Abstract: A scintillator single crystal of a specific cerium-doped silicate compound that contains 0.00005 to 0.1 wt % of one or more types of element selected from the group consisting of elements belonging to group 2 of the periodic table based on the total weight of the single crystal.
Abstract: Disclosed is a method of fabrication of high quality silicon single crystal at high growth rate. The method grows silicon single crystal from silicon melt by Czochralski method, wherein the silicon single crystal is grown according to conditions that the silicon melt has an axial temperature gradient determined according to an equation, {(?Tmax??Tmin)/?Tmin}×100?10, wherein ?Tmax is a maximum axial temperature gradient of the silicon melt and ?Tmin is a minimum axial temperature gradient of the silicon melt, when the axial temperature gradient is measured along an axis parallel to a radial direction of the silicon single crystal.
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 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: A method of production of a silicon carbide single crystal enabling fast, stable, and continuous growth of a high quality silicon carbide single crystal and enabling both an increase in size of the bulk single crystal and an improvement of quality of a thin film single crystal, comprising stacking, in order from the bottom, a silicon carbide source material rod, a solvent, a seed crystal, and a support rod supporting the seed crystal at its bottom end so as to form a columnar workpiece, heating a bottom end of the source material rod as a bottom end of the columnar workpiece, and cooling a top end of the support rod as the top end of the columnar workpiece so as to form a temperature gradient inside the columnar workpiece so that the top end face becomes lower in temperature than the bottom end face of the solvent; and causing a silicon carbide single crystal to grow continuously downwardly starting from the seed crystal, wherein said method further comprises using an inside cylindrical susceptor tightly surr
Abstract: In silicon single crystal growth by the Czochralski method using a quartz crucible, a silicon single crystals with a uniform distribution of oxygen concentration can be produced in high yield without being affected by changes of crystal diameter and initial amount of melt feedstock. The oxygen concentration is adjusted by estimating oxygen concentration during growth on the basis of a relationship among three parameters: crucible rotation rate (?), crucible temperature (T), and the ratio (?) of contact area of molten silicon with the inner wall of the crucible and with atmospheric gas, and by associating the temperature (T) with the ratio (?) by the function 1/?×Exp(?E/T) where E is the dissolution energy (E) of quartz into molten silicon to control at least one of the rotation rate (?) and temperature (T) to conform the estimated oxygen concentration to a target concentration.
Abstract: A method for producing a single crystal by Czochralski method with pulling a seed crystal from a raw material melt, wherein in which a range of a pulling rate of pulling a single crystal, a temperature gradient at a solid-liquid interface and a highest temperature at an interface between a crucible and a raw material melt are defined. The single crystal is pulled with controlling the pulling rate and/or the temperature gradient at a solid-liquid interface within the determined range. The method produces a single crystal in which a desired defect region and/or a desired defect-free region can be determined more precisely and a single crystal with desired quality can be more surely pulled.
Abstract: An active layer side silicon wafer is heat-treated in an oxidizing atmosphere to thereby form a buried oxide film therein. The active layer side silicon wafer is then bonded to a supporting side wafer with said buried oxide film interposed therebetween thus to fabricate an SOI wafer. Said oxidizing heat treatment is carried out under a condition satisfying the following formula: [Oi]?2.123×1021exp(?1.035/k(T+273)), where, T is a temperature of the heat treatment, and [Oi] (atmos/cm3) is an interstitial oxygen concentration.
Abstract: The invention relates to a technique for producing a high quality Si single crystal ingot with a high productivity by the Czochralski method. The technique of the invention can control the magnetic field strength of an oxygen dissolution region different from that of a solid-liquid interface region in order to control the oxygen concentration at a desired value.
Abstract: A vitreous silica crucible for pulling single-crystal silicon, comprising a surface glass layer having a thickness of 100 ?m from an inner surface of the crucible, and a glass layer provided below the surface glass layer in a thickness direction of the crucible and extending to a depth of 1 mm from the inner surface of the crucible. The concentration of OH groups in the surface glass layer is 90 ppm or less, and the concentration of OH groups in the glass layer is equal to or more than 90 ppm and equal to or less than 200 ppm. The bubble content in the glass layer is 0.1% or less.
Abstract: It is an object of the present invention to provide a self-coated single crystal that without any special step conducted after crystal growth, has its circumference coated with a layer of different properties. A self-coated single crystal according to the present invention is characterized in that in operations comprising melting crystal materials for a core and a clad in a single crucible and carrying out growth of a single crystal through a pulling up method or a pulling down method, a grown single crystal in an as-growth condition has its circumference self-coated with a clad whose refractive index is lower than that of the core.
Abstract: A vitreous silica crucible for pulling single-crystal silicon, which is formed of vitreous silica and has a bottomed cylindrical shape, wherein, in a liquid-level movement range in the inner surface of the crucible, ranging from a position corresponding to the liquid surface level of a silicon melt at the time of stating the pulling of single-crystal silicon to a position corresponding to the liquid surface level of a silicon melt at the time of finishing the pulling of single-crystal silicon, the concentration of an OH group included in the vitreous silica is higher in an erosion thickness portion of the inner surface of the crucible than that in the range lower than the liquid surface level which is positioned below the liquid-level movement range
Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
Abstract: In a process for manufacturing a LT substrate from a LT crystal, after growing the crystal, a LT substrate in ingot form is imbedded in carbon power, or is place in a carbon vessel, and heat treated is conducted at a maintained temperature of between 650° C. and 1650° C. for at least 4 hours, whereby in a lithium tantalate (LT) substrate, sparks are prevented from being generated by the charge up of an electric charge on the substrate surface, and thereby destruction of a comb pattern formed on the substrate surface and breaks or the like in the LT substrate are prevented.
Abstract: Disclosed are a czochralski apparatus for growing crystals and a purification method of waste salts using the same. More particularly, the present invention provides a czochralski apparatus for growing crystals comprising screw thread for fixing salt crystals mounted on a pulling bar of the apparatus in order to prevent desorption of crystals caused by load thereof during a crystal growing process without requiring alternative seed crystals and, in addition, a method for purification of waste salts, which can isolate impurities from molten waste salts using a czochralski crystal growing process without alternative adsorption medium, does not generate secondary wastes and may continuously purify the waste salts.
Type:
Application
Filed:
April 3, 2008
Publication date:
June 4, 2009
Inventors:
Jong-Hyeon Lee, Han-Soo Lee, In-Tae Kim, Yoon-Sang Lee, Eung-Ho Kim
Abstract: An oxide film 13 on the surface of the substrate 11 and an inner wall oxide film 112 in a COP 111 exposed to the surface of the substrate 11 are removed by cleaning the surface of the substrate 11 with a hydrofluoric acid solution. The substrate 11 is then cleaned with ozone water, thereby forming an oxide film 13 on the surface of the substrate 11. Thereafter the substrate 11 is subjected to a heat treatment for removing the oxide film 13 on the surface of the substrate 11. Consequently, the COP 111 on the surface of the substrate 11 is planarized to be eliminated from the substrate surface. Thereafter an epitaxial layer 12 is formed on the surface of the substrate 11.
Abstract: A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon wafer by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) [ Oi ] < [ Oi ] eq ? ( T ) ? exp ? 2 ? ? SiO ? ? 2 ? ? rkT is satisfied, where [Oi] is an oxygen concentration in the silicon wafer, [Oi]eq(T) is a limit solubility of oxygen in silicon at a temperature T, ?SiO2 is the surface energy of silicon dioxide, ? is a volume of a precipitated oxygen atom, r is a mean COP and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least part of the time being exposed to an oxygen-con
Type:
Grant
Filed:
June 29, 2006
Date of Patent:
May 26, 2009
Assignee:
Siltronic AG
Inventors:
Christoph Seuring, Robert Hoelzl, Reinhold Wahlich, Wilfried Von Ammon
Abstract: In order to provide a semiconductor single crystal manufacturing device and a manufacturing method using a CZ method wherein the resistivity and oxygen concentration of a silicon single crystal can be controlled and wherein a single crystal yield can be improved, in the present invention, there is provided a wall 10 which defines a chamber inner wall 1c of a chamber 1, a crucible 2 and a heater 3. The wall 10 is formed by three members, namely, a single crystal side flow-straightening member 11, a melt surface side flow-straightening member 12 and a heater side flow-straightening member 13, which are connected to form a purge gas directing path 100. When the semiconductor single crystal is pulled, a flow speed of a purge gas that passes through the vicinity of the surface of the melt in a quartz crucible 3 is controlled from 0.2 to 0.35 m/min by purge gas introduction means.
Abstract: The present invention provides a single crystal heat treatment method, having a step of heating a single crystal of a cerium-doped silicate compound represented by any of general formulas (1) to (4) below in an oxygen-containing atmosphere Y2?(x+y)LnxCeySiO5??(1) (wherein Ln represents at least one elemental species selected from a group consisting of elements belonging to the rare earth elements, x represents a numerical value from 0 to 2, and y represents a numerical value greater than 0 but less than or equal to 0.2) Gd2?(z+w)LnzCewSiO5??(2) (wherein Ln represents at least one elemental species selected from a group consisting of elements belonging to the rare earth elements, z represents a numerical value greater than 0 but less than or equal to 2, and w represents a numerical value greater than 0 but less than or equal to 0.
Abstract: A method for controlling the temperature gradient on the side surface of a silicon single crystal, the height of a solid-liquid interface, and the oxygen concentration in the longitudinal direction of the silicon single crystal is provided in order to manufacture a defect-free silicon single crystal whose oxygen concentration is controlled to a predetermined value rapidly and stably. By disposing a cylindrical cooler around the silicon single crystal, and adjusting the pulling speed of the silicon single crystal, the rotation speed of a crucible that stores molten silicon and the rotation speed of the silicon single crystal, and the output ratio of a multi-heater separated into at least two in the longitudinal direction of the silicon single crystal disposed around the crucible, the temperature gradient on the side surface, the height of the solid-liquid interface, and the oxygen concentration in the longitudinal direction of the silicon single crystal are controlled.
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: A process for producing a single crystal of semiconductor material, in which fractions of a melt, are kept in liquid form by a pulling coil, solidify on a seed crystal to form the growing single crystal, and granules are melted in order to maintain the growth of the single crystal. The melting granules are passed to the melt after a delay. There is also an apparatus which Is suitable for carrying out the process and has a device which delays mixing of the molten granules and of the melt.
Abstract: A vitreous silica member of the present invention is characterized by being formed of vitreous silica exhibiting the easily crystallizable property in the absence of a crystallization accelerator. The vitreous silica having the easily crystallizable property is obtained preferably by heating and melting crystalline quartz at a temperature in the range of 1,710° C. or more to 1,780° C. or less for vitrification, and controlling the fictive temperature of the glass to be in the range of 1,100° C. or more to 1,400° C. or less. The invention also includes a vitreous silica crucible and a method of pulling single-crystal silicon using this vitreous silica crucible.
Abstract: A crystallization system is provided comprising a trial generation station configured to generate crystallization trials in trial zones of a crystallization plate; an imaging station configured to take images of crystallization trials in the crystallization plate; a transport mechanism configured to transport the crystallization plate to the imaging station after generation of the crystallization trials; and a controller including logic for causing the trial generation station to generate the crystallization trials in the crystallization plate, logic for causing the transport mechanism to transport the crystallization plate to the imaging station and logic for causing the imaging station to take images of the crystallization trials.
Abstract: A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.
Abstract: Methods and apparatus for concurrent growth of multiple crystalline ribbons from a single crucible employ meniscus shapers to facilitate continuous growth of discrete and substantially flat crystalline ribbons having controlled width.
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: The invention intends to provide a single crystal material that can be used as a dielectric material for use in electronic devices, which has a high Qf value; and a process for producing the same. According to the invention, a single crystal of a composite oxide is obtained from a composition in which a slight amount of SrTiO3 is added to LaAlO3, and the (1-X)LaAlO3—XSrTiO3 single crystal material having the specific composition has such dielectric characteristics for electronic devices that the dielectric constant is 24 or more and the Qf value is 300,000 GHz or more, is considerably improved in the Qf value as a dielectric material, and can be applied to a high-temperature superconducting filter.
Abstract: A method of pulling up a silicon single crystal is provided in which a variation rate of a neck diameter is controlled to be within a predetermined range, and a dislocation in a neck is eliminated. When pulling up the silicon single crystal, a single crystal with a predetermined crystal diameter is grown by bringing a seed crystal into contact with a material silicon melt, pulling up the seed crystal, growing the neck, and then increasing a diameter. The above-mentioned neck diameter is increased and decreased to grow the neck, during which a neck diameter variation rate is greater than or equal to 0.05 and less than 0.5, assuming that a value obtained in such a manner that a neck diameter difference (A?B) between adjoining inflection points is divided by a neck length L between the above-mentioned inflection points P1 and P2 is the neck diameter variation rate.
Abstract: The method provides a uniform low-stress single crystal in a predetermined crystal orientation. The method of making it includes immersing a single crystal held at a temperature under its melting point in a melt of crystal raw material and drawing it from the melt to grow the crystal. The crystal and/or melt are rotated relative to each other during the crystal growth. A planar phase boundary surface is maintained by detecting at least one characteristic surface temperature in an interior of a crucible containing the melt and controlling temperature fluctuations by increasing or decreasing the rotation speed when they occur. The single crystals obtained by this method have a diameter of at least 50 mm and no visible growth strips in a fishtail pattern when a 2-mm thick sample is observed between crossed polarizers. Optical elements suitable for DUV lithography can be made from these crystals.
Type:
Grant
Filed:
September 11, 2006
Date of Patent:
January 13, 2009
Assignee:
Schott AG
Inventors:
Gunther Wehrhan, Lutz Parthier, Daniel Rytz, Klaus Dupre, Lothar Ackermann
Abstract: A silicon single crystal is grown using the Czochralski method. During the crystal growth, a thermal stress is applied to at least a portion of the silicon single crystal. A gaseous substance containing hydrogen atoms is used as an atmospheric gas for growing the crystal.
Abstract: The Czochralski method is used for producing p?-doped and epitaxially coated semiconductor wafers from silicon, wherein a silicon single crystal is pulled, and during the pulling is doped with boron, hydrogen and nitrogen, and the single crystal thus obtained is processed to form p?-doped semiconductor wafers which are epitaxially coated.
Type:
Grant
Filed:
October 11, 2007
Date of Patent:
December 30, 2008
Assignee:
Siltronic AG
Inventors:
Wilfried von Ammon, Katsuhiko Nakai, Martin Weber, Herbert Schmidt, Atsushi Ikari
Abstract: In a Czochralski (CZ) single crystal puller equipped with a cooler and a thermal insulation member, which are to be disposed in a CZ furnace, smooth recharge and additional charge of material are made possible. Further, elimination of dislocations from a silicon seed crystal by use of the Dash's neck method can be performed smoothly. To these ends, there is provided a CZ single crystal puller, wherein a cooler and a thermal insulation member are immediately moved upward away from a melt surface during recharge or additional charge of material or during elimination of dislocations from a silicon seed crystal by use of the Dash's neck method.
Abstract: A ribbon crystal pulling furnace has a base insulation and a liner insulation removably connected to the base insulation. At least a portion of the liner insulation forms an interior for containing a crucible.
Type:
Application
Filed:
June 13, 2008
Publication date:
December 18, 2008
Applicant:
EVERGREEN SOLAR, INC.
Inventors:
Richard Wallace, David Harvey, Weidong Huang, Scott Reitsma, Christine Richardson
Abstract: Single crystalline ingots can be stably pulled free from dislocation and with a good crystal shape by actuating a crystal driving unit so as to immerse a seed crystal in a silicon melt, and controlling the crystal driving unit and a crucible driving unit under predetermined conditions so as to pull the seed crystal. During pulling, a horizontal magnetic field positioning device applies a magnetic field in the horizontal direction to the inside of the silicon melt, fixing the magnetic field axis at a constant position from the liquid surface of the melt. Positional adjustment of the vertical position of the horizontal magnetic field is performed in advance by a magnetic field position adjusting device, and the magnetic field axis of the applied field is fixed at a constant distance lower than the liquid surface of the melt by more than 50 mm and at the same level or higher than a depth L from the melt surface at the point of tail-in.
Abstract: A crucible for the treatment of molten silicon includes a basic body with a bottom surface and lateral walls defining an inner volume. The basic body comprises at least 65% by weight of silicon carbide, and from 12 to 30% by weight of a constituent selected from silicon oxide or nitride. Moreover, the basic body comprises at least one silicon oxide and/or nitride coating, at least on the surfaces defining the inner volume of the crucible.
Abstract: A crucible has a structure where a layer containing a crystallization accelerating component such as aluminum or the like (a crystallization accelerating layer) is inserted inside a quartz glass layer of a crucible straight body part excepting a crucible bottom part. The crucible does not deform and fall inwardly at the straight body part since a part containing a crystallization accelerating component advances to crystallize so as to increase strength at a high temperature when the crucible is used in pulling up silicon single crystal. Therefore, a single crystallization rate can be increased. Further, since the crystallization accelerating layer is inserted inside the quartz glass layer, the crystallization accelerating component, such as aluminum or barium, does not contact with silicon melt or a carbon susceptor, contamination by eluting these metals does not occurs.
Abstract: A method is provided for operating a crystallization system comprising identifying a screen storage plate from among the plurality of screen storage plates stored in a screen storage station, each screen storage plate having a plurality of wells that contain a screen solution and at least a portion of the screen storage plates having a selection of screen solutions that is different from the selection of screen solutions held in other screen storage plates; having a transport mechanism transport the identified screen storage plate to a screen replicator; transporting a plurality of crystallization plates to the screen replicators; and having the screen replicator transfer the screen solutions from the identified screen storage plate to the plurality of crystallization plates.
Abstract: In the production of GaN through the flux method, deposition of miscellaneous crystals on the nitrogen-face of a GaN self-standing substrate and waste of raw materials are prevented. Four arrangements of crucibles and a GaN self-standing substrate are exemplified. In FIG. 1A, a nitrogen-face of a self-standing substrate comes into close contact with a sloped flat inner wall of a crucible. In FIG. 1B, a nitrogen-face of a self-standing substrate comes into close contact with a horizontally facing flat inner wall of a crucible, and the substrate is fixed by means of a jig. In FIG. 1C, a jig is provided on a flat bottom of a crucible, and two GaN self-standing substrates are fixed by means of the jig so that the nitrogen-faces of the substrates come into close contact with each other. In FIG. 1D, a jig is provided on a flat bottom of a crucible, and a GaN self-standing substrate is fixed on the jig so that the nitrogen-face of the substrate is covered with the jig.
Abstract: A method for manufacturing a group III nitride crystal on a seed crystal in a holding vessel holding therein a melt containing a group III metal, an alkali metal and nitrogen. The manufacturing method comprises the steps of causing the seed crystal to make a contact with the melt, setting an environment of the seed crystal to a first state offset from a crystal growth condition while in a state in which said seed crystal is in contact with the melt, increasing a nitrogen concentration in the melt, and setting the environment of the seed crystal to a second state suitable for crystal growth when the nitrogen concentration of the melt has reached a concentration suitable for growing the seed crystal.
Abstract: This method for producing silicon single crystals includes: growing a silicon single crystal by the Czochralski method while cooling at least part of the silicon single crystal under growth with a cooling member which circumferentially surrounds the silicon single crystal and has an inner contour that is coaxial with a pull axis, wherein an ambient gas in which the silicon single crystal is grown includes a hydrogen-atom-containing substance in gaseous form. This silicon single crystal is produced by the above method.
Abstract: A crystallization system is provided comprising a screen generation station; a screen storage station; including a housing configured to store a plurality of screen storage plates and mechanics for retrieving a selected screen storage plate from among the plurality of screen storage plates for transport to another station a transport mechanism configured to transport a screen storage plate containing the screen solutions generated at the screen generation station to the screen storage station; and a controller.
Abstract: A silicon single crystal is manufactured by growing said crystal composed of a defect-free area free from the Grown-in defects by the CZ process, adding a gas of a hydrogen atom-containing substance to an atmosphere gas within a growing apparatus, and doping nitrogen and/or carbon in the crystal. Therefore, a wafer the whole surface of which is composed of the defect-free area free from the Grown-in defects and which can sufficiently and uniformly form BMD can be easily sliced. Such a wafer can be extensively used, since it can significantly reduce generation of characteristic defectives of integrated circuits to be formed thereon and contribute for improving the production yield as a substrate responding to the demand for further miniaturization and higher density of the circuits.
Abstract: A trial generation station is provided comprising: a deck configured to receive a crystallization plate from a transport mechanism, the crystallization plate including a plurality of trial zones where crystallization trials are generated; and a head configured to be moved relative to the stage, the head including a plurality of primary fluid dispensers, each fluid dispenser being configured to transfer a portion of a mother liquor from the well region of a trial zone to a sample region associated with the trial zone, and one or more secondary fluid dispensers configured to dispense a molecule solution into the sample regions of the wells, the molecule solution including the molecule to be crystallized by the system and at least one of the secondary fluid dispenser being laterally immobilized relative to one or more of the fluid dispensers.
Abstract: A process for producing 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.
Type:
Grant
Filed:
March 24, 2005
Date of Patent:
October 7, 2008
Assignee:
MEMC Electronic Materials, Inc.
Inventors:
Robert J. Falster, Vladimir V. Voronkov, Paolo Mutti, Francesco Bonoli
Abstract: The axial temperature gradient G at the vicinity of the solid-liquid interface 24 in an ingot is calculated in consideration of the heating value of a heater 18, the dimensions and physical property values of furnace inside components and the convection of the melt 12 before pulling up the single crystal ingot 15 by a puller 10 by use of a numerical simulation of synthetic heater transfers and a numerical simulation of melt convection. Then, the pulling velocity V of the single crystal ingot is determined from an value experienced of the ratio C=V/G of the pulling velocity V and the axial temperature gradient G of the single crystal ingot at which the single crystal ingot becomes defect-free, obtained when the single crystal ingot was pulled up by a same type puller as the puller in the past, and the axial temperature gradient G calculated by use of the simulations.
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 present invention relates to silicon nitride mould parts, particularly crucibles for use in connection with directional solidification and pulling of silicon single crystals. The mould parts consist of Si3N4 having a total open porosity between 40 and 60% by volume and where more than 50% of the pores in the surface of the mould parts have a size which is larger than the means size of the Si3N4 particles. The invention further relates to a method for producing the silicon nitride mould parts.
Abstract: The present invention provides an oxide-base scintillator single crystal having an extremely large energy of light emission, adoptable to X-ray CT and radioactive ray transmission inspection apparatus, and more specifically to provide a Pr-containing, garnet-type oxide single crystal, a Pr-containing perovskite-type oxide single crystal, and a Pr-containing silicate oxide single crystal allowing detection therefrom light emission supposedly ascribable to 5d-4f transition of Pr.