Abstract: A single crystal pulling apparatus which eliminates trouble caused by an isolation valve heated to a high temperature uses a heat insulation plate provided below the isolation valve. The heat insulation plate is operated synchronously with the opening or closing of the isolation valve. The heat insulation plate prevents hot gases from coming from the lower chamber from coming into direct contact with the isolation valve. The prevention of overheating of the isolation valve provides for smooth operation and growth of a good quality single crystal.

Abstract: According to the present invention, in the growth of an oxide single crystal or a compound semiconductor single crystal such as GaAs single crystal by the CZ method or LEC method, the tendency of concave solid-liquid interface shape at the periphery of the growing crystal can be suppressed to prevent polycrystallization without localized heating of the solid-liquid interface, while controlling the diameter of the growing crystal even when using a crucible with a larger diameter, thus improving the yield of crystal on a commercial scale. In the invention, the end of a cylindrical body having an inner diameter of larger than the predetermined diameter of straight part of the growing crystal is immersed in the raw material melt or liquid encapsulant and the crystal is pulled while preventing the shape of the solid-liquid interface from becoming concave by controlling the rotation rate of at least one of a crucible holding the raw material melt, the growing crystal and cylindrical body.

Abstract: A device for producing single crystals has been presented which enables the pulling up and growing of single crystals. Without loss of accurate control of the oxygen concentration in the crystal, and with excellent dielectric strength of subsequently produced gate oxide films. A heat resistant and heat insulating component (7) of cylindrical or cylinder-like form surrounding the pulling up zone of the single crystal is suspended from the ceiling (6a) or the upper part of the wall of the metallic vessel (6) with a gap (h.sub.1) from the ceiling to divide the inert gas (30) supplied from above into inert gas flows (33 and 32) outside and inside this component.

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: A crystal pulling apparatus for producing a crystal boule (17) from a material melted in a crucible (4) has, in a tank (1), a heater (5) surrounding the crucible (4). The tank (1) has in the area of the crucible (4) an annular chamber (8) defined on the heater (5) side by an inner protective wall (6) and connected to the shielding gas outlet (14, 15), and on the outside by an outer protective wall (7) behind which the thermal insulation (10) of the tank (1) is located.

Abstract: Proposed is an improvement in the method and single crystal growing chamber for the preparation of a single crystal rod of silicon by the Czochralski method, according to which the distance between the surface of the melt of silicon contained in a crucible and the lower surface of the top wall of the crystal growing chamber is equal to or larger than the diameter of the crucible and the heat-insulating cylinder surrounding the crucible containing the melt of silicon and the heater has such a height as to reach the lower surface of the top wall of the chamber so as to keep the single crystal rod under growing is kept at a temperature not lower than 700.degree. C. until reaching the lower surface of the top wall of the chamber thereby decreasing the density of the crystal defects of BMD type in the seed end of the single crystal rod as grown so that the uniformity in the distribution of BMD density is increased throughout the single crystal rod.

Abstract: A rotating head (11) for crystal pulling systems (1) according to Czochralski has a reference platform (16) which is able to rotate around a vertical rotation axis (A--A) with a vertical feed-through opening (25) for a pulling cable (13) that can be wound up and a drive assembly (23) for driving a horizontal shaft (22). A winding drum (15) with a helical winding groove (29) for the pulling cable is located on this shaft in a fixed manner so it cannot rotate, but can be moved axially. In order to avoid abrasion and contamination and to accurately guide the cable (13), a helical guiding element (30) with the same pitch as the winding groove is located on the horizontal shaft (22) at a location remote from the vertical rotation axis (A--A). This guiding element is able to rotate with the horizontal shaft.

Abstract: A Czochralski method for producing monocrystals wherein a single crystal silicon rod is pulled from a silicon melt contained in a crucible within a chamber. After pulling the single crystal silicon rod from a silicon melt in a chamber, the chamber is cooled by flowing a gas having a thermal conductivity of at least about 55.times.10.sup.-5 g.cal./(sec..multidot.cm.sup.2)(.degree.C./cm) at 800.degree. K into the chamber. The preferred cooling gas is a helium-containing gas.

Abstract: Proposed is a novel vessel such as crucibles made from PBN (pyrolytic boron nitride), which is highly resistant against exfoliation of the surface layer and suitable for use, for example, as a container of the melt in the Czochralski single crystal growing of III-V Group compound semiconductor single crystals with an improvement in the serviceable life. The PBN-made vessel of the invention is characterized by specific values of several parameters including density, which should be in the range from 1.90 to 2.05 g/cm.sup.3, intensity ratio of the X-ray diffraction peaks representing the degree of orientation, heat conductivity coefficient and the like. The above mentioned advantageous serviceable life of the vessel can be obtained only when these parameter values are satisfied.

Abstract: Arranged is a covering plate which closes and opens an entrance of a valve container between a lower chamber and an upper chamber, the lower chamber containing a crucible and the upper chamber containing a wire to pull a single crystal. The covering plate is contained in a circle-shaped space portion within a wall by closing and opening means. The covering plate closes the entrance so that an isolation valve is protected. Since at the time of opening the entrance the covering plate is contained within the wall without contacting with the wall, the fall of dusts produced by peeling off of a film deposited on the wall can be prevented. Furthermore, the covering plate is contained in a circle-shaped space portion without exposing the front and back surfaces thereof to the air.

Abstract: An improvement is proposed in the single crystal growing process of semiconductor silicon in the Czochralski process to obtain a silicon single crystal having a greatly decreased number of crystal defects without affecting the productivity. The improvement can be accomplished by an adequate arrangement of the cooling zone of the single crystal growing puller to have such a temperature distribution that the time taken by the growing single crystal to pass through the temperature range from the melting point of silicon to 1200.degree. C. is from 50 minutes to 200 minutes and the time taken by the growing single crystal to pass through the temperature range from 1200.degree. C. to 1000.degree. C. does not exceed 130 minutes.

Abstract: A method and an apparatus for fabricating single crystals of superconducting ceramics are described. A powdered row oxide mixture is placed and molten in a melting pot. The surface of the molten mixture is approximately at the freezing point of the mixture. From the surface, a single crystal is pulled in accordance with the known pulling crystal technique. The pulled mixture is subjected to a magnetic field normal to the pulling direction. By virtue of the magnetic field, single crystal superconducing oxide ceramics can be obtained without twin crystals.

Abstract: A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.

Abstract: A method for controlling oxygen precipitation (106) in a silicon crystal (12) grown according to the Czochralski silicon crystal growing technique which includes the steps of forming a cylindrical portion (22) of the silicon crystal (12) from a reservoir of molten silicon (24) according to the Czochralski silicon crystal growing technique. The method includes the steps of terminating the Czochralski silicon crystal growing technique by forming a first tapered portion (101) in silicon crystal (12) at a predetermined rate. A second tapered portion (102) includes a cascaded middle portion (108) that connects to the first tapered portion (101) and that concentrates oxygen precipitation (106) within cascaded middle portion (108) and away from the cylindrical portion (22) of silicon crystal (12). At least a third tapered portion (104) is formed for separating silicon crystal (12) from molten silicon (24).

Abstract: A lock valve disposed between a pulling pot and a lock chamber is opened at the start of the pulling process and thereby uncovers a lock entrance for the crystal that is to be pulled, and together with a gasket closes the lock entrance after the end of the pulling process and thereby hermetically separates the pulling pot from the lock chamber. The gasket (9) is protected during the pulling of the crystal by a guard (15, 16) against the thermal radiation of the hot crystal.

Abstract: Apparatus and methods for pulling a semiconductor crystal according to a Czochralski method are disclosed. The apparatus includes a crucible containing a melt, a crystal pulling mechanism which pulls the semiconductor crystal from the melt, a motor coupled to the crucible, and a control circuit for energizing the motor to rotate the crucible at a variable speed. The control circuit may energize the motor to rotate the crucible at a continuously varying acceleration and continuously varying rotational speed while the crystal pulling mechanism is pulling at least a portion of the semiconductor crystal from the melt in the crucible. The control circuit may also energize the motor to rotate the crucible at a rotational speed which monotonically increases and decreases.

Abstract: A source (1) is equipped with a conveying device (4) for discharging the particles (2, 2a) at adjustable rates per unit time. A crystal (16), formed from doped particles, is withdrawn from the melting crucible (13) at a predetermined rate per unit time. So that the control process can be conducted smoothly over prolonged periods of time with precise doping, the particles (2, 2a) are fed single file to the melting crucible (13) and counted by at least one sensor (21, 22). The sequence of count pulses is sent to a counter (25) and compared there with a corresponding sequence of reference input pulses. The comparison signal formed from the count pulses and the reference input pulses is used, in accordance with its sign, as a control signal for adjusting the amount of particles being discharged per unit time from source (1) to correspond to the reference value.

Abstract: A method of laterally adjusting the position of a pull wire of a crystal pulling machine to dampen pendular motion of the pull wire during production of a monocrystal comprises: placing a close-fitting guide around the pull wire; rotating the pulling chamber about the axis Z.sub.1 to rotate both the pull wire and the monocrystal supported by the pull wire; sensing the lateral position of a portion of the pull wire; adjusting the lateral position of the guide in response to the sensed position of the pull wire to dampen pendular motion of the pull wire during production of a monocrystal.

Abstract: This invention relates to the apparatus and the process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The apparatus is provided with a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a cylindrical shaped heat resistant and heat insulating component below the protective gas inlet pipe noted above.

Abstract: An apparatus for producing a single crystal comprising a heater which is arranged on the outer periphery of a crucible and movable along the axis of growth of a single crystal. The heater is moved along the direction of growth of the single crystal in accordance with the surface position of the molten liquid layer in the crucible. The apparatus for producing a single crystal further comprising means for adjusting the speed at which the seed crystal is pulled. For example, the pulling speed of the seed crystal is adjusted in accordance with the position of the heater.

Abstract: A hopper is sized and shaped for reception in a crystal pulling apparatus for use in charging semiconductor source material to a crucible of the crystal pulling apparatus. The crystal pulling apparatus includes a pulling chamber, a growth chamber, an isolation valve operable to seal the growth chamber from the pulling chamber, and a crucible in the growth chamber. The hopper includes a bin constructed for containing a quantity of semiconductor source material. The bin has an opening in its bottom for delivery of the semiconductor source material from the bin to the crucible. A stopper constructed for closing the opening to prohibit passage of semiconductor source material from the bin is moved by a stopper actuating mechanism between a closed position and an open position. A connector attached to the hopper is constructed for temporarily mounting the hopper in the crystal pulling apparatus.

Abstract: A method of growing semiconductor crystals including inserting a single crystal seed (14) of a semiconductor material into a melt (12) and pulling the seed (14) at a first rate to gradually grow an elongated, single crystal first neck (15), altering the pulling rate to a second rate, slower than the first rate, to grow a shoulder (17) on the first neck (15) with a diameter greater than the first neck (15), continuing to pull at the second rate to form a second neck (18) with a diameter equal to the diameter of the shoulder (17), and altering the pulling rate to a third rate, slower than the second rate, to grow a single crystal elongated body (20) of the semiconductor material.

Abstract: The density of a melt precisely represents the stability of the melt, so that the initiation of pulling-up operation can be determined on the basis of the changing rate of the density. The pulling-up operation may be started when the density becomes constant, or when the changing rate of the density with respect to the temperature becomes smaller. Since the melt or clusters do not include different minute structures, an obtained single crystal is of high quality free from minute faults or dislocations.

Abstract: A method of producing a silicon single crystal, in which a cylindrical partition is immersed in a molten pure silicon liquid or molten silicon liquid containing a Sb dopant within a crucible and the molten liquid inside the partition is pulled up from the crucible to produce the silicon single crystal, wherein an interval between a lower end of the partition and a crucible bottom is changed to control an oxygen concentration in the pulling-up silicon single crystal. The interval is reduced in the case where the oxygen concentration in the pulling-up silicon single crystal is to be increased while the interval is increased in the case where the oxygen concentration is to be reduced.

Abstract: A melt is crystallized by introducing the melt into a gap formed between two belts. The gap-forming flights of the belts travel in opposite directions. An upper one of the flights is cooled so that an upper surface of the melt crystallizes thereon and is removed from the gap on the upper belt. The lower belt removes the residual melt from the gap and that residual melt is recycled to the gap.

Abstract: A CZ crystal growing furnace which has a radiative heat shield that can be raised and lowered above a crucible. The heat shield assembly includes an upper heat shield that is mounted to a furnace cover directly above the crucible. Coupled to the upper shield is a lower heat shield which can move between a first raised position and a second lower position. Attached to the seed holder of the furnace is a bar which maintains the lower heat shield in the first raised position, so that the crucible can be filled with raw silicon. After the silicon is melted, the heat shield is lowered to the second position and the bar is lifted and removed from the furnace. The lower heat shield has an outer ring which cooperates with an inner ring of the upper heat shield to suspend the lower shield in the second position. The heat shield also has a tapered wall which defines an opening that allows an ingot to be pulled from the molten silicon.

Abstract: An apparatus for pulling up a single crystal according to Czochralski method is provided with a cylindrical first screen and a second screen. The first screen is arranged in the periphery of the zone of pulling up the single crystal, said screen being constituted by a heat absorbing body at the side facing a quartz crucible and by a heat insulator at the other side and being provided with respective outward and inward annular rims at the upper and lower ends thereof, the corner of said screen facing the crucible being formed in a curved or polygonal structure, and said annular rim at the lower end being positioned in the vicinity of filling the melt in the crucible. The second screen forming a parabolic shape in the section opening at its center while enclosing the crystal pulling-up zone and being provided at its upper end with an outward annular rim.

Abstract: A process and an apparatus for carrying out the process provides for the accurate and simple control of the melt level when pulling single crystals according to the Czochralski process. The process comprises disposing a mechanical reference mark above the melt in such a way that it causes a reflection from the melt surface. An image of the metal surface is then recorded, and with the aid of the recorded image the distance of the mechanical reference mark from the melt surface is determined. An actual signal proportional to this distance is then generated and is compared with a set point signal, and the melt level is changed as a function of any difference observed.

Abstract: An apparatus for producing a single crystal comprising a heater which is arranged on the outer periphery of a crucible and movable along the axis of growth of a single crystal. The heater is moved along the direction of growth of the single crystal in accordance with the surface position of the molten liquid layer in the crucible. The apparatus for producing a single crystal further comprising means for adjusting the speed at which the seed crystal is pulled. For example, the pulling speed of the seed crystal is adjusted in accordance with the position of the heater.

Abstract: A device for pulling a silicon single crystal is constructed so as to preclude deposition of a SiO-derived substance on graphite parts inside the device and prevent the graphite parts from deterioration, elongate the duration of continuous use of the device in a great measure, and simplify the disassembly and reassembly of the device.This device pulls a silicon single crystal in an atmosphere of inert gas by the Czochralski method, which device is chracterized by comprising a crucible 1 for accommodating a molten silicon mass 2, a heater 3 disposed round the periphery of the crucible 1, an outer member 14 forming a pulling chamber 6 for accomodating the crucible 1, an inert gas inlet part 15 disposed in the upper part of the pulling chamber 6, and an inert gas outlet part 16 separated from the inert gas inlet part 15 in the same upper part of the pulling chamber 6.

Abstract: An apparatus for use in solidification of a doped electrically conducting material and for use in monitoring said solidification is provided. The apparatus includes a first forming means for forming a liquid of undoped material in thermodynamic equilibrium with a solid of the undoped material, and a second forming means for forming a liquid of doped material in thermodynamic equilibrium with a solid of the doped material. Solidification of the conducting material occurs at a solidification interface between the doped liquid and the doped solid in the second forming means. In one preferred embodiment, the apparatus comprises a conductive bridge for short-circuiting the liquids.

Abstract: Apparatus and method are provided for growing improved quality long and large single crystals in a liquid encapsulated Czochralski (LEC) process, in which a separate cooling circuit is provided for the upper portion of a vessel which cools that portion independently of any cooling means for the lower portion of the vessel, and in which the gas flow pattern can desirably be controlled such that the gas flow is predominantly downward adjacent the vessel wall, and predominantly upward near the center of the vessel, where the crystal is being pulled from the melt.

Abstract: A method of growing a single semiconductor crystal with a flat top. In order to grow a single flat top crystal, the InP crystal is pulled up after the temperature drop of the melt has almost stopped, at a point in time when a meniscus at the interface of solid-liquid can be seen over the whole circumference of the surface of the melt. This prevents a facet from appearing at the shoulder portion of the crystal, thus reducing the generation of twin crystals and drastically improves retension of single crystal formation.

Abstract: A single crystal pulling apparatus based on Czochralski technique having a conduit for continuously supplying granular polycrystal material to the crucible and a vertical purge tube suspended centrally into the heating chamber, wherein the purge tube is vertically shiftable; a heat shield ring is connected to the lower end of the purge tube, and a cylindrical quartz partition ring made of a quartz glass containing no bubbles is held vertically by the heat shield ring in a manner such that the lower end of the quartz partition ring comes substantially lower than the lower end of the purge tube so that, by being dipped in the polycrystal melt, the partition ring isolates the interior surface of the melt from the exterior surface of the melt, over which latter the granular polycrystal material is poured.

Abstract: An apparatus and a method are presented for preparing a single crystal ingot of a compound semiconductor material which contains a high vapor pressure component. The apparatus includes: a furnace housing 78 housing a cylindrical hermetic vessel 20 having a ceiling plate section 22A and a bottom plate section 42. External heaters 36, 38 and 40 surrounding the hermetic vessel 20, and a vapor pressure control section which communicates hermetically with the vessel 20.

Abstract: A method for growing multiple high-purity single crystals from a replenished melt by maintaining the purity of molten source material in the melt held in a crucible in a furnace of the type used for growing high-purity single crystals. The method includes the steps of growing at least one crystal from the source material in the crucible, extracting a portion of a volume of the melt remaining in the crucible, adding high-purity source material to the melt, and growing at least one more single crystal. Extractor apparatus used in the method includes an insulated receptacle having an inlet tube for conducting molten source material into the receptacle. A vacuum attached to the receptacle is used to draw the source material into the receptacle.

Abstract: A support crucible includes a central axis, outer radii including longest outer radii defining planes with the central axis, a side wall region having a circumferential direction and a bottom. At least two neighboring segments are separated by joints extending substantially vertically in the side wall region to the bottom and penetrating the bottom. The joints define opposed surfaces of the neighboring segments which always overlap each other in the circumferential direction of the side wall region in an operating state. Each of the surfaces is intersected by a respective one of the planes, at least in the side wall region. According to another embodiment, the joints defining opposed surfaces of the neighboring segments have complementary shapes, the surfaces are formed by cuts beginning at a jacket surface of the side wall region and extending parallel to the central axis and at an angle to the planes, and the cuts extend in a curve to the central axis.

Abstract: Growth of monocrystalline rods from a bulk melt is carried out by a modified Czochralski process using a float which floats on the bulk melt held in a crucible. Melt flows through a passageway in the float to a crystal growth zone at a rate which prevents diffusion of dopant from the growth zone to the bulk melt. The shape of the crystal may be determined by a shaper wall in the float which defines the growth zone, in which case the crystal body is pulled from the float as it grows without rotating the crystal. The temperature of the float near the shaper wall may be monitored and controlled to control the crystallization process.

Abstract: The present invention provides control of single crystal growth after the recovery from power failure when controlling crystal growth in an automatic mode. A source voltage is supplied to a controller 70 through a no-break power supply 62. At the time of recovery from power failure, the controller continues the automatic operation mode with the same control output as that stored when power failure is detected (84, 85) if the power failure time t is t .ltoreq.t.sub.1 (for example, 1 second), switches the control mode to the manual control mode with the same control output as that stored when the power failure is detected (86, 87) if t.sub.1 <t.ltoreq.t.sub.2 (for example, 5 seconds), stops the crystal growth operation and switches the control mode to the manual control mode (88, 89) if t.sub.2 <t.ltoreq.t.sub.3 (for example, 600 seconds), and separates the grown crystal from a melt 22 by upwardly moving the crystal and upwardly moves a crucible 16 (90) if t>t.sub.3.

Abstract: A Czochralski crystal pulling apparatus for carrying out the Czochralski crystal pulling process is provided with a reflecting plate for reflecting radiation heat radiated from the surface of a molten material contained in a crucible toward a contact region of the surface of the molten material contiguous with the wall of the crucible to heat the molten material in the contact region so that the temperature of the molten material in the contact region may be prevented to reach the solidifying point. The reflecting plate is suspended by wires from cross beams so that the radiation heat transfer from the surface of a crystal toward a surrounding radiation heat transfer surface of a furnace may not be intercepted. The surface of the molten material is maintained on a level above the upper end of a high temperature region of a heater so that the surface of the molten material may be kept in comparatively low temperature to promote the crystal growth rate.

Abstract: A single crystal pulling apparatus of Czochralski technique type including (i) a cylindrical partition adapted to divide the surface portion of the melt into an inner part and an outer part, the former being where the single crystal is grown and the latter being where granular polycrystal material is supplied, (ii) a flat ring having heat reflecting and insulating property held horizontally above the melt, and (iii) a vertically shiftable purge tube suspended centrally into the heating chamber adapted to enter into the inner hole of the flat ring.

Abstract: A prefusing crucible in a closed prefusing tank is provided above a melting crucible in a closed vacuum container. Prefusing the charge material prevents thermal shock to the melt in the crucible from which monocrystals are drawn. A cover provided over the overflow from the prefusing crucible acts as a dust trap.