US3759670A - Initiating the pulling of a crystalline body from a molten stock - Google Patents

Initiating the pulling of a crystalline body from a molten stock Download PDF

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Publication number
US3759670A
US3759670A US00673304A US3759670DA US3759670A US 3759670 A US3759670 A US 3759670A US 00673304 A US00673304 A US 00673304A US 3759670D A US3759670D A US 3759670DA US 3759670 A US3759670 A US 3759670A
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US
United States
Prior art keywords
seed crystal
stock
crucible
coil
holder
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.)
Expired - Lifetime
Application number
US00673304A
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English (en)
Inventor
Tidt Rummel
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Siemens AG
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Siemens AG
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Publication date
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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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/10—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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/14—Heating of the melt or the crystallised 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
    • 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
    • Y10T117/1068—Seed pulling including heating or cooling details [e.g., shield configuration]

Definitions

  • the invention relates to a method for pulling a crystalline body by a seed crystal fastened in a holder, from a melting stock heated, in a cold coil crucible, at least to melting temperature and to a device for performing said method.
  • This primary coil is charged with high frequency AC, which induces secondary currents in the cold coil crucible. These secondary currents induce secondary currents of their own in the melting stock which is located in the coil crucible and which can thereby be heated to melting temperatures and above.
  • One end of a second crystal, afiixed at the other end within a holder, is brought into contact with the melting stock. The seed crystal is then.
  • the pulling of a monocrystalline body from a molten liquid located in a cold coil crucible has the advantage that the crystallized material has virtually no dislocations. Also, no undesirable impurities reach the melt liquid from the material of the cold coil crucible which is not wetted by the molten mass, and thus cannot penetrate into the crystallized rod.
  • the melting stock in the cold coil crucible is a poorly conducting crystalline material, in its cold state for example, a semiconductor material such as pure silicon, this material must be preheated before it can be heated by the field, issuing from the cold coil crucible. It is known to preheat the stock by irradiating the same with a focused infrared radiation emitted by a projection lamp. During this irradiation, the primary coil which surrounds the cold coil crucible is stressed with high frequency alternating current. After the stock obtains a sufliciently high temperature, through irradiation, it is coupled to the field issuing from the cold coil crucible, and can now be further heated and melted, without the projection lamp.
  • the invention has as its object to remedy this condition so as to heat the largest possible part of the stock to be melted, situated in the cold coil crucible by the field which issues from the coil crucible, prior to melting said stock so that the process is considerably accelerated.
  • the objective is achieved according to the invention, by heating the seed crystal at one end by a heating device, approaching the heated end of the seed crystal to the stock to be melted, whereby the latter may be heated and that thereupon heating the stock by the field, issuing from the cold coil crucible.
  • the heated end of the crystal seed brought into contact with the melting stock. It is also advantageous to heat the seed crystal at one end, at least to melting temperature.
  • the crystal seed may also consist of a material which is of poor conductivity at low temperatures
  • a device for heating the seed crystal.
  • This device comprises an induction coil and a preheating body which may be coupled to the field of the induction coil and which is is a readily conducting material.
  • This type of heating device may preheat the seed crystal with the aid of the preheating body, for example, at the end which is clamped into the holder. Thereafter, an incandescence zone, which is heated by the induction coil, is moved, starting at the preheated end, through a relative movement between the seed crystal and the induction coil, to the free end of the seed crystal which is then brought close to the melting stock or brought into contact with the melting stock.
  • the basket-type silver crucible 2 shown in the figure, comprises two half-rings 3a and 3b, with tubes 4:: and 4b placed at their bottom, which run together at their ends. These tubes 4a and 4b are interconnected at their bottom end through a central portion 5, with channels which run together and to which tubes 4a and 4b are attached. Within the rings halves 3a and 3b are hollow spaces, within which the hollow spaces of the tubes 4a and 4b, end.
  • the basket-type silver crucible 2 is suspended, within a recipient, not shown in the drawing, which is either evacuated or filled with protective gas, from two hollow tubes 6 and 7.
  • the hollow spaces of these tubes end at the hollow spaces of the ring halves 3a and 3b. Cooling water flows through tube 6, thence into the basket-type crucible 2 and leaves the same through the other tube 7, after having traversed ring half 3a, the tubes 4a, the central portion 5, the tubes 4b and the ring half 3b.
  • the outer wall of the basket-type crucible 2 is enclosed by a primary coil 8, which is also situated in the notillustrated recipient and is connected to a high frequency generator, not shown.
  • the basket-shaped silver crucible 2 contains as the melting stock, a piece of solid, highly pure silicon 9, which attains this high electrical conductivity only at a temperature of about 600 C. so that the electromagnetic field issuing from the silver crucible 2 and induced through primary coil 8, becomes coupled to the silicon piece 9.
  • holder 10 Above the opening of the silver crucible 2, is holder 10 on shaft 19, wherein an elongated seed crystal 11 of silicon is affixed. Also, above the opening of the basket-type crucible 2 is another shaft 12 at whose lower end is arranged an induction coil 13 traversed by a coolant, for example, water. The shafts 19 and 12 are displaceable in axial direction, as indicated by the double arrow.
  • the holder consists of electricity conducting steel.
  • the seed crystal 11 attached in the holder 10 Prior to the pulling process, the seed crystal 11 attached in the holder 10, is pushed through the induction coil 13 and the induction coil 13 is brought so close to the holder 10, that the coil field becomes coupled to holder 10. Thereupon, the induction coil 13 is stressed with high frequency alternating current, and the holder 10 and thus also the end of the crystal seed 11 clamped thereinto, are heated to a temperature of about 600 C. Thus. a preheated zone of increased electrical conductivity develops in the seed crystal 11, in the vicinity of the holder 10. The preheated zone is coupled to the field issuing from the induction coil 13. A relative movement between the coil 13 and the seed crystal 11, causes the preheated zone of increased electrical conductivity in the seed crystal 11, to move toward the end of the seed crystal.
  • the induction coil 13 is so strongly Stressed with energy that the lower end of the seed crystal 11 melts.
  • the coil 13 and the seed crystal 11 are now moved so far downward until the molten drop contacts the to be molten stock 9, consisting of cold silicon.
  • a region of several cubic centimeters is heated in the stock 9, to a temperature of at least 600 C.
  • the field issuing from the baskettype silver crucible 2 becomes coupled, so that gradually, the entire stock 9 is molten through the energy, supplied to primary coil 8, and is heated thereby.
  • the current supply to the induction coil 13 is interrupted and the induction coil 13 is shifted axially to the holder 10.
  • the holder 10 is removed together with the coil 13, axially upward, and a rod-shaped crystal growing at the lower end of the seed crystal 11, is pulled from the molten silicon, in the basket-shaped silver crucible 2.
  • the energy supply to the induction coil 13 may be disconnected immediately after the crystal seed 11 and the solid molten stock 9, are brought into contact.
  • a separate preheating device which may be coupled to the induction coil 13, may be located beneath the holder 10, such as a molybdenum ring across which the induction coil 13 may be so pushed that the ring will not cause interturn short circuit.
  • the silicon, in the silver crucible 2, may weigh several hundred grams while the monocrystalline silicon seed crystal 11 has a diameter of 4 mm.
  • the power of the induction coil 13 is, in this case, about 2 kv.
  • the frequency of the high frequency AC current, with which the primary coil 8 is charged, is within the range of 0.5 to 1 mHz., while the output of the coil 8 is about 60 kw.
  • the crucible 2 is specifically described as being silver, it can also be copper, as previously mentioned.
  • a method for pulling a crystalline body by a seed crystal fastened in a holder from a melting stock heated, in a cooled, multiwinding induction heating coil crucible, at least to melting temperature which comprises heating inductively, said holder and adjacent end of the seed crystal by an inductive heating device, utilizing said holder to facilitate developing a preheated zone of increased electrical conductivity in said heated end of said seed crystal, providing relative movement between said inductive heating device and said seed crystal, moving said preheated zone of increased electrical conductivity toward the other end of said seed crystal, approaching the heated end to the stock to be molten, whereby heat from the seed crystal heats the stock to a temperature at which said stock is conductive, and thereafter heating said stock by the field issuing from the cooled multiwinding coil crucible.
  • Apparatus for pulling a crystalline body from a melting stock which comprises a cooled, multiwinding induction heating coil crucible, an induction coil surrounding said crucible, a seed crystal holder above the opening of said crucible, a seed crystal in said seed crystal holder, a movable induction coil surrounding said seed crystal and initially disposed about the end of said seed crystal adjacent to said holder whereby said moveable induction coil heats said holder and a preheated zone of increased electrical conductivity is developed in the end of said seed crystal adjacent to said holder, said moveable induction coil being moveable relative to said seed crystal so that said preheated zone of increased electrical conductivity is first moved to the other end of said seed crystal to melt said other end of said seed crystal and means to subsequently approach the said other end of the seed crystal with the stock in the crucible to be molten.

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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)
  • Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
US00673304A 1969-09-24 1970-09-18 Initiating the pulling of a crystalline body from a molten stock Expired - Lifetime US3759670A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691948194 DE1948194A1 (de) 1969-09-24 1969-09-24 Verfahren zum Ziehen eines kristallinen Koerpers aus einem mindestens auf die Schmelztemperatur erhitzten Schmelzgut und Vorrichtung zur Durchfuehrung dieses Verfahrens

Publications (1)

Publication Number Publication Date
US3759670A true US3759670A (en) 1973-09-18

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US00673304A Expired - Lifetime US3759670A (en) 1969-09-24 1970-09-18 Initiating the pulling of a crystalline body from a molten stock

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US (1) US3759670A (US08177716-20120515-C00003.png)
AT (1) AT309390B (US08177716-20120515-C00003.png)
BE (1) BE756590A (US08177716-20120515-C00003.png)
CH (1) CH534541A (US08177716-20120515-C00003.png)
DE (1) DE1948194A1 (US08177716-20120515-C00003.png)
DK (1) DK124175B (US08177716-20120515-C00003.png)
FR (1) FR2062437A5 (US08177716-20120515-C00003.png)
GB (1) GB1284068A (US08177716-20120515-C00003.png)
NL (1) NL7010531A (US08177716-20120515-C00003.png)
SE (1) SE368663B (US08177716-20120515-C00003.png)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049384A (en) * 1975-04-14 1977-09-20 Arthur D. Little, Inc. Cold crucible system
US4224100A (en) * 1978-06-16 1980-09-23 Litton Systems, Inc. Method and apparatus for making crystals
US4259278A (en) * 1979-07-09 1981-03-31 Ultra Carbon Corporation Method of reshaping warped graphite enclosures and the like
US4849598A (en) * 1987-03-30 1989-07-18 Honda Giken Kogyo Kabushiki Kaisha Method of and apparatus for baking coating layer utilizing electrical induction and eddy currents
US5885344A (en) * 1997-08-08 1999-03-23 Memc Electronic Materials, Inc. Non-dash neck method for single crystal silicon growth

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3316547C2 (de) * 1983-05-06 1985-05-30 Philips Patentverwaltung Gmbh, 2000 Hamburg Kalter Tiegel für das Erschmelzen nichtmetallischer anorganischer Verbindungen
AT385059B (de) * 1983-05-31 1988-02-10 Avl Verbrennungskraft Messtech Verfahren zum zuechten von kristallen, insbesondere einkristallen sowie vorrichtung zur durchfuehrung des verfahrens
JPH04331792A (ja) * 1991-04-30 1992-11-19 Osaka Titanium Co Ltd シリコン単結晶製造方法

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4049384A (en) * 1975-04-14 1977-09-20 Arthur D. Little, Inc. Cold crucible system
US4224100A (en) * 1978-06-16 1980-09-23 Litton Systems, Inc. Method and apparatus for making crystals
US4259278A (en) * 1979-07-09 1981-03-31 Ultra Carbon Corporation Method of reshaping warped graphite enclosures and the like
US4849598A (en) * 1987-03-30 1989-07-18 Honda Giken Kogyo Kabushiki Kaisha Method of and apparatus for baking coating layer utilizing electrical induction and eddy currents
US5885344A (en) * 1997-08-08 1999-03-23 Memc Electronic Materials, Inc. Non-dash neck method for single crystal silicon growth

Also Published As

Publication number Publication date
AT309390B (de) 1973-08-10
DK124175B (da) 1972-09-25
GB1284068A (en) 1972-08-02
DE1948194A1 (de) 1971-04-01
BE756590A (fr) 1971-03-24
FR2062437A5 (US08177716-20120515-C00003.png) 1971-06-25
SE368663B (US08177716-20120515-C00003.png) 1974-07-15
CH534541A (de) 1973-03-15
NL7010531A (US08177716-20120515-C00003.png) 1971-03-26

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