in the embodiment of the present invention, effective), then by filter member, graphite bolster plate puts into ingot furnace in the lump together with ingot casting crucible, building bell post-heating makes in-furnace temperature maintain 1441 DEG C, silicon material is melted, obtain the silicon material of molten state, the silicon material of molten state includes silicon liquid, the meltable impurity of melting and block infusibility impurity, silicon material gravitate in filter member of molten state flows downward, and be filtered part and filter, silicon liquid and meltable impurity flow out from the manhole filter member, and the infusibility impurity of bulk is then because volume cannot be isolated in filter member through manhole more greatly, the ingot casting crucible be filtered below part from the silicon liquid of manhole outflow collects.
(3) directional freeze is long brilliant: slowly promote heat insulating cage and cancel insulation, the temperature of silicon liquid in ingot casting crucible is maintained 1432 ~ 1410 DEG C, long brilliant 20 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(4) annealing cooling: reduce in-furnace temperature to 1400 DEG C, insulation annealing 5 hours; Then be cooled to 400 DEG C, come out of the stove.
(5) removal of impurity: be cooled to after room temperature until silicon ingot and remove filter member, and take out silicon ingot from ingot casting crucible, the black impurity on removing silicon heavy stone used as an anchor surface, obtains highly purified polycrystal silicon ingot.Weigh the block infusibility impurity in filter member, weight is 0.34 kilogram, and the effective filterability calculating filter member is 92.0%.
Embodiment four
Prepare a method for high-purity polycrystalline silicon, comprise the steps:
(1) filter member is provided: the filter member of customization silicon carbide material, filter member is the filter screen of the square through-hole with numerous length of side 5mm.
(2) melt: provide smelting pot, loads 200 kilograms of silica flour material, puts into High Temperature Furnaces Heating Apparatus, and with 1600 DEG C of fusings 5 hours, obtain the silicon material of molten state, the silicon material of molten state included the infusibility impurity of silicon liquid, meltable impurity and bulk.
(3) filter: filter member special for step (1) is placed on the ingot casting crucible that internal diameter size is 700*700mm, then silicon material step (2) being melted the molten state obtained slowly is sprinkled upon in described filter member, now the silicon material of molten state is subject to action of gravity toward current downflow, infusibility impurity wherein and the meltable impurity of part are attracted in the silicon oxide bulk impurity added in advance, silicon liquid is then through silicon oxide bulk impurity, flow out from the square through-hole of filter member, collected by ingot casting crucible, obtain the silicon liquid after purifying.
(4) directional freeze is long brilliant: the silicon liquid after purifying is put into polycrystalline silicon ingot or purifying furnace in the lump together with ingot casting crucible, opens heat insulating cage and heats up, the temperature of silicon liquid in ingot casting crucible is maintained 1400 ~ 1380 DEG C, long brilliant 25 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(5) annealing cooling: reduce in-furnace temperature to 1000 DEG C, insulation annealing 4 hours; Then be cooled to 200 DEG C, come out of the stove, from ingot casting crucible, take out silicon ingot, the black impurity on removing silicon heavy stone used as an anchor surface, obtains highly purified polycrystal silicon ingot.
Embodiment five
(1) filter member is provided: the square sheet filtering net of customization silicon oxide material, wherein filter screen is 15mm square through-hole with the numerous length of side, get the described filter screen of two covers, stacked together, and make the relative lower screen of upper screen toward upper right angular variation 10mm, filter opening is staggered, obtains filter member.
(2) melt: provide smelting pot, loads 300 kilograms of T1 silicon material, puts into High Temperature Furnaces Heating Apparatus, and with 1450 DEG C of fusings 6 hours, obtain the silicon material of molten state, the silicon material of molten state included the infusibility impurity of silicon liquid, meltable impurity and bulk.
(3) filter: silicon material step (2) being melted the molten state obtained slowly is sprinkled upon in the special filter member of step (1), below filter member, collect silicon liquid with ingot casting crucible simultaneously, now the silicon material of molten state is subject to action of gravity toward current downflow, infusibility impurity is wherein isolated in upper filter member by the absorption of filter member and filteration, silicon liquid and meltable impurity are then through filter member, flow out from the square through-hole filter member, collected by ingot casting crucible, obtain the silicon liquid after purifying.
(4) directional freeze is long brilliant: the silicon liquid after purifying is put into polycrystalline silicon ingot or purifying furnace in the lump together with ingot casting crucible, opens heat insulating cage and heats up, the temperature of silicon liquid in ingot casting crucible is maintained 1380 ~ 1360 DEG C, long brilliant 25 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(4) annealing cooling: reduce in-furnace temperature to 700 DEG C, insulation annealing 3 hours; Then be cooled to 100 DEG C, come out of the stove, from ingot casting crucible, take out silicon ingot, the grey black impurity on removing silicon heavy stone used as an anchor surface, obtains highly purified polycrystal silicon ingot.
Embodiment six
Prepare a method for high-purity polycrystalline silicon, comprise the steps:
(1) filter member is provided: the filter member of customization silicon nitride material, filter member is the filter screen of the square through-hole with numerous length of side 1mm.
(2) melt: provide smelting pot, loads 300 kilograms of overflow material, puts into High Temperature Furnaces Heating Apparatus, and with 1550 DEG C of fusings 8 hours, obtain the silicon material of molten state, the silicon material of molten state included the infusibility impurity of silicon liquid, meltable impurity and bulk.
(3) filter: silicon material step (2) being melted the molten state obtained slowly is sprinkled upon in the special filter member of step (1), below filter member, collect silicon liquid with the ingot casting crucible of internal diameter size 900*900mm simultaneously, now the silicon material of molten state is subject to action of gravity toward current downflow, infusibility impurity is wherein isolated in upper filter member by the absorption of filter member and filteration, silicon liquid and meltable impurity are then through filter member, flow out from the square through-hole filter member, collected by ingot casting crucible, obtain the silicon liquid after purifying.
(3) directional freeze is long brilliant: the silicon liquid after purifying is put into polycrystalline silicon ingot or purifying furnace in the lump together with ingot casting crucible, opens heat insulating cage and heats up, the temperature of silicon liquid in ingot casting crucible is maintained 1432 ~ 1410 DEG C, long brilliant 30 hours; Now, the elementary silicon in silicon liquid gradually crystallization forms polysilicon, and the little impurity of segregation coefficient as the impurity such as metal or carbon in the easier enrichment in solid-liquid interface place in the liquid phase, finally long brilliant completely after be enriched to head, obtain silicon ingot.
(4) annealing cooling: reduce in-furnace temperature to 500 DEG C, insulation annealing 1.5 hours; Then be cooled to 50 DEG C, come out of the stove, from ingot casting crucible, take out silicon ingot, the black impurity on removing silicon heavy stone used as an anchor surface, obtains highly purified polycrystal silicon ingot.
Embodiment seven
Prepare a device for high-purity polycrystalline silicon, comprise filter member, described filter member is the crucible of bottom with filter opening, and specific implementation is:
Please refer to Fig. 2, a kind of device preparing high-purity polycrystalline silicon, comprise filter member 100, graphite bolster plate 200 and silicon liquid collection container (not marking in figure).
Wherein, described filter member 100 is the quartz crucible of bottom with filter opening, described quartz crucible be hollow and have the rectangular parallelepiped barrel-like structure of an opening; The quartz crucible side parallel with described quartz crucible open face is the bottom 101 of quartz crucible, the bottom of described quartz crucible is square, outer side is of a size of the wide 700mm of long 700mm, and the bottom of described quartz crucible is provided with the manhole 102 that 16 diameters are 10mm.
Wherein, described graphite bolster plate 200 is the graphite cake of the thick 20mm of the wide 750mm of long 750mm, the bottom of graphite cake is also provided with through hole, the quantity of described through hole and relative position all with filter member 100 bottom the quantity of manhole 102 and relative position identical, shape of through holes is not limit, such as can be circle, size is slightly larger than manhole, and such as through-hole diameter is 20mm; Described filter member 100 is placed on described graphite bolster plate 200 by bottom and the mode contacted of graphite bolster plate 200, and each manhole 102 of described filter member 100 is all completely overlapping with each through hole of described graphite bolster plate 200.
Wherein, silicon liquid collection container is commercially available common polycrystalline silicon ingot casting crucible, and bottom is square, and the length of side is 700mm, and described filter member 100 is arranged at directly over described polysilicon ingot crucible with graphite bolster plate 200.
Embodiment eight
Prepare a device for high-purity polycrystalline silicon, comprise filter member, described filter member is the crucible of bottom with filter opening.Specific implementation is:
Please refer to Fig. 3, a kind of device preparing high-purity polycrystalline silicon, comprise filter member 100, graphite bolster plate 200 and silicon liquid collection container 300.
Wherein, described filter member 100 is 220 crucibles of bottom with filter opening, and the bottom of described 200 is provided with the manhole 102 that 6 diameters are 15mm.
Wherein, described graphite bolster plate 200 is rectangle graphite cake, length is larger than the 220 crucible bottom surface length of sides, width is less than the 220 crucible bottom surface length of sides, and graphite bolster plate 200 is also provided with through hole, and the quantity of described through hole and relative position are all identical with relative position with the quantity of the manhole 102 bottom filter member 100, shape of through holes is not limit, such as can be square, size is slightly larger than manhole, and the such as through hole length of side is 25mm; Described filter member 100 is placed on described graphite bolster plate 200 by bottom and the mode contacted of graphite bolster plate 200, and each manhole 102 of described filter member 100 is all completely overlapping with each through hole of described graphite bolster plate 200.
Wherein, described silicon liquid collection container 300 is commercially available 220 common crucibles, and described graphite bolster plate 200 is arranged on above 220 crucibles by the mode that the surface of graphite bolster plate 200 is parallel with the bottom surface of 220 crucibles, and with the openings contact of 220 crucibles.
Embodiment nine
Prepare a device for high-purity polycrystalline silicon, comprise filter member and silicon liquid collection container, described filter member is the crucible of bottom with filter opening.Specific implementation is identical with embodiment seven, and it is the manhole of 1mm that institute's difference is that the bottom of described quartz crucible is provided with 24 diameters, as shown in Figure 4, in figure, and 100 filter member, 102 manholes, 200 graphite bolster plates.
Embodiment ten
Prepare a device for high-purity polycrystalline silicon, comprise filter member, described filter member is the filter screen that high temperature material is made, and described filter screen is provided with filter opening, and specific implementation is:
Prepare a device for high-purity polycrystalline silicon, comprise filter member and silicon liquid collection container.
Wherein, described filter member is the filter screen of the square through-hole with numerous length of side 5mm, and the global shape of filter screen is square, and the length of side is 950mm.
Wherein, described silicon liquid collection container is commercially available common polycrystalline silicon ingot casting crucible, and bottom is square, the length of side is 900mm, described filter screen is arranged at the overthe openings of described polysilicon ingot crucible, set-up mode for keeping flat, the openings contact of filter screen and polysilicon ingot crucible.
Embodiment 11
Prepare a device for high-purity polycrystalline silicon, comprise filter member, described filter member is the filter screen that high temperature material is made, and described filter screen is provided with filter opening, and specific implementation is:
Prepare a device for high-purity polycrystalline silicon, comprise filter member and silicon liquid collection container.
Wherein, described filter member comprises the filter screen of silicon nitride material, and with the square through-hole of numerous length of side 15mm on filter screen, the global shape of described filter screen is square, and the length of side is 750mm; Filter member is that two described filter screen stacked on top of one another form, and wherein the central shaft of upper screen is positioned at the central shaft upper right side of lower screen along 10.6mm place, miter angle direction.
Wherein, described silicon liquid collection container is commercially available common polycrystalline silicon ingot casting crucible, and bottom is square, the length of side is 700mm, described filter screen is arranged at the overthe openings of described polysilicon ingot crucible, set-up mode for keeping flat, the openings contact of filter screen and polysilicon ingot crucible.
Embodiment 12
Prepare a device for high-purity polycrystalline silicon, comprise filter member, described filter member is the filter screen that silicon nitride material is made, described filter screen is provided with filter opening, specific implementation is similar to embodiment ten, and institute's difference is, described filter opening is the square through-hole of length of side 1mm.
The above is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.
Claims (6)
1. prepare the method for high-purity polycrystalline silicon, it is characterized in that, comprise the steps:
Filter member is provided, also in described filter member, add a small amount of bulk impurity, described bulk impurity is one or more in silicon nitride, silicon carbide, silicon oxide, described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening, filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm, the silicon material of molten state is set afterwards in filter member, make the silicon liquid in the silicon material of described molten state and infusibility magazins' layout, obtain the silicon liquid after purifying;
Silicon liquid, directional solidification crystallization after described purifying is formed silicon ingot, obtains highly purified polysilicon.
2. prepare the method for high-purity polycrystalline silicon as claimed in claim 1, it is characterized in that, described, silicon liquid, directional solidification crystallization after described purifying is formed silicon ingot, comprise further after obtaining highly purified polysilicon:
Reduce silicon ingot temperature to anneal, come out of the stove after cooling, the impurity on removing silicon ingot surface, obtains highly purified polysilicon.
3. prepare the method for high-purity polycrystalline silicon as claimed in claim 1, it is characterized in that, the described silicon material arranging molten state in filter member comprises further:
Loading solid silicon material above filter member, then carries out heating to filter member and makes the melting of silicon material, the silicon material of obtained molten state; Or
Heat solid silicon material in another one crucible, the silicon material of obtained molten state, is poured into the silicon material of this molten state in filter member.
4. prepare the method for high-purity polycrystalline silicon as claimed in claim 3, it is characterized in that, described in add the silicon material of hot preparation molten state, Heating temperature is 1441 ~ 1650 DEG C.
5. prepare the method for high-purity polycrystalline silicon as claimed in claim 1, it is characterized in that, described high temperature material is silicon nitride, silicon carbide or silicon oxide.
6. prepare the device of high-purity polycrystalline silicon, it is characterized in that, comprise filter member, described filter member is the filter screen that bottom is made with crucible or the high temperature material of filter opening, also in described filter member, add a small amount of bulk impurity, described bulk impurity is one or more in silicon nitride, silicon carbide, silicon oxide, and the filter opening on described crucible and filter screen is the manhole of diameter 1 ~ 15mm or the arbitrary polygon through hole of the length of side 1 ~ 15mm.
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| CN104499049B (en) * | 2014-12-29 | 2017-05-24 | 江西赛维Ldk太阳能高科技有限公司 | Method for removing polysilicon hard inclusion in ingot casting process |
| CN107523861A (en) * | 2017-08-10 | 2017-12-29 | 镇江仁德新能源科技有限公司 | A kind of method that impurity is captured in directional solidification process |
| CN107574478A (en) * | 2017-09-15 | 2018-01-12 | 晶科能源有限公司 | A kind of processing method of silicon material small powder |
| CN109110766B (en) * | 2018-10-16 | 2023-09-01 | 青岛蓝光晶科新材料有限公司 | Method and device for efficiently purifying silicon material after medium smelting |
| CN115403047B (en) * | 2022-08-30 | 2023-12-08 | 浙大宁波理工学院 | Purification method and device for recycling silicon powder |
| CN115784236B (en) * | 2022-12-20 | 2024-07-30 | 宁夏海盛实业有限公司 | Industrial silicon impurity removing device and method |
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