CN102092718A - Method for preparing solar-grade polycrystalline silicon - Google Patents
Method for preparing solar-grade polycrystalline silicon Download PDFInfo
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- CN102092718A CN102092718A CN2009102019355A CN200910201935A CN102092718A CN 102092718 A CN102092718 A CN 102092718A CN 2009102019355 A CN2009102019355 A CN 2009102019355A CN 200910201935 A CN200910201935 A CN 200910201935A CN 102092718 A CN102092718 A CN 102092718A
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- silicon
- polycrystalline silicon
- solar energy
- grade polycrystalline
- preparation
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- 229910021420 polycrystalline silicon Inorganic materials 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title abstract description 20
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 39
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052796 boron Inorganic materials 0.000 claims abstract description 7
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 7
- 239000011574 phosphorus Substances 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 239000002210 silicon-based material Substances 0.000 claims description 30
- 229910052710 silicon Inorganic materials 0.000 claims description 29
- 239000010703 silicon Substances 0.000 claims description 29
- 230000008018 melting Effects 0.000 claims description 20
- 238000002844 melting Methods 0.000 claims description 20
- 238000002360 preparation method Methods 0.000 claims description 14
- 239000003153 chemical reaction reagent Substances 0.000 claims description 9
- 239000001257 hydrogen Substances 0.000 claims description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 7
- 239000007789 gas Substances 0.000 claims description 7
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 claims description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 150000002431 hydrogen Chemical class 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 4
- 238000005273 aeration Methods 0.000 claims description 3
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 3
- 239000000292 calcium oxide Substances 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 238000013467 fragmentation Methods 0.000 claims description 3
- 238000006062 fragmentation reaction Methods 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 229960001866 silicon dioxide Drugs 0.000 claims description 3
- SBEQWOXEGHQIMW-UHFFFAOYSA-N silicon Chemical compound [Si].[Si] SBEQWOXEGHQIMW-UHFFFAOYSA-N 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 238000007711 solidification Methods 0.000 abstract description 3
- 230000008023 solidification Effects 0.000 abstract description 3
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 238000003723 Smelting Methods 0.000 abstract 2
- 230000005611 electricity Effects 0.000 abstract 1
- 238000011031 large-scale manufacturing process Methods 0.000 abstract 1
- 239000002994 raw material Substances 0.000 abstract 1
- 229920005591 polysilicon Polymers 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000000126 substance Substances 0.000 description 7
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 2
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000005272 metallurgy Methods 0.000 description 2
- 230000005693 optoelectronics Effects 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 229910003822 SiHCl3 Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
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Abstract
The invention discloses a method for preparing solar-grade polycrystalline silicon. 3N-grade silicon metal is adopted as a raw material, and is purified through slagging and directional solidification in a vacuum smelting furnace, so that the silicon metal is purified into the solar-grade polycrystalline silicon with the purity of 99.9999 percent. Through the vacuum smelting furnace, the content of boron in the silicon metal is reduced to 0.5ppm from 5ppm, the content of phosphorus is reduce to 0.8ppm from 15pm, and the total impurities of the metal are reduced to less than 0.1ppm from 1,000ppm. The process flow is short, electricity consumption is low, the emission is avoided, the investment cost and production cost for polycrystalline silicon production can be greatly reduced, and the method is suitable for large-scale production.
Description
Technical field
The present invention relates to vacuum metallurgy material purification engineering field, especially relate to a kind of preparation method of solar energy grade polycrystalline silicon.
Background technology
Existing the most sophisticated polysilicon purifying technique is a Siemens Method.This method is to mix metallurgical grade silicon and hydrogen chloride gas in fluidized-bed reactor, and by described metallurgical grade silicon and hydrogenchloride generation chemical reaction, obtaining boiling point at last only has 31 ℃ trichlorosilicane, and described chemical equation is:
Si (solid)+3HCl (gas)=SiHCl3 (gas)+H2 (gas) (heat release).
To pass through in the vapor deposition reaction stove together with the silicon rod that is heated to 1100 ℃ again behind the mixture distillation of trichlorosilicane and hydrogen subsequently, thereby remove hydrogen, separate out solid-state silicon simultaneously, just become chunk polysilicon after smashing.So just can obtain purity and be 99.9999999% silicon.
The present cost of this method is generally more than 400 yuan/kilogram.Along with the formation of solar energy industry chain, the cost of photovoltaic generation has become the biggest factor that the restriction photovoltaic generation is promoted.Reduce the cost of photovoltaic generation, new mode must be arranged, therefore, exploring new solar energy level silicon production technique becomes focus.
The metallurgy method purifying polycrystalline silicon is not because chemical reaction takes place in silicon itself, only be to be undertaken by the mode of the high-temperature vacuum melting and the degassing at the impurity in the silicon, therefore, energy consumption is low, polluting for a short time, is the most promising a kind of method that reduces the solar energy polycrystalline silicon cost for purification.
Summary of the invention
Technical problem to be solved by this invention provides a kind of preparation method of solar energy grade polycrystalline silicon, technical process is short, simple to operate, the chemical reaction amount is little, current consumption is little, and non-pollution discharge, can reduce the cost of investment and the production cost of production of polysilicon significantly, can also carry out scale operation.
In order to achieve the above object, the preparation method of solar energy grade polycrystalline silicon provided by the invention comprises following steps:
Step 1, be that the Pure Silicon Metal fragmentation of 3N becomes granularity at 20～80 millimeters bulk silicon material, clean the pollution of removing described silicon material surface, put into vacuum melting furnace purity; The boron content of described Pure Silicon Metal less than 5ppm, phosphorus content less than 15ppm, metallic impurity total content less than 1000ppm; After the cleaning, described silicon material is dried;
Step 2, put into the reagent of 25ppm in described vacuum melting furnace, this reagent is made up of silicon-dioxide, calcium oxide and barium oxide, and the mass ratio of described three kinds of components is 3: 3: 4; Described reagent should be clipped in the described silicon material equably.
Step 3, to described vacuum melting stove evacuation, arrive after the vacuum reheat and heat up and make described silicon material fusing, follow-up continuous 1600 degree that are warmed up to of described silicon material fusing; Wherein said vacuum melting furnace begins heat temperature raising when its vacuum pressure is 100 handkerchiefs, during the fusing of described silicon material and the vacuum pressure in the follow-up temperature-rise period be less than 1 handkerchief.
Step 4, in described vacuum melting furnace, feed purity greater than 99.999% hydrogen, gas flow be per minute 2 to be raised to 20 liters, air pressure be normal pressure, aeration time is 2 hours;
Step 5, described vacuum melting furnace is progressively lowered the temperature, make described fused silicon material begin cooling from the bottom, and upwards carry out solidification and crystallization from the bottom, the crystallization velocity of described silicon material forms silicon ingot at last between 6～20 millimeters/hour;
Described silicon ingot is taken out in step 6, blow-on, and bottom, the top of excising described silicon ingot reach part all around, and the remainder of resulting described silicon ingot is the solar-grade polysilicon silicon ingot just; Excise described silicon ingot bottom, top and around during part, carry out resistivity measurement to described silicon ingot, resistivity is excised less than the part of 0.5 ohmcm.
By above-mentioned steps, can obtain purity at the solar-grade polysilicon of 5N to 6N; The content of boron in the Pure Silicon Metal can be reduced to 0.5ppm from 5ppm, the content of phosphorus is reduced to 0.8ppm from 15ppm, total metal content impurity is reduced to below the 0.1ppm from 1000ppm.By the selection of the chemical additive in above steps, can also obtain P type or N type polysilicon respectively, wherein can be controlled at respectively in the scope that helps most making the opto-electronic conversion behind the battery as the content that the phosphorus of electronics or hole carrier and boron are provided.
The preparation method's of solar energy grade polycrystalline silicon provided by the invention technical process is short, and simple to operate, the chemical reaction amount is little, and current consumption is little, and non-pollution discharge, can reduce the cost of investment and the production cost of production of polysilicon significantly; Compare existing chemical method, physics and chemistry method of the present invention makes production of polysilicon technology simpler, and facility investment is little, cost of investment have only existing chemical method 10% less than, production cost has only 1/3 of existing chemical method; Compare with the method for existing physics method purifying polycrystalline silicon, technology of the present invention is simple, and cost of investment is low, and production cost has only 60% of existing physics method, and yield rate improves greatly.Preparation method of the present invention can also carry out scale operation.
Description of drawings
The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments:
Fig. 1 is the preparation method's of a solar energy grade polycrystalline silicon of the present invention schema.
Embodiment
Be the preparation method's of solar energy grade polycrystalline silicon of the present invention schema as shown in Figure 1, a preferred embodiment of the present invention comprises the steps:
Step 1, be that the Pure Silicon Metal fragmentation of 3N becomes granularity at 20～80 millimeters bulk silicon material with purity, the boron content of described Pure Silicon Metal be 0.5ppm, phosphorus content less than 1ppm, metallic impurity total content less than 800ppm; Clean the pollution of removing described silicon material surface, after the cleaning, described silicon material is dried, bake out temperature is 200 degree; Described silicon material is put into vacuum melting furnace, method is described silicon material to be put into the quartz crucible of described vacuum melting furnace, lay successively from bottom to top, note during blowing the described silicon material size of different size is separated lay, reduce gap between the silicon material as far as possible, and when filling with substance is handled with care, and does not damage crucible;
Step 2, put into the reagent of 25ppm in described vacuum melting furnace, this reagent is made up of silicon-dioxide, calcium oxide and barium oxide, and the mass ratio of described three kinds of components is 3: 3: 4; Described reagent will be clipped in the described silicon material equably;
Step 3, the fire door of closing described vacuum melting furnace, the body of heater of following described vacuum melting furnace vacuumize, beginning heating during less than 100 handkerchiefs at described body of heater pressure heats up described body of heater gradually, after described body of heater pressure is less than 10 handkerchiefs, described body of heater is warmed up to makes described silicon material fusing, follow-up continuous 1600 degree that are warmed up to of described silicon material fusing;
Step 4, feed purity greater than 99.999% hydrogen in described vacuum melting furnace, gas flow is that 20 liters of per minutes, air pressure are normal pressure, and aeration time is 2 hours; Because hydrogen at high temperature is easy to generate blast, when feeding hydrogen, must take required measure, prevent that blast from taking place;
Step 5, progressively reduce the heating power of described vacuum melting furnace and make described fused silicon material begin from the bottom cooling, make described silicon material begin to solidify from the bottom of described crucible, form columnar grain, and upwards growth gradually, the whole solidification and crystallizations of described silicon material in whole crucible, the crystallization velocity of described silicon material is controlled between 6～20 millimeters/hour, forms silicon ingot at last;
Step 6, described silicon ingot is lowered the temperature, when the temperature of described silicon ingot was lower than 100 degrees centigrade, described silicon ingot was taken out in blow-on; Bottom, the top of excising described silicon ingot reach part all around, and the remainder of resulting described silicon ingot is the solar-grade polysilicon silicon ingot just; Excise described silicon ingot bottom, top and around during part, carry out resistivity measurement to described silicon ingot, the silicon ingot of resistivity less than 0.5 ohmcm partly excised.
By implementing the above-mentioned steps of the embodiment of the invention, can obtain the solar-grade polysilicon that purity is 5.8N, this solar-grade polysilicon can directly carry out the microsection manufacture solar cell, and the solar cell photoelectric efficiency of conversion of made can reach more than 14%.
By the selection of the chemical additive in above steps, can obtain P type or N type polysilicon respectively, wherein can be controlled at respectively in the scope that helps most making the opto-electronic conversion behind the battery as the content that the phosphorus of electronics or hole carrier and boron are provided.
More than by specific embodiment the present invention is had been described in detail, but these are not to be construed as limiting the invention.Under the situation that does not break away from the principle of the invention, those skilled in the art also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.
Claims (6)
1. the preparation method of a solar energy grade polycrystalline silicon is characterized in that, comprises following steps:
Step 1, be that the Pure Silicon Metal fragmentation of 3N becomes granularity at 20～80 millimeters bulk silicon material, clean the pollution of removing described silicon material surface, put into vacuum melting furnace purity;
Step 2, put into the reagent of 25ppm in described vacuum melting furnace, this reagent is made up of silicon-dioxide, calcium oxide and barium oxide, and the mass ratio of described three kinds of components is 3: 3: 4;
Step 3, to described vacuum melting stove evacuation, arrive after the vacuum reheat and heat up and make described silicon material fusing, follow-up continuous 1600 degree that are warmed up to of described silicon material fusing;
Step 4, in described vacuum melting furnace, feed hydrogen, gas flow be per minute 2 to be raised to 20 liters, air pressure be normal pressure, aeration time is 2 hours;
Step 5, described vacuum melting furnace is progressively lowered the temperature, make described fused silicon material begin cooling from the bottom, and upwards solidify, form silicon ingot at last from the bottom;
Described silicon ingot is taken out in step 6, blow-on, and bottom, the top of excising described silicon ingot reach part all around, and the remainder of resulting described silicon ingot is the solar energy grade polycrystalline silicon silicon ingot just.
2. the preparation method of solar energy grade polycrystalline silicon as claimed in claim 1 is characterized in that:
The boron content of Pure Silicon Metal described in the step 1 less than 5ppm, phosphorus content less than 15ppm, metallic impurity total content less than 1000ppm.
3. the preparation method of solar energy grade polycrystalline silicon as claimed in claim 1 is characterized in that:
Reagent described in the step 2 is clipped in the described silicon material equably.
4. the preparation method of solar energy grade polycrystalline silicon as claimed in claim 1 is characterized in that:
Vacuum melting furnace described in the step 3 begins heat temperature raising when its vacuum pressure is 100 handkerchiefs, during the fusing of described silicon material and the vacuum pressure in the follow-up temperature-rise period be less than 1 handkerchief.
5. the preparation method of solar energy grade polycrystalline silicon as claimed in claim 1 is characterized in that:
The purity of the hydrogen that feeds in the step 4 is greater than 99.999%.
6. the preparation method of solar energy grade polycrystalline silicon as claimed in claim 1 is characterized in that:
The speed of directional freeze is per hour 6～20 millimeters in the step 5.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009102019355A CN102092718A (en) | 2009-12-15 | 2009-12-15 | Method for preparing solar-grade polycrystalline silicon |
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| CN2009102019355A CN102092718A (en) | 2009-12-15 | 2009-12-15 | Method for preparing solar-grade polycrystalline silicon |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102856145A (en) * | 2011-06-30 | 2013-01-02 | 东京毅力科创株式会社 | Method for manufacturing silicon part and silicon part for etching treatment device |
| WO2013149560A1 (en) * | 2012-04-01 | 2013-10-10 | 江西赛维Ldk太阳能高科技有限公司 | Polycrystalline silicon ingot, preparation method thereof, and polycrystalline silicon wafer |
-
2009
- 2009-12-15 CN CN2009102019355A patent/CN102092718A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102856145A (en) * | 2011-06-30 | 2013-01-02 | 东京毅力科创株式会社 | Method for manufacturing silicon part and silicon part for etching treatment device |
| WO2013149560A1 (en) * | 2012-04-01 | 2013-10-10 | 江西赛维Ldk太阳能高科技有限公司 | Polycrystalline silicon ingot, preparation method thereof, and polycrystalline silicon wafer |
| US10227711B2 (en) | 2012-04-01 | 2019-03-12 | Jiang Xi Sai Wei Ldk Solar Hi-Tech Co., Ltd. | Method for preparing polycrystalline silicon ingot |
| US10253430B2 (en) | 2012-04-01 | 2019-04-09 | Jiang Xi Sai Wei Ldk Solar Hi-Tech Co., Ltd. | Method for preparing polycrystalline silicon ingot |
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Application publication date: 20110615 |