WO1990003952A1 - Procede de production de lingots de silicium par croissance cristalline au moyen d'un bain de fusion rotatif - Google Patents

Procede de production de lingots de silicium par croissance cristalline au moyen d'un bain de fusion rotatif Download PDF

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Publication number
WO1990003952A1
WO1990003952A1 PCT/US1989/004468 US8904468W WO9003952A1 WO 1990003952 A1 WO1990003952 A1 WO 1990003952A1 US 8904468 W US8904468 W US 8904468W WO 9003952 A1 WO9003952 A1 WO 9003952A1
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WIPO (PCT)
Prior art keywords
meltstock
silicon
impurities
crucible
silica
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PCT/US1989/004468
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English (en)
Inventor
Frederick Schmid
Chandra P. Khattak
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Crystal Systems, Inc.
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Publication date
Application filed by Crystal Systems, Inc. filed Critical Crystal Systems, Inc.
Publication of WO1990003952A1 publication Critical patent/WO1990003952A1/fr

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    • 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
    • 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
    • C30B11/008—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method using centrifugal force to the charge

Definitions

  • This invention relates to the manufacture of silicon crystals suitable for use in photovoltaic cells from low purity silicon melt stock.
  • This application is a continuation-in-part of co-pending, co-assigned application United States Serial No. 081,560, filed July 31, 1987 in the names of Frederick Schmid and Chandra P. Khattak which is a continuation of U.S.S.N. 825,960, filed February 4, 1986, which is a continuation of U.S.S.N. 598,828, filed May 10, 1984, which is a continuation of U.S.S.N. 423,170, filed September 24, 1982, which is a continuation of U.S.S.N. 191,260, filed September 26, 1980, all co- assigned and all in the names of Frederick Schmid and Chandra Khattak.
  • the best photovoltaic solar cells have been fabricated from high-purity, single-crystal silicon, the making of which by conventional processes involves many steps.
  • the process begins with metallurgical grade silicon, which is only 98-99% pure. This impurity level inhibits single crystal growth and creates conductivity that is too high for solar cells, owing primarily to the presence of boron and phosphorous.
  • Metallurgical grade silicon is typically produced in large quantities in arc furnaces by the carbothermic reduction of silica. The carbothermic process causes the presence of significant amounts of the impurity of carbon, primarily in the form of silicon carbide. Further, since the silicon is poured in air, the surface of the silicon is oxidized to silica. Additional metallic impurities are present, arising from metals present in the naturally occurring silica.
  • this grade of silicon is then chemically converted by another process to an intermediate compound (e.g., tricholosilane) , which is in turn converted by still another process (e.g., Siemens process) to semiconductor grade silicon (having impurities in the ppb range), which in turn is used to grow a single crystal suitable for use in a solar cell.
  • an intermediate compound e.g., tricholosilane
  • Siemens process e.g., Siemens process
  • semiconductor grade silicon having impurities in the ppb range
  • a method that has proved useful in growing crystals from such resulting high purity silicon is the Heat Exchanger Method, which involves heating material in a crucible to above its melting point in vacuum to melt the material therein and thereafter extracting heat from the bottom of the crucible by providing a heat exchanger in heat conducting relationship with the bottom.
  • the Heat Exchanger Method is described in U.S. Patents Nos. 3,653,432 and 3,898,051 and Applications Serial Nos. 4,465 filed January 18, 1979 and 967,114 filed December 7, 1978, all of which are hereby incorporated by reference.
  • Dow Corning Corporation used specially selected silica and carbon in an arc furnace, and produced metallurgical silicon that is about 99.8% pure, having low concentrations of boron and phosphorous, impurities which have high segregation coefficients and are therefore difficult to segregate during directional crystal solidification.
  • This silicon was poured in air, resulting in a silica layer, which was then etched away. After etching, an ingot was grown by the Czochralski process (a directional solidification process). Loss of single crystallinity still resulted; but growth of a second crystal, using the best portions from the first growth as starting material, enabled the production of a single crystal material suitable for solar cell production.
  • acker, GmbH in West Germany conducts a multiple step process to arrive at raw material for use in crystal growth.
  • This process is described in Dietl, J., "Metallurgical Ways of Silicon Meltstock Processing," ch. 6 of Materials Processing Theory and Practices, Khattak, C. and Ravi, K.(ed.) North-Holland (1987) p. 342.
  • Metallurgical grade silicon is pyrometallurgically upgraded by slagging or, alternatively, by solvent extraction (Al based refining). The resultant is ground and acid leached. An additional pyrometallurgical step by liquid gas extraction is applied.
  • final purification by in situ or additional directional solidification may be applied. After this complicated series of steps, the silicon is finally ready for crystallization.
  • silicon with impurity levels greater than 10,000 ppm by weight e.g., metallurgical grade silicon that is less than 99% pure
  • HEM Heat Exchanger Method
  • Boron impurities are removed in other embodiments where the melt is also stirred or where moist hydrogen is passed through the melt prior to crystal growth. Chlorine is passed through the melt resulting in volatile reaction products and also causing the removal of impurities. The melt is also heated to high temperatures, prior to crystal growing at a lower temperature, to remove impurities with a high vapor pressure by boiling them off.
  • refining is promoted by the expanding area of the solid/liquid interface (as opposed to a constant interface area occurring with directional solidification such as the Czochralski method or a shrinking interface area occurring with casting, when the exterior solidifies before the interior), which increases the impurity concentration on the liquid side of the interface.
  • An impurity increase with known methods can cause deleterious interface breakdown and loss of single crystallinity.
  • the convex to the liquid shape of the solid/liquid interface facilitates removal of SiC particles by the forces from rotation and from rotational deceleration/accelerations.
  • impurities are transported to exterior surfaces where they can be easily cropped off, and the temperature gradient, with the hottest melt at the top, stabilizes temperature gradients.
  • the silica slag layer floats on the surface of the melt and does not interfere with the solid/liquid interface some distance below the interface.
  • the increased turbulence promotes removal of impurities from the interface and their transport to the upper surface.
  • HEM with a high impurity content silicon (such as metallurgical grade silicon) allows further refinement by vaporization of high vapor pressure species.
  • These species are impurities (such as alkali metals, manganese, etc.) that have a tendency to go into vapor phase in preference to staying in the silicon melt.
  • impurities such as alkali metals, manganese, etc.
  • the impurity vapor is continuously removed from the site of the reaction in preference to building up near the melt surface, thereby enhancing removal of these impurities from the melt.
  • the process of the invention removes unwanted impurities from the melt by four processes: 1) vaporization of impurities that is enhanced by vacuum operations eg. alkali metals and group V elements (such as As,P); 2) scavanging and reaction of impurities that is enhanced by slagging with silica and gas blowing, eg. glass forming elements (eg. B, Al, Na), heavy metals (eg. W, Mo, Ti, Zr) and transition metals (eg.
  • Fig. 1 is a schematic view, partially in section, of a crucible, molybdenum retainer, conducting graphite plug, and insulation within the heating chamber of a casting furnace.
  • Fig. 2a is a schematic elevation view of a growing silicon crystal showing detachment of a SiC partial upon deceleration of rotation of the melt.
  • Fig. 2b is a schematic plan view of a growing silicon ingot, showing detachment of a SiC particle upon deceleration of rotation of the melt.
  • Fig. 3 is a schematic view, partially in section, of a crucible suitable for multi-crystalline growth within the heating chamber of a casting furnace.
  • a silica crucible 10 is shown within the cylindrical heating chamber defined by the resistance heater 12 of a casting furnace of the type disclosed in U.S. Patent No. 3,898,051.
  • the crucible 10 rests on a graphite plate 11 which itself is supported by graphite rods 14 mounted on a graphite support plate 16 on turntable 18 at the bottom of the heating chamber, and is surrounded by a cylindrical graphite retainer 9.
  • Crucible 10 is about 6 in. (15 cm.) in height and diameter and its cylindrical wall 22 and base 24 are 0.15 in. (3.7 mm.) thick.
  • Graphite plate 11 is about 0.500 in. (1.25 cm.) thick, and graphite retainer 9, is about 0.250 in. (0.625 cm) thick.
  • a silicon ingot 26, partially solidified according to the process described in aforementioned patents, is shown within the crucible, the convex to the liquid solid-liquid interface 28 having advanced from the seed (shown in dashed lines at 30).
  • a stepped cylindrical graphite plug 50 (upper portion diameter 1.9 in., and lower portion diameter 2.5 in.) extends from turntable 18 upwardly through coaxial holes 52, 54, 56 in, respectively, plate 16, graphite plate 11 and crucible base 24.
  • the top 58 of plug 50 is flush with the inside bottom surface of crucible base 24.
  • the seed 30 is placed over the plug 50 and the adjacent portion of crucible bottom 24 so as to cover opening 56.
  • the exterior of the plug upper portion fits loosely in openings 54, 56 to allow for thermal expansion; and the step 60 between the plug's upper smaller diameter and lower larger diameter portions engages the underside of plate 11.
  • a small quantity of silicon powder is placed in the area of opening 56 where seed 30, crucible 10 and graphite plug 50 are in proximity.
  • Heat exchanger 20 fits within a coaxial recess 62 in the bottom of plug 50, with the top of the heat exchanger about 1/8 in. below the top 58 of the plug.
  • a graphite felt insulation and/or molybdenum heat shield sleeve 64 closely surrounds the larger diameter portion of plug 50, extending axially of the plug the full distance between turntable 18 and plate 11. As shown, the exterior surface of insulation sleeve 64 engages the interior of opening 52.
  • Bearing 70 in the furnace base rotationally supports the entire crucible structure described above, relative to stationary foundation 72.
  • a suitable coupling (not shown) is provided to permit heat exchange from the rotating heat exchanger shaft 20.
  • Heat exchanger 20 is caused to rotate by suitable means, not shown, such as by applying torque to the end of heat exchanger shaft 20.
  • movable silica tube 66 is suspended (by means not shown) so that one end extends into crucible 10 and the other end is connected to a gas supply (not shown) .
  • Etched metallurgical grade silicon is upwardly and outwardly solidified in 6 inch crucible 10 using the Heat Exchanger Method (HEM) .
  • the melt stock is heated under vacuum condition (0.1 torr pressure) .
  • Furnace temperature is increased ' to 100°C above the melt point until the meltstock is melted and reduced to less than 3°C above melting point.
  • the heat exchanger temperature is kept 113°C below the melting point.
  • the heat exchanger temperature is decreased during growth at a rate of 420°C/hr., the furnace temperature is kept constant, and crystal growth lasts about 7.75 hrs.
  • a single crystal ingot with impurities segregated to the outside of the ingot results. Even impurities present in the crystal in the form of solid particles that do not float or sink but remain suspended do not prevent single crystallinity. This is due to the very stable solid/ liquid interface, the low temperature and impurity gradients and to the damping of mechanical vibrations of, and temperature variations in, the heating element by the liquid buffer region between the solid/liquid interface 28 and the crucible wall 22.
  • HEM growth An important feature of HEM growth that is useful in removing impurities from metallurgical grade silicon is that the crystal grows outwardly from the bottom center so that the last regions to solidify are at the upper surface and at the crucible walls. As solidification proceeds, impurities are segregated in front of the solid/liquid interface, causing an increase in impurity concentration in the remaining liquid. Although the increase in impurities concentration in front of the interface causes interface breakdown and loss of single crystallinity in other unidirectional solidification processes, because the HEM interface expands, this impurity buildup is distributed over a larger interface area; hence, concentration buildup is not as rapid as for unidirectional solidification. Therefore, by using the HEM process, higher impurities are tolerated without loss of structure. The impurities are transported to exterior surfaces where they can be easily cropped off.
  • a top view of a growing crystal is shown schematically, with SiC particles at the surface indicated by the symbol "SiC".
  • the particle may be one that would be entrapped in the solid but for the method of the invention.
  • the silicon carbide can be dislodged from the interface by abruptly changing the rate of rotation, e.g., by decelerating the rotation.
  • Fig. 2b depicts the situation where the melt is rotated counter clockwise, as viewed from above. Consequently, all of the SiC particles adhered to the surface rotate in that direction.
  • the SiC particles continue to move in the counter clockwise direction, due to their momentum in that direction. Meanwhile, the solid crystal has decelerated, including those points at which the SiC particles attach. If the deceleration is abrupt enough, the momentum of the particles break the bond to the crystal interface, and the SiC particles continue to move through the melt in the directions indicated by the arrows for the individual particles. Under the influence of its own momentum, a SiC particle continues to move away from the crystal along a tangent to the surface at the point from which it detached. This is shown schematically in Fig. 2a by the arrows at each illustrated SiC particle.
  • the SiC particles come to rest at the outer perimeter of the crucible, and are thereby solidified into the crystal at the outermost surface. They can be easily removed from the surface by cropping or other machining.
  • a suitable rotational velocity depends somewhat on the radius of the crucible. For crucibles on the order of 6 inches (15 cm.) to 36 inches (91 cm), a rotational velocity in the range from 100 revolutions per minute to 5 rpm, respectively, is appropriate. If the melt is decelerated on the order of every one half minute to one minute, the SiC particles will not have a chance to adhere permanently to the interface. Because the detaching force depends on the linear momentum, which depends in part upon the size of the particle, the angular velocity and the radius at which the particle is attached, it is not possible to predetermine an angular deceleration which will detach SiC in every case. However, such deceleration can be easily determined by routine testing.
  • the method is applied advantageously to the growth of ingots having multiple, large-grained crystals.
  • a seed is not used. Growth proceeds from multiple initiation sites on the crucible floor 24.
  • An apparatus suitable for multiple crystal growth is shown in Fig. 3. This apparatus is identical to that of Fig. 1, but for a modification in graphite plug 50'; graphite plate 11' and crucible base 24.
  • crucible base 24' and graphite plate 11* are solid, rather than having concentric openings, and graphite plug 50' is not stepped but rather is flush at the top. The reason for the stepped graphite plug 50 in the single crystal embodiment of Fig.
  • Concentration of the impurities at the solid/liquid interface 28 is also minimized by stirring the melt.
  • Unetched silicon with its adherent silica layer is used to reduce even further the silicon carbide content of the end product.
  • Silica reacts with silicon carbide according to the following reactions: SiC + 2 Si0 2 3 SiO + CO
  • High purity silica powder is also added to the melt stock prior to crystal growth by the HEM to further reduce silicon carbide content by virtue of the above reactions.
  • HEM High purity silica powder
  • 150 grams of silica (99% pure and in powdered form with 100 micrometer particles) is added to 3 kilograms of metallurgical grade silicon.
  • the slag is removed after crystal growth by cropping.
  • the ingot is found to have low enough conductivity to allow use in photovoltaic cells.
  • impurities can be stripped from the melt by passing, via tube 66, gasses that react with the impurities to form reaction products that are volatile or will otherwise remove themselves from the melt.
  • moist hydrogen causes the removal of boron by the formation of boron oxide.
  • chlorine reacts with metallic impurities to form volatile reaction products such as iron chloride.
  • melt stock temperature is increased to 50 to 100°C above the silicon melting point to improve volatization of impurities. After sufficient removal of impurities, the temperature is then lowered to 3°C above melting point to allow crystal growth.

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

Abstract

La présente invention se rapporte à un procédé et à un appareil servant à produire des lingots de silicium d'une structure cristalline sensiblement unique à partir de silicium de qualité métallurgique. Ledit procédé consiste à chauffer le silicium dans un creuset jusqu'à dépasser son point de fusion pour le faire fondre et ensuite à extraire la chaleur du fond du creuset au moyen d'un échangeur de chaleur se trouvant en relation de thermoconduction avec le fond du creuset, puis à mettre le creuset en mouvement et à effectuer la croissance cristalline dans une première direction et à accélérer le mouvement, de façon à détacher de l'interface cristaux/liquide les particules d'impuretés ayant adhéré. Le creuset peut être mis en rotation et l'accélération peut être rotative.
PCT/US1989/004468 1988-10-07 1989-10-05 Procede de production de lingots de silicium par croissance cristalline au moyen d'un bain de fusion rotatif WO1990003952A1 (fr)

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US255,136 1988-10-07

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* Cited by examiner, † Cited by third party
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DE102009034145A1 (de) 2009-07-20 2011-02-03 Schott Solar Ag Vorrichtung und Verfahren zur Herstellung von Ingots aus multikristallinem Silizium
WO2010062735A3 (fr) * 2008-11-03 2011-05-05 Crystal Systems, Inc. Procédé et appareil pour le raffinage de silicium métallurgique en silicium de qualité solaire
CN110565162A (zh) * 2019-09-23 2019-12-13 大同新成新材料股份有限公司 一种多品硅用具有保温结构的热场坩埚及其使用方法
US11441235B2 (en) * 2018-12-07 2022-09-13 Showa Denko K.K. Crystal growing apparatus and crucible having a main body portion and a low radiation portion
US11453957B2 (en) * 2018-12-07 2022-09-27 Showa Denko K.K. Crystal growing apparatus and crucible having a main body portion and a first portion having a radiation rate different from that of the main body portion

Families Citing this family (1)

* Cited by examiner, † Cited by third party
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US5492894A (en) * 1991-03-21 1996-02-20 The Procter & Gamble Company Compositions for treating wrinkles comprising a peptide

Citations (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2912321A (en) * 1956-09-04 1959-11-10 Helen E Brennan Continuous casting and refining of material
US3012865A (en) * 1957-11-25 1961-12-12 Du Pont Silicon purification process
US3265469A (en) * 1964-09-21 1966-08-09 Gen Electric Crystal growing apparatus
US3267529A (en) * 1961-10-04 1966-08-23 Heraeus Gmbh W C Apparatus for melting metals under high vacuum
US3653432A (en) * 1970-09-01 1972-04-04 Us Army Apparatus and method for unidirectionally solidifying high temperature material
US3898051A (en) * 1973-12-28 1975-08-05 Crystal Syst Crystal growing
US3929557A (en) * 1973-06-11 1975-12-30 Us Air Force Periodically and alternately accelerating and decelerating rotation rate of a feed crystal
US4013501A (en) * 1976-05-27 1977-03-22 Bell Telephone Laboratories, Incorporated Growth of neodymium doped yttrium aluminum garnet crystals
US4094731A (en) * 1976-06-21 1978-06-13 Interlake, Inc. Method of purifying silicon
US4097584A (en) * 1976-05-25 1978-06-27 Siemens Aktiengesellschaft Method of producing silicon useful for semiconductor component manufacture
US4193975A (en) * 1977-11-21 1980-03-18 Union Carbide Corporation Process for the production of improved refined metallurgical silicon
US4200671A (en) * 1978-05-05 1980-04-29 The Dow Chemical Company Method for removing paint from a substrate
US4243471A (en) * 1978-05-02 1981-01-06 International Business Machines Corporation Method for directional solidification of silicon
US4247528A (en) * 1979-04-11 1981-01-27 Dow Corning Corporation Method for producing solar-cell-grade silicon
US4256530A (en) * 1978-12-07 1981-03-17 Crystal Systems Inc. Crystal growing
US4298423A (en) * 1976-12-16 1981-11-03 Semix Incorporated Method of purifying silicon
US4312847A (en) * 1979-05-24 1982-01-26 Aluminum Company Of America Silicon purification system
US4551196A (en) * 1981-05-15 1985-11-05 U.S. Philips Corporation Method of growing crystalline cadmium mercury telluride and crystalline cadmium mercury telluride grown by the method
US4643833A (en) * 1984-05-04 1987-02-17 Siemens Aktiengesellschaft Method for separating solid reaction products from silicon produced in an arc furnace
US4659423A (en) * 1986-04-28 1987-04-21 International Business Machines Corporation Semiconductor crystal growth via variable melt rotation
US4793894A (en) * 1987-03-10 1988-12-27 North American Philips Corporation Process for crystal growth from solution
US4837376A (en) * 1986-10-15 1989-06-06 Bayer Aktiengesellschaft Process for refining silicon and silicon purified thereby
US4840699A (en) * 1987-06-12 1989-06-20 Ghemini Technologies Gallium arsenide crystal growth

Patent Citations (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2912321A (en) * 1956-09-04 1959-11-10 Helen E Brennan Continuous casting and refining of material
US3012865A (en) * 1957-11-25 1961-12-12 Du Pont Silicon purification process
US3267529A (en) * 1961-10-04 1966-08-23 Heraeus Gmbh W C Apparatus for melting metals under high vacuum
US3265469A (en) * 1964-09-21 1966-08-09 Gen Electric Crystal growing apparatus
US3653432A (en) * 1970-09-01 1972-04-04 Us Army Apparatus and method for unidirectionally solidifying high temperature material
US3929557A (en) * 1973-06-11 1975-12-30 Us Air Force Periodically and alternately accelerating and decelerating rotation rate of a feed crystal
US3898051A (en) * 1973-12-28 1975-08-05 Crystal Syst Crystal growing
US4097584A (en) * 1976-05-25 1978-06-27 Siemens Aktiengesellschaft Method of producing silicon useful for semiconductor component manufacture
US4013501A (en) * 1976-05-27 1977-03-22 Bell Telephone Laboratories, Incorporated Growth of neodymium doped yttrium aluminum garnet crystals
US4094731A (en) * 1976-06-21 1978-06-13 Interlake, Inc. Method of purifying silicon
US4298423A (en) * 1976-12-16 1981-11-03 Semix Incorporated Method of purifying silicon
US4193975A (en) * 1977-11-21 1980-03-18 Union Carbide Corporation Process for the production of improved refined metallurgical silicon
US4243471A (en) * 1978-05-02 1981-01-06 International Business Machines Corporation Method for directional solidification of silicon
US4200671A (en) * 1978-05-05 1980-04-29 The Dow Chemical Company Method for removing paint from a substrate
US4256530A (en) * 1978-12-07 1981-03-17 Crystal Systems Inc. Crystal growing
US4247528A (en) * 1979-04-11 1981-01-27 Dow Corning Corporation Method for producing solar-cell-grade silicon
US4312847A (en) * 1979-05-24 1982-01-26 Aluminum Company Of America Silicon purification system
US4551196A (en) * 1981-05-15 1985-11-05 U.S. Philips Corporation Method of growing crystalline cadmium mercury telluride and crystalline cadmium mercury telluride grown by the method
US4643833A (en) * 1984-05-04 1987-02-17 Siemens Aktiengesellschaft Method for separating solid reaction products from silicon produced in an arc furnace
US4659423A (en) * 1986-04-28 1987-04-21 International Business Machines Corporation Semiconductor crystal growth via variable melt rotation
US4837376A (en) * 1986-10-15 1989-06-06 Bayer Aktiengesellschaft Process for refining silicon and silicon purified thereby
US4793894A (en) * 1987-03-10 1988-12-27 North American Philips Corporation Process for crystal growth from solution
US4840699A (en) * 1987-06-12 1989-06-20 Ghemini Technologies Gallium arsenide crystal growth

Non-Patent Citations (22)

* Cited by examiner, † Cited by third party
Title
8TH EUROPEAN PHOTOVOLTAIC SOLAR ENERGY CONFERENCE, Florence, Italy, 9-13 May 1988, URBACH, "Important Factors Determining the Removal of SiC from Silicon Employed for the Production of Solar Cells", pages 1-5. *
IEEE TRANSACTIONS ON ELECTRONIC DEVICES, Volume FE-27, No. 4, April 1980, SAITOH et al.: "Impurity gettering of polycrystalline Solar Cells Fabricated from Refined Metallurgical-grade Silicon", pages 671-677. *
JOURNAL OF CRYSTAL GROWTH, 20, 1975, WALD et al.: "Natural and Forced Convention During Solution growth of CdTe by the Traveling Heater Method (THM)", pages 29-36. *
JOURNAL OF CRYSTAL GROWTH, 47, 1979, KURODA et al.: "Growth and Characterization of Polycrystalline Silicon Ingots from Metallurgical Grade Silicon Source", pages 251-260. *
JOURNAL OF CRYSTAL GROWTH, 8, 1971, SHEEL et al.: "Flux growth of Large Crystals by Accelerated crucible rotation technique", pages 304-306. *
MATERIALS PROCESSING THEORY AND PRACTICES, Volume 6, 1987, North Holland Publishing Co, Amsterdam, NL, "Silicon Processing for photovoltaics II", Chapter 6, DEITL, Metallurgical Ways of Silicon Meltstock processing", pages 285-351. *
MATERIALS PROCESSING THEORY AND PRACTICES, Volume 6, 1987, North Holland Publishing Co, Amsterdam, NL, "Silicon Processing for Photovoltaics II", chapter 6, DEITL, Metallurgical Ways of Silicon Meltstock Processing, pages 285-351. *
METALS, Volume 11, June 1978, DOSAJ et al.: "High purity Silicon for Solar Cell Applications", pages 8-13. *
PFANN, WILLIAM G, ZONE MELTING, 2nd Edition, 1978, Robert E. Kripger Publishing Company, Huntington, New York, pages 3-4, 141-142. *
PROCEEDINGS OF THE 11TH CONFERENCE (1979 INTERNATIONAL) ON SOLID STATE DEVICES, TOKYO, 1979; JAPANESE JOURNAL OF APPLIED PHYSICS, Volume 19, (1980), Supplement 19-1, WARABISAKO et al.: "Efficient Solar Cells form Metallurgical Silicon", pages 539-544. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COST POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: HWANG, H.L., "Process and Product Development in Taiwan", pages 233-249. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COSTS POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: AULICH et al., "Solar Grade Silicon Prepared by Carbothermic Reduction of Silicon", pages 267-278. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COSTS POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: DIETHL, J., "Refining of Metallurgical Silicon", pages 251-266. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COSTS POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: NODA, TOSHIO, "Process and Product Development in Japan", pages 213-231. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COSTS POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: RUSTIONI et al., "Solar Silicon from Directional Solidification of MG Silicon produced via the Silicon Carbide Route", pages 292-321. *
PROCEEDINGS OF THE FLAT-PLATE SOLAR ARRAY WORKSHOP ON LOW COSTS POLYSILICON FOR TERRESTIAL PHOTOVOLTAIC SOLAR-CELL APPLICATIONS, 28-30 October 1988, Las Vegas, Nevada, February 1986, Jet Propulsion Laboratory, Pasadena, California: SCHEI, ANDERS, "A Metallurgical Route to Solar-Grade Silicon", pages 279-295. *
PROCEEDINGS OF THE SYMPOSIA ON ELECTRONIC AND OPTICAL PROPERTIES OF POLYCRYSTALLINE OR IMPURE SEMICONDUCTORS AND NOVEL SILICON GROWTH METHODS, May 1980, The Electrochemical Society, Pennington, New Jersey: KHATTAH et al., "Single Crystal Growth of Upgraded Metallurgical Silicon by HEM for Photovoltaic Applications", pages 223-231. *
SOLAR ENERGY MATERIALS 6, 1982, PIZZINI, "Solar Grade Silicon as a Potential Candidate Material for Low Cost Terrestial Solar Cells", pages 253-297. *
SOLAR ENERGY MATERIALS, 6, 1982, North-Holland Publishing Co, PIZZINI, SERGIO, "Solar Grade Silicon as a Potential Candidate Material for Low Cost Terrestial Solar Cells", pages 253-297. *
THIRD E.C. PHOTOVOLTAIC SOLAR ENERGY CONFERENCE, Cannes, France, 27-31 October 1980, D. Reidel Publishing Co. Boston, USA, SCHMIDT et al.: "Directional Solidification of MG Silicon by Heat Exchange Method (HEM) for Photovoltaic Applications", pages 252-256. *
THIRD E.C. PHOTOVOLTAIC SOLAR ENERGY CONFERENCE, Cannes, France, 27-31 October 1980, D. Reidel Publishing Co. Boston, USA; SCHMID et al.: "Directional Solidification of MG Silicon by Heat Exchange Method (HEM) for Photovoltaic Applications", pages 252-256. *
THIRTEENTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 1978, Washington DC, 5-8 June 1978, HANOKA et al., "Efficient polycrystalline Solar Cells Made from Low-Cost Refined Metallurgical Silicon". *

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WO2010062735A3 (fr) * 2008-11-03 2011-05-05 Crystal Systems, Inc. Procédé et appareil pour le raffinage de silicium métallurgique en silicium de qualité solaire
US8329133B2 (en) 2008-11-03 2012-12-11 Gt Crystal Systems, Llc Method and apparatus for refining metallurgical grade silicon to produce solar grade silicon
DE102009034145A1 (de) 2009-07-20 2011-02-03 Schott Solar Ag Vorrichtung und Verfahren zur Herstellung von Ingots aus multikristallinem Silizium
US11441235B2 (en) * 2018-12-07 2022-09-13 Showa Denko K.K. Crystal growing apparatus and crucible having a main body portion and a low radiation portion
US11453957B2 (en) * 2018-12-07 2022-09-27 Showa Denko K.K. Crystal growing apparatus and crucible having a main body portion and a first portion having a radiation rate different from that of the main body portion
CN110565162A (zh) * 2019-09-23 2019-12-13 大同新成新材料股份有限公司 一种多品硅用具有保温结构的热场坩埚及其使用方法
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