Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/02—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
  • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
• • 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
  • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
  • C30B13/16—Heating of the molten zone
  • C30B13/20—Heating of the molten zone by induction, e.g. hot wire technique
• • 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
  • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
  • C30B13/16—Heating of the molten zone
  • C30B13/22—Heating of the molten zone by irradiation or electric discharge
• • 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
  • C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
  • C30B13/28—Controlling or regulating
• • 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
  • C30B15/16—Heating of the melt or the crystallised materials by irradiation or electric discharge
• • 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
  • 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
  • C30B35/007—Apparatus for preparing, pre-treating the source material to be used for crystal growth
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
  • B01J2219/0894—Processes carried out in the presence of a plasma
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/60—Compounds characterised by their crystallite size

Definitions

• the invention relates to a method for heat treatment of granules of silicon, which consists of polycrystalline grains, a method for producing a single crystal of silicon, in the course of which heat-treated granules of silicon is used and heat-treated granules of silicon.
• Granules of silicon are usually produced by depositing silicon in a fluidized bed.
• WO 2014/191274 is one of many sources describing the manufacturing process
• the produced granules of silicon consisting of polycrystalline grains can be used directly as a raw material for producing a single crystal.
• a manufacturing method for granules of silicon is proposed in which comparatively little fine dust is obtained and which produces granules of silicon, the polycrystalline grains each having a surface which is relatively smooth.
• the low tendency to dust is a property that becomes particularly important when it is intended to use the granules of silicon to produce a single crystal of silicon.
• the US 2013/0295385 AI discloses a manufacturing method for granules of silicon, which is also used for the production of Single crystals of silicon can be used according to the GFZ process.
• the GFZ process is a modification of the FZ (float zone crystal growth) process in which the single crystal grows at the interface of a melting zone maintained by continued melting of a polycrystalline storage rod by means of an induction heating coil and lowering the growing single crystal.
• FZ float zone crystal growth
• granules of silicon replace the supply rod.
• US 2011/0185963 Al a GFZ process is described in which an induction heating coil extra for melting the granules
• modified GFZ process which has low dislocation rates and can be made with the single crystals of silicon that are as free of gas inclusions as possible.
• Silicon consisting of polycrystalline grains, each comprising: a surface, a peripheral region and a
• the invention is based on the recognition that measures are not sufficient, which are limited to
• Core area (inner area) remains in a solid state. Upon subsequent cooling of the grains crystallizes the
• Granules of silicon suitable for the proposed plasma treatment consist of polycrystalline grains and are preferably produced by depositing silicon onto particles of silicon in the presence of a silicon-containing reaction gas in a fluidized bed reactor.
• the reaction gas contains silane or a chlorine-containing silane, preferably trichlorosilane.
• the method described in WO 2014/191274 AI can be used.
• not less than 98% (by weight) of the granules are grains having a spherical shape whose grain size, expressed by the sieve diameter as the equivalent diameter, is preferably 600 to 8000 ⁇ m, more preferably 600 to 4000 ⁇ m.
• the granules off Silicon preferably contains no more than 50 ppb (by weight) of metallic impurities.
• the granules of silicon may contain chlorine as an impurity.
• Silicon granules of the proposed treatment with plasma also has the effect that the concentration of chlorine in the treated granules of silicon is considerably lower than in the untreated granules of silicon.
• concentration of chlorine in the invention is considerably lower than in the untreated granules of silicon.
• treated granules of silicon may be more than 50%
• the proposed treatment of the granules of silicon with plasma is preferably carried out under a pressure in the range of atmospheric pressure, in particular under a pressure in
• the granules of silicon are preheated in a preheating to a temperature of not less than 900 ° C and then by a
• Transported plasma zone which has a temperature that is above the temperature of the melting point of silicon. A short stay in the plasma zone is already sufficient for the
• the molten area crystallizes again immediately after leaving the plasma zone.
• Such Device for example using a device which is described in DE 103 27 853 AI.
• Such Device comprises a microwave generator, a plasma chamber, microwave conductor for supplying
• Microwave radiation to the plasma chamber and an igniter for igniting the plasma are particularly preferred.
• a device which is described in WO 2015/014839 AI because thus at higher power over the
• Microwave radiation supplied energy in the plasma chamber can be evenly distributed.
• the microwave radiation is preferably introduced at at least two opposite points by waveguides to the plasma chamber.
• the frequency of the microwave radiation is preferably in the range of 0.9 GHz to 10 GHz, for example, 2.45 GHz.
• the plasma zone spreads after ignition of the plasma in the plasma chamber along its longitudinal axis.
• the granules of silicon are preheated by process gas.
• the process gas is passed through the plasma chamber and heated there in the plasma zone itself. Part of the heat absorbed is then transferred to the granules of silicon to preheat it.
• Process gas circulated, so returned after preheating the granules of silicon to a gas inlet into the plasma chamber.
• the process gas is preferably conducted via a lower gas inlet into the plasma chamber and preferably leaves the plasma chamber via an upper gas outlet.
• the process gas is preferably passed tangentially into the plasma chamber at the gas inlet and therefore flows along a swirling manner
• the granules of silicon are allowed to fall through the plasma zone.
• the turbulence of the process gas extends the transport path of the granules of silicon in the Plasma zone and its duration in the plasma zone.
• the inner wall of the plasma chamber consists of a dielectric, preferably of quartz or ceramic. After leaving the plasma chamber, the process gas flows into a preheating stage for granules of silicon and from there preferably back to the gas inlet into the plasma chamber.
• the process gas consists of air or a component of air or a mixture of at least two components of air or of hydrogen or of a mixture of hydrogen and at least one inert gas.
• Preferred process gas has inert or reducing character.
• Particularly preferred process gas is argon or a mixture of argon and
• Hydrogen wherein the proportion of hydrogen should preferably be not more than 2.7% (by volume).
• the preheating stage is preferably a pipe from which the
• Granules of silicon can fall continuously or discontinuously into the plasma zone.
• the granules of silicon are preheated by process gas rising into the tube.
• a heater is present, which additionally heat the tube and the granules of silicon contained therein from the outside. It is particularly preferred to arrange deflecting plates in the tube, which form a cascade of steps, which the
• the tube and optionally the baffles are preferably made of a material through which the
• Granules of silicon on contact not or only slightly contaminated with metals are preferably quartz or ceramic.
• the granules of silicon is conveyed from a reservoir in the preheating and falls against the rising
• Process gas first through the preheating stage, then through the plasma zone and finally to a destination, for example in a collecting container or in a crucible or on a plate or on a conveyor belt.
• the plasma-treated granules of silicon consists of grains with a polycrystalline structure.
• the polycrystalline structure includes a variety of crystals and common ones
• the surface of the grains is smooth and shiny, provided that an inert or reducing gas was used as the process gas and the granules of silicon after the treatment with plasma no oxidizing atmosphere such as
• the edge region extends in each case from the surface of the grains into the interior of the grains. In the edge area, the crystals are much larger than in the core area.
• the crystal density (number of crystals per volume) is smaller in the peripheral area than in the core area.
• the crystal density is preferably not more than 20% of the crystal density in the core region, especially
• the thickness of the peripheral region is preferably not less than 20 ⁇ m, more preferably not less than 40 ⁇ m.
• the special polycrystalline structure of the grains gives the plasma-treated granules of silicon the property of being particularly suitable for the production of single crystals. The potential of the plasma-treated granules of silicon, source of fine dust and gas inclusions to be able to be significantly reduced.
• the plasma-treated granules of silicon are melted and crystallized to a single crystal, without first an oxidizing
• the plasma-treated granules of silicon after leaving the plasma chamber under a non-oxidizing atmosphere, preferably under argon or under a mixture of argon and hydrogen, more preferably under a non-oxidizing atmosphere with the composition of during treatment with Plasma used process gas in a device for
• the device comprises a crucible or a plate. There it will be plasma-treated
• Particle formation is avoided.
• a crystal growing apparatus having an induction heating coil specially provided for melting the granules of silicon.
• Induction heating coil is disclosed for example in US 2011/0185963 AI.
• To produce the melting zone first of all solid silicon, which has an opening in the center of a crucible or
• Granules of silicon due to the treatment with plasma still has a temperature of not less than 600 ° C, more preferably not less than 800 ° C, when it starts to melt the plasma-treated granules of silicon and supply the melt zone. So will the
• Fig.l shows schematically the structure of a device which is suitable to carry out the production of a single crystal of silicon according to a particularly preferred embodiment of the invention.
• 2 shows schematically the construction of a particularly preferred embodiment of the preheating stage.
• 3 schematically shows the structure of a particularly preferred embodiment of the plasma chamber.
• 4 to 8 show SEM images of granules of silicon granules.
• the device according to Fig.l is divided into a device for the treatment of granules of silicon with plasma and a device for producing a single crystal according to the GFZ method using the plasma-treated granules of silicon.
• the device for the treatment of granules of silicon with plasma comprises a reservoir 1 for treatment of granules of silicon, a metering device 2 for metering granules of silicon in a preheating stage 3, in which the granules to be treated is preheated from silicon, a
• Plasma chamber 4 in which a plasma zone 5 is ignited and maintained by microwave radiation, a generator 6 for generating the microwave radiation and a conveyor line 7 for conveying plasma-treated granules 8 of silicon in the device for producing a single crystal according to the GFZ method.
• This facility includes a
• Induction heating coil 9 for melting the granules 8 on a plate 10, wherein the induction coil 9 has an opening through which the granules 8 falls on the plate 10, where it is melted, from there in a molten state through an opening in the center of the plate 10th to get to a melting zone, which is maintained by an induction heating coil 11.
• the melting zone has an interface at which a single crystal 12 grows and is lowered continuously.
• Process gas which leaves the preheating stage 3, is conducted back to a gas inlet into the plasma chamber 4 via a line 17.
• the preheating stage 3 shown schematically in Figure 2 comprises a tube 13 with built-in baffles 14. To be treated granules of silicon is conveyed into an upper region of the tube 13 and initially falls on the baffles 14 and finally, from a lower opening 15 of the tube 13 into the plasma chamber 4. Process gas is directed counter to the falling direction of the granules of silicon from bottom to top through the tube 13.
• the plasma chamber 4 according to Figure 3 comprises waveguide 16 for
• Process gas is
• the section reaches from the surface 22 of the grain into the inside of the grain.
• a near-surface edge region 23 of the grain is through
• FIG. 7 shows a corresponding photograph of a grain of granules of silicon shown in the state before a invention
• the SEM image according to FIG. 8 shows a section of the surface and a section of the cut surface through a grain of granules of silicon which according to the invention has been treated with plasma.
• Edge region 23 of the grain which are comparatively large.
• Granules of silicon containing chlorine as an impurity and having an average grain diameter of 1 mm were in the state after the heat treatment according to the invention with
• the concentration of chlorine was 56% lower in the granules of silicon produced according to the invention than in the comparative granules.

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

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (8)

Family Cites Families (36)

• 2015
  • 2015-08-20 DE DE102015215858.6A patent/DE102015215858B4/de not_active Expired - Fee Related
• 2016
  • 2016-07-01 US US15/742,306 patent/US20180194633A1/en not_active Abandoned
  • 2016-07-01 JP JP2018508631A patent/JP6608041B2/ja not_active Expired - Fee Related
  • 2016-07-01 CN CN201680048555.0A patent/CN107922196A/zh active Pending
  • 2016-07-01 EP EP16733098.4A patent/EP3337758A1/de not_active Withdrawn
  • 2016-07-01 KR KR1020187007609A patent/KR102069984B1/ko active IP Right Grant
  • 2016-07-01 WO PCT/EP2016/065465 patent/WO2017029010A1/de active Application Filing
  • 2016-08-08 TW TW105125161A patent/TWI609999B/zh not_active IP Right Cessation

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