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
  • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
  • C30B11/001—Continuous growth
• • 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
  • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
  • C30B11/007—Mechanisms for moving either the charge or the heater
• • 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
  • C30B15/06—Non-vertical pulling
• • 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
  • C30B15/34—Edge-defined film-fed crystal-growth using dies or slits
• • 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
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• • 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

Definitions

• the invention relates to a device for producing a plate of crystalline material by directed crystallization of a liquid phase material in a crucible provided with a bottom, side walls and at least one plate outlet slot, said slot being horizontal and formed in a lower part of a side wall.
• the purpose of the invention is to overcome these drawbacks and in particular to provide a device and a method for manufacturing crystalline material plates by directed crystallization, which is easier to implement and whose rejection of impurities in the liquid phase is more important.
• the crucible has, on its outer surface, in the immediate vicinity of the plate exit slot, electromagnetic means of creation, at least at the level of the slot of plate outlet, magnetic repulsion forces on the liquid phase material, said electromagnetic means being traversed by an alternating current whose frequency is between 1OkHz and 30OkHz.
• FIG. 1 shows a schematic sectional view of a particular embodiment of the device according to the invention.
• FIG. 1 shows a front view of the slot of the device according to Figure 1.
• FIG. 3 shows a schematic sectional view of another particular embodiment of the device according to the invention.
• Figure 4 shows an enlargement of Figure 3, centered on the slot and the magnetic means for creating magnetic forces.
• the device represented in FIGS. 1 and 2 comprises a crucible 1 having a bottom 2 and side walls 3.
• the crucible 1 has a lateral outlet slot 4 arranged horizontally in the lower part of the the right side wall 3 in FIG. 1.
• the crucible 1 is partially filled with a material in the liquid phase 5.
• the exit slot 4 is in communication with the surrounding atmosphere 7 the crucible 1, generally consisting of a neutral gas, such as argon.
• a plate 8 of crystalline material, obtained by directed crystallization of the material in the crucible 1, is drawn through the slot 4.
• the crystalline material is, for example silicon, germanium, gallium arsenide ...
• the thermal gradient inside the crucible 1 is vertical, the temperature decreasing from the top of the crucible 1 to the bottom 2.
• the solidification of the material inside the crucible 1 causes the formation of grain boundaries perpendicular to the plate 8 of solid phase material. This configuration is advantageous for use in photovoltaic devices.
• the directed crystallization of the material preferably takes place at the bottom 2 of the crucible 1 and the solid phase material forming the plate 8 is withdrawn from the bath through the outlet slot 4, as and when it is solidified by any means of appropriate grip not shown in Figure 1.
• the thermal regulation within the crucible 1 is carried out by any means known to maintain, stable and vertical, the thermal gradient in the crucible 1.
• the crucible 1 may advantageously be coupled to a heating system 9, preferably situated above the crucible 1, and to a calorie extraction system 10, preferably located under the crucible 1, in order to maintain the temperature gradient substantially vertical.
• the thermal gradient is, in the crucible 1, substantially perpendicular to the solidification interface.
• the calorie extraction system 10 regulates the heat flux extracted under the material being solidified and the distribution of the heat flow according to the distance to the slot 4.
• the calorie extraction system 10 is, for example, a radiative heat transfer through a transparent bottom 2 of the crucible 1.
• the side walls 3 of the crucible 1 are advantageously coupled to a thermal insulator 11.
• This thermal insulator 11 is preferably placed outside the crucible 1 over the entire surface delimited by the side walls 3. way, there is no heat loss on the side walls 3 and the thermal gradient is maintained substantially vertical.
• the solidification interface of the material is located in the lower part of the crucible 1, preferably near the bottom 2 of the crucible 1. This position is adjusted by means of the thermal gradient in the crucible 1.
• the thickness of the plate 8 thus obtained is essentially defined by the thermal distribution in the crucible 1 and the drawing speed of the plate 8 out of the crucible 1.
• the drawing speed of the plate 8 is preferably located in the range 0.5 - 10 meters / minute.
• the height of the slot 4 is chosen to be greater than the thickness of the plate 8, so as to avoid any mechanical catching and any parasitic solidification during the exit of the plate 8 through the slot 4.
• the device further comprises at least one inductor 6 outside the crucible 1, against the side wall 3, in the immediate vicinity of the exit slot 4.
• the inductor 6 constitutes a preferred embodiment of the electromagnetic means of 6.
• the inductor 6 is traversed by an alternating current having a frequency of between 10kHz and 30OkHz and an intensity, preferably between 100A and 3000A. the inductor 6 thus creates magnetic repulsion forces on the material in the liquid phase 5.
• the inductor 6 may be arranged above or below the slot 4. In the particular embodiment of FIG. 1, two inductors 6 are arranged on either side of the slot 4.
• the interface between the liquid phase material 5 and the atmosphere 7 is in the form of a meniscus 12.
• the latter is preferably situated inside the slot 4, so as to prohibit any exit of the material in the liquid phase. through the slot 4 without disturbing the crystallization of the material in the liquid phase 5 inside the crucible 1.
• the magnetic repulsion forces created by the inductor 6 are adjusted so that the repulsion of the liquid phase material 5 takes place at the exit slot 4, above the plate 8. Repulsion forces also act between the edges of the plate 8 and each lateral end.
• the material in the liquid phase 5 is thus kept inside the crucible 1.
• the amplitude of the current in the inductor 6 is determined as a function of the hydrostatic pressure of the liquid-phase material 5 in the crucible 1 and the distance between the inductor 6 and the meniscus 12.
• the section of the inductor 6 is chosen so as to best concentrate the repulsion forces on the meniscus 12.
• An exemplary embodiment of the device implements an inductor 6 concentrating the currents at about 5 mm from the meniscus 12.
• This inductor allows the retention in the crucible of a silicon height of 5 cm, when it is traversed by a current of 900 A to a frequency of 30Khz.
• the slot 4 has a width of 75mm and a height of 3mm.
• the inductor 6 also causes a stirring effect of the material in the liquid phase 5 close to the slot 4. It creates recirculation loops of the material in the liquid phase 5, which entrain the impurities originating from the solidification interface in the entire material in the liquid phase 5.
• the accumulation of impurities near the solid phase is also reduced compared to the prior art due to the presence of a broader solidification front.
• the stirring effect is favored by the use of a current in the inductor in the low frequency range, for example, of the order of 50 Hz.
• the device therefore preferably comprises means for superimposing at a frequency of between 1 kHz and 300 kHz a frequency favoring stirring in the material in the liquid phase 5.
• two inductors 6 are provided, respectively, traversed by currents of different frequencies.
• a first inductor is then powered by a current having a frequency to ensure the mixing of the material in the liquid phase 5, preferably in the low frequency range, of the order of 50Hz.
• the other inductor is traversed by a current having a frequency between 1OkHz and 300 kHz to ensure the repulsion of the material in the liquid phase 5.
• This simultaneous action can also be performed by a single inductor, for example, by a frequency modulation , amplitude over-modulation, etc.
• the plate 8 of crystalline material consists exclusively of solid phase. Indeed, the material in the liquid phase 5 is pushed back inside the crucible 1 by the inductor 6. The plate 8 is then self-supporting from the outlet of the crucible.
• the material in the liquid phase 5 is brought into contact with a crystallization seed when starting the solidification.
• the crystallization seed is preferably brought into contact with the meniscus 12 to allow the start of crystallization according to predetermined orientations.
• Nucleation / germination centers for example, consisting of localized cold spots, can be added at the interface between the bottom 2 of the crucible 1 and the liquid phase material 5 to facilitate the start of crystallization.
• a treatment device 13 in particular a thermal device, is coupled to the crucible 1 at the exit of the slot 4.
• This device allows the monitoring of a predefined profile of the cooling kinetics of the plate 8. This profile makes it possible to reduce the mechanical stresses and the density of crystalline defects.
• the device 13 can be used to preheat the crystallization seed used at the start of the solidification.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Electromagnetism (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Crystals, And After-Treatments Of Crystals (AREA)
• Silicon Compounds (AREA)
• Crucibles And Fluidized-Bed Furnaces (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Applications Claiming Priority (2)

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• 2007
  • 2007-03-08 FR FR0701701A patent/FR2913434B1/fr not_active Expired - Fee Related
• 2008
  • 2008-03-07 EP EP08775638A patent/EP2132366A2/de not_active Withdrawn
  • 2008-03-07 US US12/449,802 patent/US20100089310A1/en not_active Abandoned
  • 2008-03-07 JP JP2009552248A patent/JP2010523446A/ja active Pending
  • 2008-03-07 WO PCT/FR2008/000304 patent/WO2008132323A2/fr active Application Filing

Non-Patent Citations (1)

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