WO2007148985A1 - Device and method for production of semiconductor grade silicon - Google Patents

Device and method for production of semiconductor grade silicon Download PDF

Info

Publication number
WO2007148985A1
WO2007148985A1 PCT/NO2007/000219 NO2007000219W WO2007148985A1 WO 2007148985 A1 WO2007148985 A1 WO 2007148985A1 NO 2007000219 W NO2007000219 W NO 2007000219W WO 2007148985 A1 WO2007148985 A1 WO 2007148985A1
Authority
WO
WIPO (PCT)
Prior art keywords
silicon
hot zone
ingots
crucible
semiconductor grade
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/NO2007/000219
Other languages
French (fr)
Inventor
Stein Julsrud
Tyke Laurence Naas
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rec Scanwafer AS
Original Assignee
Rec Scanwafer AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rec Scanwafer AS filed Critical Rec Scanwafer AS
Priority to US12/305,908 priority Critical patent/US20090314198A1/en
Priority to EP07793893A priority patent/EP2035604A1/en
Priority to JP2009516423A priority patent/JP2009541193A/en
Publication of WO2007148985A1 publication Critical patent/WO2007148985A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
    • C30B35/002—Crucibles or containers
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/20—Controlling or regulating
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
    • C30B11/002—Crucibles or containers for supporting the melt
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B28/00—Production of homogeneous polycrystalline material with defined structure
    • C30B28/04—Production of homogeneous polycrystalline material with defined structure from liquids
    • C30B28/06—Production of homogeneous polycrystalline material with defined structure from liquids by normal freezing or freezing under temperature gradient
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F10/00—Individual photovoltaic cells, e.g. solar cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/121—The active layers comprising only Group IV materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10T117/10—Apparatus
    • Y10T117/1024—Apparatus for crystallization from liquid or supercritical state
    • Y10T117/1032—Seed pulling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10T117/10—Apparatus
    • Y10T117/1024—Apparatus for crystallization from liquid or supercritical state
    • Y10T117/1092—Shape defined by a solid member other than seed or product [e.g., Bridgman-Stockbarger]

Definitions

  • This invention relates to a device and method for production of ingots of semiconductor grade silicon, including solar grade silicon.
  • solar light which irradiates the earth with vastly more energy than the present day consumption, including any foreseeable increase in human energy consumption.
  • solar cell electricity has up to date been too expensive to be competitive with nuclear power, thermal power etc. This needs to change if the huge potential of the solar cell electricity is to be realised.
  • the cost of electricity from a solar panel is a function of the energy conversion efficiency and the production costs of the solar panel.
  • one strategy for reducing the costs of solar cell electricity is increasing the energy conversion efficiency.
  • PV photovoltaic
  • DS directional solidification
  • oxides or oxide containing materials in contact with the molten metal introduce oxygen in the molten metal.
  • the oxygen leads to formation of SiO gas evaporating from the melt, and the SiO gas will subsequently react with graphite in the hot zone forming CO gas.
  • the CO gas enters the silicon melt and thus introduces carbon into the solid silicon. That is, the use of oxide or oxide- containing materials in the hot zone may cause a sequence of reactions leading to introduction of both carbon and oxygen in the solid silicon.
  • Typical values associated with the Bridgman method is interstitial oxygen levels of 2-6-10 17 /cm 2 and 2-6-10 17 /cm 2 of substitutional carbon.
  • the main objective of the invention is to provide a production method of high- purity ingots of semiconductor grade silicon which substantially reduces/eliminates the problem of carbon and oxygen contamination of the silicon metal.
  • a further objective of the invention is to provide a device for performing the inventive method.
  • the objective of the invention may be realised by the features as set forth in the description of the invention below, and/or in the appended patent claims.
  • the invention is based on the realisation that the problem with carbon and/or oxygen contamination of the silicon is coupled to presence of oxide or oxide- containing materials in the hot reducing environment of the furnaces, and that the presently used materials in the hot zone, such as electrical insulation, crucibles, load carrying building elements and thermal insulation may be replaced by materials void of oxides.
  • the method according to the first aspect of the invention may be employed for any known process including for crystallising semiconductor grade silicon ingots, including solar grade silicon ingots, such as the Bridgman process or related direct solidification methods, the block-casting process, and the CZ-process for growth of monocrystalline silicon crystals.
  • a device for manufacturing ingots of semiconductor grade silicon, monocrystalline or multicrystalline comprising a sealed hot zone with an inert atmosphere, where
  • the electric insulation in at least the hot zone is made of silicon nitride, Si 3 N 4 , and
  • the crucible is made of either silicon nitride (Si 3 N 4 ), silicon carbide (SiC), or a composite of these, optionally coated with a oxide free release coating
  • inert atmosphere means an atmosphere in contact with the materials of the device and silicon metal in the hot zone which is essentially chemically inert towards the materials of the device and the silicon metal phase, both in the solid and liquid state.
  • inert atmosphere includes any gas pressure of the inert atmosphere, including vacuum.
  • the device may be any known device for crystallising semiconductor grade silicon ingots, including solar grade silicon ingots, such as furnaces for carrying out the Bridgman process or related direct solidification processes, crystallisation pots for performing the block-casting process, CZ-pullers for performing CZ-growth of monocrystalline silicon crystals.
  • solar grade silicon ingots such as furnaces for carrying out the Bridgman process or related direct solidification processes, crystallisation pots for performing the block-casting process, CZ-pullers for performing CZ-growth of monocrystalline silicon crystals.
  • FIG. 1 is a schematic view of a prior art furnace for direct solidification of semiconductor grade ingots.
  • the chosen example is a typical furnace for performing directional solidification of multicrystalline silicon, as shown in Figure 1 which is a facsimile of Fig. 1 of the applicant's International patent application WO 2006/082085.
  • the furnace comprises a gas tight crystallisation chamber defined by insulation walls marked 2 on the figure.
  • An inner chamber is defined by floor 9 with frame 11, walls 10, and lid 5.
  • suction outlets 24 and injection lance 12 for maintaining an inert atmosphere in the inner chamber.
  • the metal 13 is contained in crucible 1, and the metal 13 is first melted and then subject to a directional solidification by regulating the operation of heating elements 8 and 21, and cooling circuit 4, 15, 16, 17, 19, 20, 22, and 23.
  • the objective of the invention when applied on this furnace may be obtained by employing a crucible 1 of silicon nitride, silicon carbide, or a composite of these, optionally coated with a oxide free release coating.
  • a suitable silicon nitride crucible is disclosed in NO 317 080, which teaches that a silicon nitride with a total open porosity between 40 and 60 volume% and where at least 50 % of the pores on the surface are larger than the mean diameter of the Si 3 N 4 -particles, does not wet liquid silicon such that the crucible will easily slip the solidified metal.
  • any crucible made of only silicon nitride and which does not wet liquid silicon may be employed.
  • a pure silicon nitride crucible contains no, or negligible amounts of oxygen/oxides.
  • the migration of oxygen from the crucible to the liquid metal is eliminated, such that interstitial oxygen levels in the solid metal and formation of SiO will be substantially reduced or eliminated.
  • the example of DS-furnace according to the invention employs walls 10, floor 9 with frame 11, lid 5, and lances 24 and 12 made of carbon.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Metallurgy (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Silicon Compounds (AREA)

Abstract

This invention relates to a device and method for production of ingots of semiconductor grade silicon, including solar grade silicon, where the presence of oxygen in the hot zone is substantially reduced or eliminated by employing materials void of oxides in the hot zone of the melting and crystallisation process. The method may be employed for any known process including for crystallising semiconductor grade silicon ingots, including solar grade silicon ingots, such as the Bridgman process, the block-casting process, and the CZ-process for growth of monoicrystalline silicon crystals. The invention also relates to devices for carrying out the melting and crystallisation processes, where the materials of the hot zone are void of oxides.

Description

Device and method for production of semiconductor grade silicon
This invention relates to a device and method for production of ingots of semiconductor grade silicon, including solar grade silicon.
Background The world supplies of fossil oil are expected to be gradually exhausted in the following decades. This means that our main energy source for the last century will have to be replaced within a few decades, both to cover the present energy consumption and the coming increase in the global energy demand.
In addition, many concerns are raised that the use of fossil energy increases the earth greenhouse effect to an extent that may turn dangerous. Thus the present consumption of fossil fuels should preferably be replaced by energy sources/carriers that are renewable and sustainable for our climate and environment.
One such energy source is solar light, which irradiates the earth with vastly more energy than the present day consumption, including any foreseeable increase in human energy consumption. However, solar cell electricity has up to date been too expensive to be competitive with nuclear power, thermal power etc. This needs to change if the huge potential of the solar cell electricity is to be realised.
The cost of electricity from a solar panel is a function of the energy conversion efficiency and the production costs of the solar panel. Thus one strategy for reducing the costs of solar cell electricity is increasing the energy conversion efficiency.
Prior art
In today's photovoltaic (PV) industry multicrystalline wafers for PV applications are cut from ingots that are cast in furnaces by directional solidification (DS) based on the Bridgman method. A main challenge in these processes is to maintain the purity of the silicon raw material. Two of the elements causing contamination problems are oxygen and carbon.
According to the "Handbook of Photo voltaic Science and Engineering", John Wiley & Sons, 2003, there is a problem in that oxides or oxide containing materials in contact with the molten metal (including migration through the release coating) introduce oxygen in the molten metal. The oxygen leads to formation of SiO gas evaporating from the melt, and the SiO gas will subsequently react with graphite in the hot zone forming CO gas. The CO gas enters the silicon melt and thus introduces carbon into the solid silicon. That is, the use of oxide or oxide- containing materials in the hot zone may cause a sequence of reactions leading to introduction of both carbon and oxygen in the solid silicon. Typical values associated with the Bridgman method is interstitial oxygen levels of 2-6-1017/cm2 and 2-6-1017/cm2 of substitutional carbon.
Build-up of carbon in the silicon metal may lead to formation of needle shaped SiC crystals, especially in the uppermost region of the ingot. These needle shaped SiC crystals are known to short-cut pn-junctions of the semiconductor cell, leading to drastically reduced cell efficiencies. Build up of interstitial oxygen may lead to oxygen precipitates and/or recombination active oxygen complexes after annealing of the formed silicon metal.
Objective of the invention The main objective of the invention is to provide a production method of high- purity ingots of semiconductor grade silicon which substantially reduces/eliminates the problem of carbon and oxygen contamination of the silicon metal.
A further objective of the invention is to provide a device for performing the inventive method. The objective of the invention may be realised by the features as set forth in the description of the invention below, and/or in the appended patent claims.
Description of the invention
The invention is based on the realisation that the problem with carbon and/or oxygen contamination of the silicon is coupled to presence of oxide or oxide- containing materials in the hot reducing environment of the furnaces, and that the presently used materials in the hot zone, such as electrical insulation, crucibles, load carrying building elements and thermal insulation may be replaced by materials void of oxides.
Thus in a first aspect of the invention there is provided a method for production of semiconductor grade silicon ingots, where the presence of oxygen in the hot zone is substantially reduced or eliminated by
- crystallizing the semiconductor grade silicon ingot, optionally also including the melting of the feed silicon material, in a crucible made of silicon nitride, silicon carbide, or a composite of these, optionally coated with a oxide free release coating, - containing the crucible in a sealed hot zone with an inert atmosphere during crystallisation of the ingot, optionally also including the melting of the feed silicon material,
- employing load carrying building elements including heat insulation elements in at least the hot zone which are made of carbon and/or graphite materials, and - employing electric insulating elements in at least the hot zone which are made of silicon nitride, Si3N4. The method according to the first aspect of the invention may be employed for any known process including for crystallising semiconductor grade silicon ingots, including solar grade silicon ingots, such as the Bridgman process or related direct solidification methods, the block-casting process, and the CZ-process for growth of monocrystalline silicon crystals.
In a second aspect of the invention there is provided a device for manufacturing ingots of semiconductor grade silicon, monocrystalline or multicrystalline, comprising a sealed hot zone with an inert atmosphere, where
- all load carrying building elements of the device including heat insulation elements in at least the hot zone are made of carbon and/or graphite materials,
- the electric insulation in at least the hot zone is made of silicon nitride, Si3N4, and
- the crucible is made of either silicon nitride (Si3N4), silicon carbide (SiC), or a composite of these, optionally coated with a oxide free release coating
The term "inert atmosphere" as used herein means an atmosphere in contact with the materials of the device and silicon metal in the hot zone which is essentially chemically inert towards the materials of the device and the silicon metal phase, both in the solid and liquid state. The term as used herein includes any gas pressure of the inert atmosphere, including vacuum.
The device may be any known device for crystallising semiconductor grade silicon ingots, including solar grade silicon ingots, such as furnaces for carrying out the Bridgman process or related direct solidification processes, crystallisation pots for performing the block-casting process, CZ-pullers for performing CZ-growth of monocrystalline silicon crystals.
By using non-oxide materials in the hot zone during the melting and crystallisation of solar grade silicon, the problem with both carbon and oxygen contamination of the silicon metal phase is eliminated/substantially reduced. This will substantially reduce formation of silicon carbide crystals in the metal phase, promoting high solar conversion efficiency of the PV cell made from the wafer. Another factor leading to higher conversion efficiencies is the reduction/avoidance of interstitial recombination-active oxygen complexes. The reduced contamination levels will also give advantages in that the subsequent processing of the silicon metal into solar wafers may be simplified due to absence of hard and brittle inclusions, such as carbides and oxides.
List of figures Figure 1 is a schematic view of a prior art furnace for direct solidification of semiconductor grade ingots. Example of an embodiment of the invention
The invention will be explained in further detail by way of an example of an embodiment of the device for production of multicrystalline silicon ingots. This example should by no means be interpreted as a limitation of the general inventive concept of avoiding carbon and oxygen contamination by avoiding use of oxygen- containing materials in the hot zone. The inventive idea may be employed for any known hot zone where semiconductor grade silicon is being made.
The chosen example is a typical furnace for performing directional solidification of multicrystalline silicon, as shown in Figure 1 which is a facsimile of Fig. 1 of the applicant's International patent application WO 2006/082085. The furnace comprises a gas tight crystallisation chamber defined by insulation walls marked 2 on the figure. An inner chamber is defined by floor 9 with frame 11, walls 10, and lid 5. There is provided suction outlets 24 and injection lance 12 for maintaining an inert atmosphere in the inner chamber. The metal 13 is contained in crucible 1, and the metal 13 is first melted and then subject to a directional solidification by regulating the operation of heating elements 8 and 21, and cooling circuit 4, 15, 16, 17, 19, 20, 22, and 23.
The objective of the invention when applied on this furnace may be obtained by employing a crucible 1 of silicon nitride, silicon carbide, or a composite of these, optionally coated with a oxide free release coating. An example of a suitable silicon nitride crucible is disclosed in NO 317 080, which teaches that a silicon nitride with a total open porosity between 40 and 60 volume% and where at least 50 % of the pores on the surface are larger than the mean diameter of the Si3N4-particles, does not wet liquid silicon such that the crucible will easily slip the solidified metal. However, any crucible made of only silicon nitride and which does not wet liquid silicon may be employed. A pure silicon nitride crucible contains no, or negligible amounts of oxygen/oxides. Thus the migration of oxygen from the crucible to the liquid metal is eliminated, such that interstitial oxygen levels in the solid metal and formation of SiO will be substantially reduced or eliminated. In order to eliminate all oxygen sources in the hot zone, the example of DS-furnace according to the invention employs walls 10, floor 9 with frame 11, lid 5, and lances 24 and 12 made of carbon. Thus there are no oxygen containing elements defining the inner sealed zone of the crystallization chamber, such that both the migration of oxygen into the melt and the formation of CO-gas which comes into contact with melt is practically eliminated.

Claims

1. Method for production of semiconductor grade silicon ingots, where the presence of oxygen in the hot zone is substantially reduced or eliminated by
- crystallizing the semiconductor grade silicon ingot, optionally also including the melting of the feed silicon material, in a crucible made of silicon nitride, silicon carbide, or a composite of these,
- containing the crucible in a sealed hot zone with an inert atmosphere during crystallisation of the ingot, optionally also including the melting of the feed silicon material, - employing load carrying building elements including heat insulation elements in the hot zone which are made of carbon and/or graphite materials, and
- employing electric insulating elements in the hot zone which are made of silicon nitride, Si3N4.
2. Method according to claim 1, where the crucible is coated with a oxide free release coating.
3. Method according to claim 1, where the semiconductor grade crystallisation process is the Bridgman process or a related direct solidification process, the block-casting process, or the CZ-process for growth of monocrystalline silicon crystals.
4. Method according to any of claim 1 to 3, where the formed silicon ingots are solar grade silicon ingots.
5. Device for manufacturing ingots of semiconductor grade silicon, comprising a hot zone with an inert atmosphere, where - all load carrying building elements of the device including heat insulation elements in the hot zone are made of carbon and/or graphite materials,
- the electric insulation in the hot zone is made of silicon nitride, Si3N4, and
- the crucible is made of either of silicon nitride, Si3N4, of silicon carbide, SiC, or a composite of these,
6. Device according to claim 5, where the crucible is coated with a oxide free release coating.
7. A crystallisation furnace for the casting of ingots for multicrystalline wafer production for photovoltaic applications characterised in that all load- carrying and functional components in the hot zone are made from non-oxide materials.
8. A furnace according to claim 5 or 7, where the casting crucible is made from silicon nitride, Si3N4, of silicon carbide, SiC, or a composite of these.
9. A furnace according to claim 5 or 7, where the electrical insulation is made from Si3N4.
PCT/NO2007/000219 2006-06-23 2007-06-20 Device and method for production of semiconductor grade silicon Ceased WO2007148985A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US12/305,908 US20090314198A1 (en) 2006-06-23 2007-06-20 Device and method for production of semiconductor grade silicon
EP07793893A EP2035604A1 (en) 2006-06-23 2007-06-20 Device and method for production of semiconductor grade silicon
JP2009516423A JP2009541193A (en) 2006-06-23 2007-06-20 Apparatus and method for producing semiconductor grade silicon

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US81586006P 2006-06-23 2006-06-23
US60/815,860 2006-06-23

Publications (1)

Publication Number Publication Date
WO2007148985A1 true WO2007148985A1 (en) 2007-12-27

Family

ID=38626564

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2007/000219 Ceased WO2007148985A1 (en) 2006-06-23 2007-06-20 Device and method for production of semiconductor grade silicon

Country Status (7)

Country Link
US (1) US20090314198A1 (en)
EP (1) EP2035604A1 (en)
JP (1) JP2009541193A (en)
KR (1) KR20090024802A (en)
CN (1) CN101495681A (en)
TW (1) TW200806827A (en)
WO (1) WO2007148985A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010033885A1 (en) 2008-09-19 2010-03-25 Memc Electronic Materials, Inc. Directional solidification furnace for reducing melt contamination and reducing wafer contamination
WO2011092659A1 (en) * 2010-01-28 2011-08-04 Memc Singapore Pte, Ltd. Crucible for use in a directional solidification furnace
WO2012143867A1 (en) 2011-04-19 2012-10-26 Rec Wafer Pte. Ltd. An arrangement for manufacturing crystalline silicon ingots
WO2012143385A1 (en) 2011-04-19 2012-10-26 Rec Wafer Pte. Ltd. An arrangement for manufacturing crystalline silicon ingots
EP2711445A1 (en) * 2009-07-16 2014-03-26 MEMC Singapore Pte. Ltd. Multicrystalline silicon ingots with low oxygen concentration
DE102009044390B4 (en) * 2009-11-02 2014-06-26 Hanwha Q.CELLS GmbH Manufacturing method and manufacturing apparatus for producing a semiconductor crystal body
US8784561B2 (en) 2011-03-31 2014-07-22 Memc Singapore Pte. Ltd. (Uen200614794D) Method of adjusting insulation in a directional solidification furnace
EP2492242A4 (en) * 2009-10-19 2015-07-22 Jx Nippon Mining & Metals Corp OVEN FOR MELTING SILICON OR A SILICON-BASED ALLOY
US9435052B2 (en) 2011-04-19 2016-09-06 Rec Solar Pte. Ltd. Arrangement for manufacturing crystalline silicon ingots

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4815003B2 (en) * 2010-03-09 2011-11-16 佑吉 堀岡 Crucible for silicon crystal growth, crucible manufacturing method for silicon crystal growth, and silicon crystal growth method
JP2011201736A (en) * 2010-03-26 2011-10-13 Mitsubishi Materials Corp Method for producing polycrystalline silicon ingot, and polycrystalline silicon ingot
WO2011120598A1 (en) * 2010-03-30 2011-10-06 Rec Wafer Norway As Method for production of semiconductor grade silicon ingots, reusable crucibles and method for manufacturing them
CN101812729A (en) * 2010-04-28 2010-08-25 江西赛维Ldk太阳能高科技有限公司 Polycrystalline silicon ingot with low carbon content and preparation method
DE112014004073B4 (en) * 2013-09-06 2026-04-30 Gtat Corporation Sublimation oven
CN107723798B (en) * 2017-10-30 2020-06-02 中国电子科技集团公司第四十六研究所 Growth device and method for efficiently preparing high-purity semi-insulating silicon carbide single crystal
CN109137067A (en) * 2018-10-30 2019-01-04 浙江羿阳太阳能科技有限公司 A kind of polycrystal silicon ingot pouring device and casting method
CN111912811B (en) * 2020-08-05 2023-07-25 西安奕斯伟材料科技有限公司 Method and device for measuring element content in monocrystalline silicon

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0065122A1 (en) * 1981-05-11 1982-11-24 Toshiba Ceramics Co., Ltd. Device made of silicon nitride for pulling single crystal of silicon and method of manufacturing the same
JPS58181798A (en) * 1982-04-19 1983-10-24 Toshiba Ceramics Co Ltd Manufacture of single crystal silicon
EP0887442A1 (en) * 1997-06-23 1998-12-30 Sharp Kabushiki Kaisha Process and apparatus for producing polycrystalline semiconductor ingot
WO2004016835A1 (en) * 2002-08-15 2004-02-26 Crusin As Mould parts of silicon nitride and method for producing such mould parts
US20040211496A1 (en) * 2003-04-25 2004-10-28 Crystal Systems, Inc. Reusable crucible for silicon ingot growth

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE59801041D1 (en) * 1997-02-06 2001-08-23 Solar Gmbh Deutsche MELTING MATERIALS PROVIDED WITH SILICONE PROTECTIVE LAYERS, A METHOD FOR APPLYING THE SILICONE PROTECTIVE LAYER AND THE USE THEREOF
JP3523986B2 (en) * 1997-07-02 2004-04-26 シャープ株式会社 Method and apparatus for manufacturing polycrystalline semiconductor
US20050126473A1 (en) * 2002-04-02 2005-06-16 Prescott Margaret F. Device for pulling monocrystals

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0065122A1 (en) * 1981-05-11 1982-11-24 Toshiba Ceramics Co., Ltd. Device made of silicon nitride for pulling single crystal of silicon and method of manufacturing the same
JPS58181798A (en) * 1982-04-19 1983-10-24 Toshiba Ceramics Co Ltd Manufacture of single crystal silicon
EP0887442A1 (en) * 1997-06-23 1998-12-30 Sharp Kabushiki Kaisha Process and apparatus for producing polycrystalline semiconductor ingot
WO2004016835A1 (en) * 2002-08-15 2004-02-26 Crusin As Mould parts of silicon nitride and method for producing such mould parts
US20040211496A1 (en) * 2003-04-25 2004-10-28 Crystal Systems, Inc. Reusable crucible for silicon ingot growth

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8317920B2 (en) 2008-09-19 2012-11-27 Memc Singapore Pte. Ltd. Directional solidification furnace for reducing melt contamination and reducing wafer contamination
KR101370180B1 (en) 2008-09-19 2014-03-05 엠이엠씨 싱가포르 피티이. 엘티디. Directional solidification furnace for reducing melt contamination and reducing wafer contamination
CN102159754A (en) * 2008-09-19 2011-08-17 Memc电子材料有限公司 Directional Solidification Furnaces for Reduced Melt Contamination and Reduced Wafer Contamination
JP2012502879A (en) * 2008-09-19 2012-02-02 エムイーエムシー・シンガポール・プライベイト・リミテッド Unidirectional solidification furnace to reduce molten and wafer contaminants
WO2010033885A1 (en) 2008-09-19 2010-03-25 Memc Electronic Materials, Inc. Directional solidification furnace for reducing melt contamination and reducing wafer contamination
CN102159754B (en) * 2008-09-19 2013-07-31 Memc电子材料有限公司 Directional solidification furnace for reducing melt contamination and reducing wafer contamination
US9222196B2 (en) 2008-09-19 2015-12-29 Memc Singapore Pte. Ltd. (Uen200614794D) Directional solidification furnace for reducing melt contamination and reducing wafer contamination
EP2711445A1 (en) * 2009-07-16 2014-03-26 MEMC Singapore Pte. Ltd. Multicrystalline silicon ingots with low oxygen concentration
US9458551B2 (en) 2009-07-16 2016-10-04 Memc Singapore Pte. Ltd. Coated crucibles and methods for applying a coating to a crucible
EP2492242A4 (en) * 2009-10-19 2015-07-22 Jx Nippon Mining & Metals Corp OVEN FOR MELTING SILICON OR A SILICON-BASED ALLOY
DE102009044390B4 (en) * 2009-11-02 2014-06-26 Hanwha Q.CELLS GmbH Manufacturing method and manufacturing apparatus for producing a semiconductor crystal body
WO2011092659A1 (en) * 2010-01-28 2011-08-04 Memc Singapore Pte, Ltd. Crucible for use in a directional solidification furnace
US8784561B2 (en) 2011-03-31 2014-07-22 Memc Singapore Pte. Ltd. (Uen200614794D) Method of adjusting insulation in a directional solidification furnace
US9612054B2 (en) 2011-03-31 2017-04-04 Memc Singapore Pte. Ltd. (Uen200614794D) Methods of adjusting insulation in a directional solidification furnace
WO2012143867A1 (en) 2011-04-19 2012-10-26 Rec Wafer Pte. Ltd. An arrangement for manufacturing crystalline silicon ingots
CN103547712B (en) * 2011-04-19 2016-06-15 瑞科斯太阳能源私人有限公司 Equipment for manufacturing crystalline silicon ingots
US9435052B2 (en) 2011-04-19 2016-09-06 Rec Solar Pte. Ltd. Arrangement for manufacturing crystalline silicon ingots
CN103547712A (en) * 2011-04-19 2014-01-29 Rec沃佛普特有限公司 Equipment for manufacturing crystalline silicon ingots
WO2012143385A1 (en) 2011-04-19 2012-10-26 Rec Wafer Pte. Ltd. An arrangement for manufacturing crystalline silicon ingots

Also Published As

Publication number Publication date
TW200806827A (en) 2008-02-01
KR20090024802A (en) 2009-03-09
JP2009541193A (en) 2009-11-26
CN101495681A (en) 2009-07-29
US20090314198A1 (en) 2009-12-24
EP2035604A1 (en) 2009-03-18

Similar Documents

Publication Publication Date Title
US20090314198A1 (en) Device and method for production of semiconductor grade silicon
JP5815184B2 (en) Ingot and silicon wafer
CN101122047B (en) Method for manufacturing polycrystalline silicon used for solar battery
JP4337954B2 (en) Manufacturing method and manufacturing apparatus for silicon ingot
CN101545135B (en) Method for preparing and purifying solar grade silicon crystal
CN102037163B (en) Method and system for forming a silicon ingot using a low-grade silicon feedstock
US20090208400A1 (en) Method and crucible for direct solidification of semiconductor grade multi-crystalline silicon ingots
JPH11116229A (en) Silicon purification method
JPWO2006059632A1 (en) Method for producing polycrystalline silicon ingot
JP2003277040A (en) Method for purifying silicon and solar cell manufactured using silicon purified by the method
CN102312291A (en) Doped casting monocrystalline silicon and preparation method
WO2011120598A1 (en) Method for production of semiconductor grade silicon ingots, reusable crucibles and method for manufacturing them
WO2003078319A1 (en) Method of purifying silicon, silicon produced by the method and solar cell
GB2479165A (en) Reusable crucible
US20170233887A1 (en) Methods of Producing a Semiconductor with Decreased Oxygen Contamination and Impurities
CN102312290A (en) Doped casting polycrystalline silicon and preparation method
JP2013522160A (en) Silicon purification method
CN101597791A (en) Nitrogen-doped directionally solidified cast polysilicon and its preparation method
US9620664B2 (en) Coating of graphite tooling for manufacture of semiconductors
JP5220935B1 (en) Silicon for solar cell, polycrystalline silicon material, polycrystalline silicon solar cell, and method for producing silicon for solar cell
Ciszek Silicon crystal growth for photovoltaics
TH94340A (en) Equipment and methods for the manufacture of semiconductor grade silicon
JP2013129578A (en) Apparatus for producing silicon, method for purifying silicon, and method for producing polycrystalline silicon ingot

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 200780023487.3

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07793893

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
WWE Wipo information: entry into national phase

Ref document number: 2007793893

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 10491/DELNP/2008

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2009516423

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 1020097001211

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 12305908

Country of ref document: US