Abstract: A cylinder assembly of a single crystal pulling apparatus and a single crystal pulling apparatus are provided in the present disclosure. The cylinder assembly includes an inner cylinder, an outer cylinder, an annular plate and a sleeve. The inner cylinder has a shape of inverted conical. An upper end of the inner cylinder is connected to an upper end of the outer cylinder. A lower end of the outer cylinder is hermetically connected to an outer edge of the annular plate. A lower end of the inner cylinder is fixedly connected to an upper surface of the annular plate. The sleeve passes through and is fixed in an annular opening of the annular plate.

Abstract: [Object] To provide a thin plate-shaped single-crystal production equipment and a thin plate-shaped single-crystal production method that can produce a thin plate-shaped single crystal having a uniform dopant concentration at an optimum chemical composition and a thickness of several hundreds of micrometers continuously at low cost with high precision even when the single crystal is a single crystal of an incongruent melting material or a solid solution material or a single crystal of a congruent melting material.

Abstract: An assembly sleeve of a single crystal pulling apparatus, and the single crystal pulling apparatus are provided. The assembly sleeve includes inner and outer cylinders and a bottom cylinder. The outer cylinder is provided with openings at both ends and sleeved onto the inner cylinder. The bottom cylinder is arranged at the opening at a lower end of the outer cylinder, and includes an annular plate and a lower cylinder. Each of the inner lower cylinders is of an inverted-cone shape, an upper end of the inner cylinder is connected to an upper end of the outer cylinder, an outer edge of the annular plate is hermetically connected to the lower end of the outer cylinder, an inner edge of the annular plate is connected to an upper end of the lower cylinder, and a lower end of the inner cylinder is fixedly connected to an upper surface of the annular plate.

Abstract: Methods for growing a single crystal silicon ingot are disclosed. A dynamic state chart that monitors a plurality of ingot growth parameters may be produced and used during production of single crystal silicon ingots. In some embodiments, the dynamic state chart is a dynamic circle map chart having a plurality of sectors with each sector monitoring an ingot growth parameter.

Abstract: Methods for growing a single crystal silicon ingot are disclosed. A dynamic state chart that monitors a plurality of ingot growth parameters may be produced and used during production of single crystal silicon ingots. In some embodiments, the dynamic state chart is a dynamic circle map chart having a plurality of sectors with each sector monitoring an ingot growth parameter.

Abstract: Annealed wafers having reduced residual voids after annealing and reduced deterioration of TDDB characteristics of an oxide film formed on the annealed wafer, while extending the range of nitrogen concentration contained in a silicon single crystal, are prepared by a method wherein crystal pulling conditions are controlled such that a ratio V/G between a crystal pulling rate V and an average axial temperature gradient G is ?0.9×(V/G)crit and ?2.5×(V/G)crit, and hydrogen partial pressure is ?3 Pa and ?40 Pa. The silicon single crystal has a nitrogen concentration of >5×1014 atoms/cm3 and ?6×1015atoms/cm3, a carbon concentration of ?1×1015 atoms/cm3 and ?9×1015 atoms/cm3, and heat treatment is performed in a noble gas atmosphere having an impurity concentration of ?5 ppma, or in a non-oxidizing atmosphere.

Abstract: Embodiments related to sheet production are disclosed. A melt of a material is cooled to form a sheet of the material on the melt. The sheet is formed in a first region at a first sheet height. The sheet is translated to a second region such that it has a second sheet height higher than the first sheet height. The sheet is then separated from the melt. A seed wafer may be used to form the sheet.

Abstract: A method for manufacturing a silicon single crystal is provided including producing a silicon melt in a chamber by melting a silicon raw material loaded into a silica glass crucible under a reduced pressure and high temperature, removing gas bubbles from within the silicon melt by rapidly changing at least the pressure or temperature within the chamber, and pulling up the silicon single crystal from the silicon melt after the gas bubbles are removed. When the pressure is rapidly changed, the pressure within the chamber is rapidly changed at a predetermined change ratio. In addition, when the temperature is rapidly changed, the temperature within the chamber is rapidly changed at a predetermined change ratio. In this way, Ar gas attached to an inner surface of the crucible and h is the cause of the generation of SiO gas is removed.

Abstract: An apparatus and method of manufacturing a crystal grower is disclosed. The crystal growing apparatus includes a receptacle constructed to receive a material selected to grow a crystal and an induction heater constructed to heat the material, with the induction heater comprising a Litz coil and a hose constructed to receive the Litz coil therein. The hose further comprises an inner liner formed of an electrically non-conductive material, a reinforcement layer surrounding the inner liner to provide structural reinforcement thereto, and an outer liner applied about the reinforcement layer to form an exterior of the hose.

Abstract: Apparatus and method for a crucible-less production of silicon ingots, wherein a support with a seed layer and a liquid layer is gradually lowered in a temperature field with a vertical gradient to solidify the liquid layer in a controlled way.

Abstract: The present invention relates to a method for manufacturing an ultra low defect semiconductor single crystalline ingot, which uses a Czochralski process for growing a semiconductor single crystalline ingot through a solid-liquid interface by dipping a seed into a semiconductor melt received in a quartz crucible and slowly pulling up the seed while rotating the seed, wherein a defect-free margin is controlled by increasing or decreasing a heat space on a surface of the semiconductor melt according to change in length of the single crystalline ingot as progress of the single crystalline ingot growth process.

Abstract: The invention relates to a method of fabricating at least one polycrystalline silicon plate (68, 70) with one (64, 66) of its two faces presenting predetermined relief, in which method a layer of polycrystalline silicon (60, 62) is deposited on at least one (56, 58) of the two faces of a support (50). The method comprises the steps of embossing said face (52, 54) of the support (50) to impart thereto a shape that is complementary to said relief; depositing said polycrystalline silicon layer (60, 62) on said embossed face (56, 58) of the support (50), the surface (64 or 66) of said polycrystalline silicon layer situated in contact with said embossed face (56 or 58) then taking on the shape of said relief; and eliminating said support in order to obtain said polycrystalline silicon plate (68 or 70). The invention is applicable to fabricating solar cells.

Abstract: A device for pulling a single crystal from a melt having a widened portion between an upper and a lower neck portion including a pulling device having a pulling device cable drum configured to wind a pulling cable, the pulling cable configured to pull the single crystal and a supporting device configured to relieve the upper neck portion of a weight of the single crystal.

Abstract: In this method for manufacturing a silicon single crystal, when growing the silicon single crystal, in order to control the V/G value with high accuracy so as to yield a desired defect-free region, it is important to conduct the pulling at a constant pulling rate. In the method for pulling a silicon single crystal in the present invention, in order to control the V/G value with high accuracy, the distance ?t between the melt surface of the silicon melt and the heat shielding member that is disposed so as to oppose to and to partially cover this melt surface is continuously measured while pulling (growing) the silicon single crystal.

Abstract: A velocity of Ar gas flow passing through between a lower end of a cylindrical body and a thermal shielding body is influenced by arrangement of a pulling path of single crystal silicon, a cylindrical body, and a thermal shielding body. Accordingly, the velocity of the Ar gas flow passing through between a lower end of the cylindrical body and the thermal shielding body is controlled by adjusting a relative position of the pulling path of the single crystal silicon, the cylindrical body, and the thermal shielding body. As described above, dust falling off to silicon melt can be reduced, thereby preventing deterioration in quality of the single crystal silicon.

Abstract: Provided is a method for reliably and easily measuring a liquid level by selecting an optimal reflection method from among a plurality of reflection methods, depending on growing conditions of a pulled single crystal. The method comprises: setting a plurality of measuring methods having different ways of determining the liquid level; creating, in advance, information that associates with a gap between the outer peripheral face of the single crystal and a predetermined position located between a heat shield and the outer peripheral face of the single crystal; determining the gap in accordance with manufacturing conditions; selecting a measuring method associated to the determined gap, on the basis of the information; and measuring the liquid level of a melt surface in use of the selected measuring method.

Abstract: A single-crystal manufacturing apparatus comprises a chamber, a crucible in the chamber, a heater arranged around the crucible, a lifting mechanism for lifting a seed crystal, and a guide passage for the seed crystal and a grown single crystal. In the single-crystal manufacturing apparatus, a material polycrystal contained the crucible is melted by a heater, and the seed crystal is made to contact the molten polycrystal and is lifted. The single-crystal manufacturing apparatus comprises a cylindrical quartz tube having a curved bottom portion, and a dome-shaped quartz plate. The curved bottom portion faces the crucible from the upper portion of the chamber through the guide passage. The quartz plate is arranged to enclose the quartz tube. The quartz tube has a reflecting structure for reflecting a heat ray from at least its bottom portion whereas the quartz plate has a reflecting structure for reflecting the heat ray to the crucible.

Abstract: An upper heater for use in the production of a single crystal, the upper heater having electrodes to which a current is supplied and a heat generating section which generates heat by resistance heating are provided, the upper heater being used when a single crystal is produced by a Czochralski method, the upper heater being placed above a graphite heater which is placed so as to surround a crucible containing silicon melt, wherein the heat generating section is ring-shaped and is placed so as to surround the crucible, and has slits formed from the inside and the outside of the heat generating section in a horizontal direction. As a result, the upper heater controls a crystal defect of the single crystal efficiently and improves the oxygen concentration controllability.

Abstract: A weir is extended vertically to define an optimal annular gap between the top of the weir and the underside of a super-adjacent heat shield. The annular gap provides a high velocity stream of argon gas to be directed from the growth region to the melt region to substantially eliminate the transport of airborne particles from the melt region to the growth region. The tall weir may be configured as a modular, reusable weir extension supportably engaged with an outer (and/or inner) weir.

Abstract: A single-crystal manufacturing apparatus comprising at least: a main chamber configured to accommodate a crucible; a pulling chamber continuously provided above the main chamber, the pulling chamber into which a grown single crystal is pulled and accommodated; a gas inlet provided in the pulling chamber; a gas flow-guide cylinder downwardly extending from a ceiling of the main chamber; and a heat-insulating ring upwardly extending from a lower end portion of the gas flow-guide cylinder with a diameter of the heat-insulating ring increased so as to surround an outside of the gas flow-guide cylinder, wherein at least one window is provided in a region between 50 and 200 mm from a lower end of the gas flow-guide cylinder, and an opening area of the window accounts for 50% or more of a surface area of the region between 50 and 200 mm from the lower end of the gas flow-guide cylinder.

Abstract: A device and method for producing Ga doped silicone single crystal with a diameter between 150 and 165 mm and a narrow resistivity distribution range (from 3 ?·cm to 0.5 ?·cm). The device is characterized by the use of a shorter heater and a funnel shaped gas flow guide capable of blowing an inert gas such as Ar straight to the crystallization frontier at the interface between outer surface of the nascent single crystal ingot and the surface of the melt of polycrystalline silicone raw materials in a quartz crucible.

Abstract: A method of purifying substances is described herein, particularly suitable for purifying silica and forming it into silicon oxide sheets or ribbons, or silicon sheets or ribbons. The method includes ion sweeping a sheet of a substance containing ionic impurities by providing an ionic driving force and a thermal driving force. Ions are swept to a collectable region of the sheet. A system is also provided for purifying substances including an ion sweeping sub-system for providing an ionic driving force to a sheet or ribbon, and a heating sub-system positioned and configured for heating the sheet or ribbon. Impurities swept to an edge, surface or both are then mechanically or chemically removed.

Abstract: A method of growing hexagonal boron nitride single crystal is provided. Hexagonal boron nitride single crystal is grown in calcium nitride flux by heating, or heating and then slowly cooling, boron nitride and a calcium series material in an atmosphere containing nitrogen. Bulk hexagonal boron nitride single crystal can thereby successfully be grown.

Abstract: A melter assembly supplies a charge of molten source material to a crystal forming apparatus for use in forming crystalline bodies. The melter assembly comprises a housing and a crucible located in the housing. A heater is disposed relative to the crucible for melting solid source material received in the crucible. The crucible has a nozzle to control the flow of molten source material such that a directed flow of molten source material can be supplied to the crystal forming apparatus at a selected flow rate.

Abstract: An apparatus and method of manufacturing a crystal grower is disclosed. The crystal grower includes a reservoir constructed to receive a crystal growing material therein. An induction heater having a coil of woven strands of wire is disposed proximate the reservoir and heats the crystal growing material.

Abstract: A capsule for containing at least one reactant and a supercritical fluid in a substantially air-free environment under high pressure, high temperature processing conditions. The capsule includes a closed end, at least one wall adjoining the closed end and extending from the closed end; and a sealed end adjoining the at least one wall opposite the closed end. The at least one wall, closed end, and sealed end define a chamber therein for containing the reactant and a solvent that becomes a supercritical fluid at high temperatures and high pressures. The capsule is formed from a deformable material and is fluid impermeable and chemically inert with respect to the reactant and the supercritical fluid under processing conditions, which are generally above 5 kbar and 550° C. and, preferably, at pressures between 5 kbar and 80 kbar and temperatures between 550 ° C. and about 1500° C.

Abstract: An apparatus and method for producing a crystalline ribbon continuously from a melt pool of liquid feed material, e.g. silicon. The silicon is melted and flowed into a growth tray to provide a melt pool of liquid silicon. Heat is passively extracted by allowing heat to flow from the melt pool up through a chimney. Heat is simultaneously applied to the growth tray to keep the silicon in its liquid phase while heat loss is occurring through the chimney. A template is placed in contact with the melt pool as heat is lost through the chimney so that the silicon starts to “freeze” (i.e. solidify) and adheres to the template. The template is then pulled from the melt pool thereby producing a continuous ribbon of crystalline silicon.

Abstract: A method for producing a single crystal by pulling a single crystal from a raw material melt in a chamber according to the Czochralski method, including pulling a single crystal having a defect-free region, which is outside an OSF region, to occur in a ring shape in the radial direction, and in which interstitial-type and vacancy-type defects do not exist. The pulling of the single crystal is controlled so that an average cooling rate in passing through a temperature region of the melting point of the single crystal to 950° C. is in the range of 0.96° C./min or more, an average cooling rate in passing through a temperature region of 1150° C. to 1080° C. is in the range of 0.88° C./min or more, and an average cooling rate in passing through a temperature region of 1050° C. to 950° C. is in the range of 0.71° C./min or more.

Abstract: A method of servicing multiple crystal forming apparatus with a single melter assembly is provided. The method includes the steps of positioning the melter assembly relative to a first crystal forming apparatus for delivering molten silicon to a crucible of the first apparatus. A heater in the melter assembly is operated to melt source material in a melting crucible. A stream of molten source material is delivered from the melter assembly to the first crystal forming apparatus. The melter assembly is positioned relative to a second crystal forming apparatus for delivering molten silicon to a crucible of the second apparatus. A stream of molten source material is transferred from the melter assembly to the second crystal forming apparatus.

Abstract: Small crystals are made by mixing a solution of a desired substance with an anti-solvent in a fluidic vortex mixer in which the residence time is less than 1s, for example 10 ms. The liquid within the fluidic vortex mixer (12) is subjected to high intensity ultrasound from a transducer (20, 22). The solution very rapidly becomes supersaturated, and the ultrasound can induce a very large number of nuclei for crystal growth. Small crystals, for example less than 5 ?m, are formed. The resulting suspension is treated so as to add or remove ingredients, and then spray dried using an atomizer tuned to create small droplets in such a way that each droplet should contain not more than one crystal. Crystal agglomeration is hence prevented.

Abstract: The invention is directed to apparatus and methods for measuring and for reducing dust in granular polysilicon. In one aspect, a system includes a process vessel having a vacuum port for pulling dust from the polysilicon. Another system of the invention includes a baffle tube for receiving a polysilicon flow. A measuring system includes a manifold and filter for separating and measuring the dust from a flow of polysilicon. The invention is also directed to methods of using the systems, to methods of manufacturing and packaging granular polysilicon, and to a supply of granular polysilicon.

Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of geometrically ordered multi-crystalline silicon may be formed that is free or substantially free of radially-distributed impurities and defects and having at least two dimensions that are each at least about 10 cm is provided.

Abstract: Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.

Abstract: The disclosure relates to an apparatus and a method for producing a single crystal of semiconductor material. The apparatus comprises a chamber and a crucible which is arranged in the chamber and is enclosed by a crucible heater, a radiation shield for shielding a growing single crystal and thermal insulation between the crucible heater and an inner wall of the chamber. The apparatus may include a resilient seal which seals a gap between the inner wall and the thermal insulation and forms an obstacle for the transport of gaseous iron carbonyls to the single crystal. The disclosure also relates to a method for producing a single crystal of semiconductor material by using the apparatus, the single crystal which is produced and a semiconductor wafer cut therefrom.

Abstract: In a method for producing a high quality silicon single crystal by the Czochralski method, a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part and a circumferential part, and the temperature gradient of the central part and the temperature gradient of the circumferential part are separately controlled. When a silicon melt located at a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part melt and a circumferential part melt, the method controls the temperature gradient of the central part melt by directly controlling the temperature distribution of a melt and indirectly controls the temperature gradient of the circumferential part melt by controlling the temperature gradient of the single crystal, thereby effectively controlling the overall temperature distribution of the melt, thus producing a high quality single crystal ingot free of defects with a high growth velocity.

Abstract: The process for growing single crystals, wherein crystal material is melted in a crucible and a crystal nucleus is immersed in the molten crystal material and slowly pulled out, wherein the crystal formed during the pulling is kept at a temperature close to melting temperature of the output material. The invention also includes a device for practicing the above process.

Abstract: For producing ultra pure materials a first station has a porous gas distributor. A material supply supplies material to the porous gas distributor. A gas source supplies gas to the distributor and through the distributor to the material in contact with the distributor. A heater adjacent the porous gas distributor heats and melts the material as gas is passed through the material. Dopant and a treatment liquid is or solid supplied to the material. Treated material is discharged from the first station into a second station. A second porous gas distributor in the second station distributes gas through the material in the second station. A crucible receives molten material from the second station for casting, crystal growing in the crucible or for refilling other casting or crystal growth crucibles. The material and the porous gas distributor move with respect to each other. One porous gas distributor is cylindrical and is tipped.

Abstract: The present invention provides a method and apparatus for growing a single crystal by the Czochralski method, wherein a single crystal is grown with forced cooling of neighborhood of a crystal growth interface by disposing a cooling cylinder formed of copper or a metal having a heat conductivity larger than that of copper at least in the vicinity of the crystal growth interface so as to surround the single crystal under pulling and circulating a cooling medium in the cooling cylinder. Thus, there are provided a method and apparatus for growing a single crystal, which can exert cooling effect on a growing single crystal to the maximum extent so as to realize higher crystal growth rate, even when a silicon single crystal having a diameter of 300 mm or more is grown.

Abstract: A semiconductor wafer made from silicon which is doped with hydrogen. The hydrogen concentration is less than 5*1016 atcm?3 and greater than 1*1012 atcm?3. A method for producing a semiconductor wafer from silicon includes separating the semiconductor wafer from a silicon single crystal, with the single silicon crystal being pulled from a melt, in the presence of hydrogen, using the Czochralski method. The hydrogen partial pressure during the pulling of the single silicon crystal is less than 3 mbar.

Abstract: In one aspect of the invention, a method for pressurized annealing of lithium niobate or lithium tantalate structures, such as optical modulators and optical wave guides, comprises pressurizing an oxygen atmosphere containing a lithium niobate or lithium tantalate structure above normal atmospheric pressure, heating the structure to a temperature ranging from about 150 degrees Celsius to about 1000 degrees Celsius, maintaining pressure and temperature to effect ion exchange or to relieve stress, and cooling the structure to an ambient temperature at an appropriate ramp down rate.

Abstract: A single crystal silicon wafer comprising a front surface, a back surface, a lateral surface joining the front and back surfaces, a central axis perpendicular to the front and back surfaces, and a segment which is axially symmetric about the central axis extending substantially from the front surface to the back surface in which crystal lattice vacancies are the predominant intrinsic point defect, the segment having a radial width of at least about 25% of the radius and containing agglomerated vacancy defects and a residual concentration of crystal lattice vacancies wherein (i) the agglomerated vacancy defects have a radius of less than about 70 nm and (ii) the residual concentration of crystal lattice vacancy intrinsic point defects is less than the threshold concentration at which uncontrolled oxygen precipitation occurs upon subjecting the wafer to an oxygen precipitation heat treatment.

Abstract: The present invention aims to prevent solidification of a melt in a feeding pipe without providing heating means such as heater or heat keeping means such as heat insulating material on outer periphery of the feeding pipe when the melt is supplied from an auxiliary crucible into a main crucible via the feeding pipe by overflow. At the center of the auxiliary crucible 1 made of quartz, a pipe 1a for feeding the melt from the auxiliary crucible 1 to the main crucible 11 by overflow is formed. When the raw material in the auxiliary crucible is melted, it is designed in such manner that the raw material is not continuously supplied to the auxiliary crucible but it is supplied in such quantity that the melt overflows intermittently into an opening on the upper end of the pipe 1a from the auxiliary crucible 1 into the main crucible 11.

Abstract: In a monocrystal producing device using a pulling-down method, a raw material melt 5m is continuously supplied into a crucible 2 to grow a crystal 18 by supplying a powdery raw material 5p onto a premelt plate 3 inside an electric furnace 10 with a powdery raw material supplying device 20 and melting the powdery raw material 5p on the premelt plate 3 to generate the raw material melt 5m, and causing this raw material melt 5m to drop out inside the crucible 2. A dry air is introduced into the powdery raw material 5p inside the powdery raw material tank 6 to prevent moisture of the raw material powder 5p. A transferring tube 9 for transferring the raw material 5m is cooled to prevent the filling in the transferring tube 9 based on melting of the powdery raw material 5p. This makes it possible to produce a monocrystal having a stable chemical composition, a large diameter, and a long size at a low price.

Abstract: The present invention relates to a method for manufacturing a crystal with at least two segments, wherein adjacent segments differ by at least one characteristic. The different segments can, for example, be of different materials, or have a different doping agent. The method makes possible the manufacturing of segmented crystals with high crystal quality, and as planar joining surfaces between the individual segments as possible. This is achieved in that the segmented crystal is grown directly from the molten mass.

Abstract: A system for growing high-quality, low-carbon-concentration single crystals which have an excellent gas-flow guiding function near the melt, containing 1) an inverted conical, flow-guide cover placed above and coaxially with a double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the single crystal to be grown and the inner surface of the sidewall of the inner crucible; 2) a short passage comprising a hole passing through the sidewall of the inner crucible at a position higher than the level of the melt; and 3) a flow guide cylinder placed above and coaxially with the double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the sidewall of the inner crucible and the inner surface of the sidewall of the outer crucible, all arranged in a furnace.

Abstract: Device for pulling a silicon single crystal 1 includes an element 5 which annularly surrounds the single crystal growing at a crystallization boundary; and the element has a face 6 directed at the single crystal. The element surrounds the single crystal substantially level with the crystallization boundary 2 and has the property of reflecting heat radiation radiated by the single crystal and the similar melt or of generating and radiating heat radiation back to the lower part of the crystal close to the crystallization boundary. There is also a method for pulling a silicon single crystal, in which the single crystal is thermally affected using the element surrounding it.

Abstract: Reactive gas is released through a crystal source material or melt to react with impurities and carry the impurities away as gaseous products or as precipitates or in light or heavy form. The gaseous products are removed by vacuum and the heavy products fall to the bottom of the melt. Light products rise to the top of the melt. After purifying, dopants are added to the melt. The melt moves away from the heater and the crystal is formed. Subsequent heating zones re-melt and refine the crystal, and a dopant is added in a final heating zone. The crystal is divided, and divided portions of the crystal are re-heated for heat treating and annealing.

Abstract: An electrode is disposed at the lower end of a radiation screen. The electrode is made of single-crystal silicon. A circuit including a power source is established by contacting the electrode and the seed crystal to a silicon melt.

Abstract: An apparatus and method for growing large diameter silicon crystals using the Czochralski (Cz) method, wherein the neck section of the crystal is significantly strengthened to eliminate the risk of breakage in the neck section, by providing a heat shield assembly which is located adjacent to the neck section and ascends in conjunction therewith to force the cooling gas directly onto the neck section of the silicon ingot.

Abstract: A system for growing high-quality, low-carbon-concentration single crystals which have an excellent gas-flow guiding function near the melt, containing 1) an inverted conical, flow-guide cover placed above and coaxially with a double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the single crystal to be grown and the inner surface of the sidewall of the inner crucible; 2) a short passage comprising a hole passing through the sidewall of the inner crucible at a position higher than the level of the melt; and 3) a flow guide cylinder placed above and coaxially with the double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the sidewall of the inner crucible and the inner surface of the sidewall of the outer crucible, all arranged in a furnace.