253 results about "Czochralski method" patented technology

The embodiment of the invention provides a Czochralski method crystal growth device and a regulation and control method, and relates to the technical field of crystal growth. The Czochralski method crystal growth device comprises a furnace body, a crucible, a first magnetic field device, a seed rod and a second magnetic field device, the crucible is arranged in the furnace body, and the first magnetic field device is arranged on the outer side of the crucible in a surrounding mode and located in the furnace body. The seed rod is arranged in the furnace body and is spaced from the crucible; the second magnetic field device is arranged on the seed crystal rod and is positioned in the furnace body; wherein the first magnetic field device is used for generating a magnetic field and acting on a melt in the crucible; the second magnetic field device is used for generating a magnetic field and acting on a growth interface of the melt. The Czochralski method crystal growth device can effectively inhibit convection of melt, so that solute distribution is uniform, and crystal defects are reduced; and the crystal structure can be optimized, and accurate regulation and control of solute are realized, so that the quality and the performance of the crystal are integrally improved.

The invention relates to a czochralski method-based crystal growth interface shape detection method and device. The method comprises the steps that: a seed crystal temperature T and an interface electromotive force U at the same time in a crystal growth process are collected, and a T-U curve of the interface electromotive force U changing with the seed crystal temperature T is obtained; the change trend of the shape of a crystal growth interface in real time is judged by observing the deviation between the T-U curve and a reference line, wherein the reference line is a straight line passing through the starting point of the T-U curve, and the slope of the straight line is the Seebeck coefficient of the crystal. The invention also relates to a device used by the method. The detection method provided by the invention can detect the change trend of the shape of the crystal growth interface in real time in the crystal growth process, and can be applied to Czochralski method growth equipment for various single crystals such as lithium niobate, lithium tantalate, sapphire, yttrium aluminum garnet and the like.

The invention relates to the technical field of photovoltaic crystal growth, in particular to a method for improving the axial resistance uniformity of an antimony-doped silicon single crystal and the antimony-doped silicon single crystal. The method provided by the invention comprises the following steps: growing the antimony-doped silicon single crystal by adopting a czochralski method, and at an equal-diameter stage, controlling the furnace pressure to be 4-13torr; in the czochralski method, after leading and releasing are failed or growth of a single antimony-doped silicon single crystal is completed, supplemental doping of an antimony element is carried out according to the volatilization amount of the antimony element. In the method disclosed by the invention, the tail resistance and the head resistance of the prepared antimony-doped silicon single crystal are kept highly consistent by controlling the furnace pressure at the equal-diameter stage, regulating and controlling the volatilization rate of the antimony element, combining the segregation phenomenon of the antimony element in silicon and determining the supplementary doping time of the antimony element.

To provide a method for growing a silicon crystal without substantially including defects.SOLUTION: A method for growing a single crystal silicon ingot by the continuous Czochralski method is disclosed. A melt depth and heat conditions are fixed during growth since a silicon melt is continuously replenished as the silicon melt is consumed; a crucible position is fixed; a critical v / G is determined by a hot zone structure; the continuous replenishment of silicon to the melt during the growth can grow an ingot at a fixed pulling speed coincident with the critical v / G while growing the substantial part of an ingot main body; and the continuous replenishment of silicon is achieved by periodical or continuous nitrogen addition generating a nitrogen doped ingot.SELECTED DRAWING: Figure 5

The invention discloses a crystal growth device and a crystal growth method for gallium oxide crystal downward growth, and belongs to the technical field of gallium oxide single crystal preparation. The device comprises a crucible, an upper shaft, a heating mechanism and a heat preservation mechanism, the crucible is composed of a metal layer and an isolation layer arranged on the inner side wall of the metal layer, an opening is formed in the top of the metal layer, the thermal expansion coefficient of the side, away from the metal layer, of the isolation layer ranges from 0.5 * 10 <-6 > k <-1 > to 2.5 * 10 <-6 > k <-1 >, and the thermal expansion coefficient of the isolation layer is gradually increased outwards from the side, away from the metal layer, of the isolation layer. The rising rate is 2 * 10 <-6 >-3 * 10 <-6 > k <-1 > / mm; the upper shaft is arranged above an opening of the crucible and can lift and rotate relative to the crucible, a seed crystal support is arranged below the upper shaft, a first cooling pipeline is arranged in the upper shaft, and a second cooling pipeline is arranged in the seed crystal support. The crystal growth device breaks through the limitation of a traditional Czochralski method, a casting method and a Bridgman method, realizes downward growth of crystals, and can reduce the influence of crucible metal impurities on the crystals, so that gallium oxide single crystals with high quality, large size and high yield are obtained.

The utility model relates to a bottom heater for improving the material melting efficiency of a single crystal furnace, which belongs to the technical field of a thermal field for producing single crystal silicon by a czochralski method and comprises a heating body and two foot plates which are symmetrically arranged left and right, are respectively positioned on two opposite sides of the heating body and are connected with the heating body; the heating body comprises a first heating body and a second heating body which are symmetrically arranged in the vertical direction; the middle of the foot plate extends and protrudes towards the center of the bottom heater to form an arc-shaped plate, and electrode holes are formed in the arc-shaped plate. The first heating body comprises a first heating unit, a second heating unit and a third heating unit, the first heating unit and the third heating unit are symmetrically arranged on the left side and the right side of the second heating unit, and the outer side of the first heating unit and the outer side of the third heating unit are each of a step-shaped structure. The bottom heater is simple in structure, high in heating power and uniform in heating, the occurrence rate of arcing and sparking of the bottom heater and the heat preservation cylinder caused by external factors is effectively reduced, the service life of the bottom heater is prolonged, the service life of a thermal field is prolonged, and the stability of the thermal field is improved.

The invention discloses equipment for growing large-size gallium oxide crystals and a growing method, and relates to the technical field of crystal growing equipment.The equipment comprises a single crystal furnace body, and the single crystal furnace body comprises a seed crystal lifting and rotating mechanism; the heat preservation device can be arranged in the single crystal furnace and comprises a heat preservation container and a heat preservation top plate; the metal crucible can be placed in the heat preservation container; the first driving mechanism is used for driving the metal crucible to rotate; the induction heating coil is sleeved outside the heat preservation container; and the conical surface ring is connected with the output end of the seed crystal lifting and rotating mechanism through a connecting assembly. The growth method comprises the following steps: melting a gallium oxide raw material, descending the conical ring, generating high-quality seed crystals through nucleation control, expanding to a crystal face, lifting the conical ring to perform equal-diameter growth control after the crystal face is in stable contact with the conical ring, and ending after the crystals reach a set size. The twin crystal defect in a traditional guided mode or Czochralski method can be effectively avoided, and crystals with higher quality can be grown.

The invention relates to a method for controlling BMD of a heavily boron-doped substrate and a lightly boron-doped epitaxial wafer through RTP, which belongs to the technical field of silicon wafer processing, and comprises the following operation steps of: 1, drawing a single crystal by adopting a Czochralski method, and doping Bo metal during crystal drawing; and 2, slicing, grinding and thinning, polishing, cleaning and epitaxy processes are carried out. Step 3, dividing the silicon wafers after completion into three groups A, B and C for annealing treatment; and meanwhile, a group of reference silicon wafers without RTP annealing treatment are manufactured. And 4, carrying out low-temperature heat treatment, wherein the low-temperature treatment is used for promoting nucleation of oxygen precipitation. And 5, performing high-temperature heat treatment which is used for promoting the growth of an oxygen precipitation nucleation center in the silicon wafer body so as to form high-density oxygen precipitation and induced defects thereof in the silicon wafer body. The method improves the yield of silicon wafers, greatly shortens the time consumed in the annealing process in the manufacturing of an integrated circuit, meets the actual requirement for low temperature in the manufacturing process of the integrated circuit, reduces the technological process, and saves the cost.

The embodiment of the invention provides a Czochralski method crystal growth device, and relates to the technical field of crystal preparation. The Czochralski method crystal growth device comprises a furnace body, a crucible, a lifting rotating device, a seed rod adjusting device and a seed rod, wherein the crucible is arranged in the furnace body; the lifting and rotating device comprises a lifting and rotating mechanism and a lifting rod, the lifting and rotating mechanism is arranged above the furnace body, and the lifting rod is connected with the lifting and rotating mechanism and located in the furnace body; the seed crystal rod adjusting device and the seed crystal rod are arranged in the furnace body, and the lifting rod, the seed crystal rod adjusting device and the seed crystal rod are connected in sequence; the lifting rotating mechanism is used for driving the lifting rod to lift or rotate, and the seed rod adjusting device is used for driving the seed rod to move relative to the crucible. The seed crystal rod can be directly adjusted in the furnace body, the problem of deviation of the seed crystal rod is solved, and the working efficiency and the crystal growth efficiency are improved; and the conical heat preservation cover is arranged, so that the uniformity and the symmetry of a temperature field can be improved, and the crystal growth quality is improved.

The invention relates to the field of monocrystalline silicon preparation, particularly provides a monocrystalline silicon rod production method based on a czochralski method, and aims to solve the problem of how to improve the crystallization rate of monocrystalline silicon. In order to achieve the purpose, the single crystal silicon rod production method based on the czochralski method comprises the step of adjusting the flow / flow velocity of inert gas and the liquid opening distance from the lower edge of a guide cylinder to the liquid level of molten silicon in an equal-diameter growth stage based on the equal-diameter growth length of single crystals. On the basis of the equal-diameter growth length of single crystals, the flow / flow velocity of inert gas and the liquid opening distance from the lower edge of a guide cylinder to the liquid level of molten silicon are adjusted, so that the heat convection phenomenon between the inert gas and the molten silicon is controlled, the longitudinal temperature gradient in the single crystal furnace is further controlled, and sufficient heat dissipation capability in crystal growth is ensured; the heat released when the molten silicon is converted into the solid silicon is taken away in time, so that the necessary supercooling degree is formed on the interface of the molten silicon and the solid silicon, the single crystal has enough growth power to keep normal growth, and the crystal forming rate of the single crystal is improved.

The present application relates to a kind of methods and applications of growing bismuth-doped rare-earth iron garnet BRIG crystal by guided mode pulling-top seed crystal method.For solving the problems of large internal stress, many defects, difficult to prepare thick film of single crystal in the current liquid phase epitaxy method of growing BRIG crystal;And the problems of long growth cycle, difficult to obtain seed crystal in top seed crystal method, the present application combines the fast growth of guided mode pulling crystal and the high-quality single crystal growth of top seed crystal method, and invents guided mode pulling-top seed crystal method to realize the fast growth of high-quality BRIG single crystal.First, the large-size doped rare-earth iron garnet crystal with high lattice matching and similar composition is quickly grown by guided mode pulling method, which is cut into centimeter-level seed crystal, and high-quality BRIG bulk single crystal is quickly grown by TSSG method.The crystal grown by this method has the advantages of small internal stress, less cracking, good uniformity, fast crystal growth, etc., and has obvious advantages in high-performance magneto-optical isolator.

The invention relates to a 4-inch low-dislocation indium antimonide lt; 211gt, 211gt; the invention discloses a preparation method of directional single crystals and belongs to the technical field of photoelectric materials. According to the method, a Czochralski method is adopted to grow the single crystal, a resistance furnace is arranged on the periphery of an induction coil of a heating device, and by accurately controlling heating conditions, designing a proper temperature field in a growth chamber and further combining growth conditions such as the state of a solid-liquid interface, the pulling speed, the rotating speed and particularly the shoulder expanding angle in the crystal growth process, the single crystal is obtained. The longitudinal temperature gradient in the crystal growth process is reduced, and the dislocation density of the large-size indium antimonide single crystal with the diameter of 4 inches can be obviously reduced, so that indium antimonide is enabled to be lt; 211gt, 211gt; the dislocation density of the directional single crystal is less than 100 / cm < 2 >.

The invention relates to a silicon single crystal drawing method capable of reducing the resistivity range of a whole silicon single crystal rod, which belongs to the technical field of wafer processing and comprises the following operation steps of: 1, completely melting a solid silicon material and a doping agent into liquid in a crucible a; and 2, slowly lowering the crucible position in the crucible b to realize that a part of liquid at the bottom of the crucible is slowly solidified into a solid from the bottommost part. And 3, after the crucible in the crucible c is slowly lowered and stopped, seeding, shouldering and equal-diameter operation are carried out. And 4, carrying out an equal-diameter growth stage in the d crucible. And 5, continuously growing the single crystal rod in the e crucible. And 6, finishing silicon single crystal drawing in the crucible f through an ending process. An initial state of'high-concentration melt + low-concentration solid 'is constructed before crystal pulling, and real-time and dynamic dilution compensation is performed on the concentration of a dopant of a main melt, so that the inherent defect of resistivity axial non-uniformity caused by a segregation effect in a traditional Czochralski method is effectively overcome.

The invention relates to a preparation method of a cerium-doped lutetium yttrium silicate crystal, and relates to the technical field of scintillation crystal preparation. Compared with a traditional Czochralski method, the cerium-doped lutetium yttrium silicate is prepared through a flame fusion method, the growth speed of the flame fusion method is 15-20 mm / h, the growth rate is higher, consumable items such as an iridium crucible are not needed, mutual reaction between a high-temperature melt and the crucible is avoided, the cost is effectively reduced, and the cerium-doped lutetium yttrium silicate is obtained. The limitation of a crucible material on preparation of high-melting-point oxide crystals is eliminated, the crystal quality is improved, and the growth period is short.

A method for producing a single crystal using the Czochralski method, comprising the following steps: a step of measuring a space between a melt surface and a lower end of a seed crystal provided above the melt; a step in which the seed crystal is lowered on the basis of the space and the seed crystal is brought into contact with the melt; and a step of growing the single crystal at the lower end of the seed crystal by pulling the seed crystal while maintaining a state of contact with the melt, wherein, in the step of measuring the space between the melt surface and the lower end of the seed crystal, an image of the seed crystal and the melt surface is taken using a camera installed obliquely above the melt surface, an approximate circle of the edge of a real image is generated by approximating a circle from an approximately arcuate edge pattern at a lower end part of a real image of the seed crystal shown in the image taken by the camera, and similarly an approximate circle of the edge of a mirror image is generated by approximating a circle from an approximately arcuate edge pattern at an upper end part of a mirror image of the seed crystal reflected at the melt surface, and the space between the melt surface and the lower end of the seed crystal is calculated based on the distance from the center coordinates of the approximation circle of the edge of the real image to the center coordinates of the approximation circle of the edge of the mirror image, and wherein in the step of measuring the space between the melt surface and the lower end of the seed crystal, the approximate circle of the edge of the real image positioned above the approximate circle of the edge of the mirror image is obtained after the approximate circle of the edge of the mirror image is obtained from the captured image, and wherein a step in which the approximation circle of the edge of the mirror image is obtained comprises the following steps: a step of determining an upper end position of the mirror image of the seed crystal from a brightness distribution in a first region defined in advance in the captured image; a step of defining a second region including the upper end position of the mirror image of the seed crystal, and detecting an edge pattern of a part of the straight body from the mirror image of the seed crystal by performing a binarization process of the second region; and a step in which a circle is approximated from the edge pattern of the part of the straight body of the mirror image, where a step in which the approximation circle of the edge of the real image is obtained comprises the following steps: a step of setting a position where a difference value of brightness exceeds a predetermined threshold as a lower end position of the real image of the seed crystal when the first area is scanned upward from the center coordinates of the approximation circle of the edge of the mirror image; a step of defining a third region including the lower end position of the real image of the seed crystal, and detecting the edge pattern of the part of the straight body from the real image of the seed crystal by performing the binarization process of the third region; and a step in which a circle is approximated from the edge pattern of the part of the straight body of the real image.

The invention relates to the technical field of crystal growth, and discloses a method and a system for electrochemical in-situ characterization of crystal growth interface area change, and the method comprises the following specific steps: in a crystal growth process by a Czochralski method, measuring impedance between a seed crystal and a crucible containing a melt in real time to obtain an electrochemical impedance spectrum at the growth stage; performing equivalent circuit fitting on the measured electrochemical impedance spectrum to obtain fitting parameters of a corresponding circuit element and calculating equivalent capacitance of a growth interface of the electrochemical impedance spectrum; and calculating the crystal growth interface area through a parallel plate capacitor model based on the equivalent capacitance value. The method solves the problem that the prior art is not suitable for monitoring the crystal growth interface, and has the characteristics of high precision, nondestructive detection, no influence on crystal growth, simple process and controllable cost.

The invention belongs to the technical field of scintillation materials, and particularly relates to a chromium ion doped near-infrared scintillation crystal and a preparation method and application thereof. The chromium ion-doped near-infrared scintillation crystal has a molecular formula of A3B2-xCrxC3O12, x is greater than or equal to 0.005 and less than or equal to 0.1, and after a chromium ion-doped ultraviolet-visible light inorganic scintillator is adopted, light is emitted at the wavelength of 650-950 nm and has good wavelength matching with a silicon photoelectric detector. Besides, single crystal growth is carried out by adopting a Czochralski method, the crystal growth process is optimized, the ion doping concentration is regulated and controlled, the scintillation performance of the chromium ion doped near-infrared scintillation crystal in the near-infrared band is improved, the requirement of the chromium ion doped near-infrared scintillation crystal in the radiation detection field is further met, and the problem that an existing scintillation crystal is low in transparency is solved.

The present disclosure provides a single crystal silicon, a method for manufacturing the same, and a silicon wafer, the method comprising: when applying a magnetic field to a raw material melt and pulling up the single crystal silicon by a Czochralski method, growing the single crystal silicon in such a manner that the magnetic field intensity is controlled to 2000-3000 gauss. The silicon single crystal thus grown has an oxygen concentration of 5.6 ppma or more and 8.5 ppma or less, an RRG in a crystal cross-section orthogonal to the growth direction of the silicon single crystal of 1% or less, a low oxygen concentration, and high uniformity of radial resistance distribution.

The invention provides a crystal pulling process control method, a single crystal silicon rod process control device and a crystal pulling system.The method comprises the steps that a multi-physical-field coupling numerical model of a silicon melt in a single crystal furnace is constructed and used for reflecting the coupling relation among a pulsating velocity field, a temperature field and an electromagnetic field in the silicon melt; according to a preset simulation method and the multi-physics field coupling numerical model, a plurality of characteristic parameters corresponding to the silicon melt under a plurality of process conditions and a plurality of magnetic field structure parameters are generated, and the characteristic parameters are used for representing melt flow characteristics; and determining a target process condition and a target magnetic field structure parameter according to the plurality of characteristic parameters, the plurality of process conditions and the plurality of magnetic field structure parameters, and controlling the single crystal furnace to perform a crystal pulling process under the target process condition and the target magnetic field structure parameter. According to the method, the problem that the crystal quality cannot be guaranteed due to a czochralski method silicon single crystal rod growth process in the prior art is solved.

The invention discloses a crucible and a temperature field structure for growing crystals by a Czochralski method, the crucible is a cylinder with an open upper end and a closed lower end, the crucible sequentially comprises a crystal growth area, a transition area and a heat preservation area from top to bottom, the transition area and the heat preservation area are used for accommodating a melt, and the transition area and the heat preservation area are communicated with the crystal growth area. The transition area and the heat preservation area are buried in a zirconium sand layer of the temperature field structure during crystal growth, the crystal growth area is used for crystal growth, the heat preservation area and the crystal growth area are both equal-diameter cylinders, the diameter of the heat preservation area is smaller than that of the crystal growth area, the transition area is connected between the heat preservation area and the crystal growth area, and the transition area is connected with the heat preservation area. The transition area is a conical barrel with the upper end large in diameter and the lower end small in diameter. According to the invention, the problem that the spontaneous crystallization phenomenon of a melt easily occurs at the bottom of a large-size crucible for growing large-size crystals in the prior art is solved, and stable growth of the large-size crystals is ensured.

The invention provides a method for promoting growth of dysprosium scandate single crystals, which comprises the following steps: preparing raw materials: uniformly mixing the raw materials, and putting into a crucible; setting growth conditions: putting the crucible filled with the raw materials into a high-temperature furnace, and setting temperature gradient, pressure and growth speed; growing by a lifting method: in the growth process, slowly lifting the seed crystal from the molten raw material at a constant speed through a lifting device, and controlling the cooling rate of the crystal to promote the growth of the single crystal; real-time weighing monitoring: in the upward lifting process, carrying out real-time weighing monitoring on the growing single crystal by using a high-precision weighing device, and adjusting growth parameters to maintain the stability and uniformity of the quality of the single crystal; compared with the prior art, the method has the following beneficial effects that by controlling the growth speed and the temperature gradient, defects and internal stress caused by thermal stress in the crystal growth process can be effectively reduced, and the integrity and the mechanical strength of the crystal are improved.

The invention provides a czochralski method monocrystalline silicon preparation method and a matched growth system. According to the Czochralski method monocrystalline silicon preparation method, a stabilization treatment step is executed after material melting is finished, the stabilization treatment step comprises a magnetic field closing stage and a magnetic field opening stage, and the lifting movement tracks of a quartz crucible in the two stages are the same and the rotation directions are opposite. According to the technical scheme, two-stage stabilization treatment of closing and opening of the magnetic field is set after material melting, and preferably, the lifting track, the total displacement and the rotation rate of the quartz crucible in the two stages are consistent in rate and movement and are opposite in direction, so that impact and scouring on the quartz crucible are reduced, high-temperature softening deformation is relieved, and chemical reaction of molten silicon and the crucible is inhibited; and the crucible loss is delayed.

The invention relates to the technical field of monocrystalline silicon production. The invention provides a shouldering control method for single crystal silicon production based on a czochralski method in order to solve the problems that in the prior art, detection hysteresis exists, and a shouldering opening cannot be pre-judged in advance. According to the method, a prediction model is trained based on static process data and dynamic process data, and then the opening moment and the opening size of the shouldering are predicted by using the trained prediction model. Static process data and dynamic process data are analyzed through a prediction model, an advanced prediction mechanism is achieved, predicted values of the shouldering splitting time and the opening size are given before shouldering opening, the process can be adjusted in time, the unstable condition in the shouldering process is solved, and the detection hysteresis quality is improved. The production stability and the process matching are ensured; manual intervention can be reduced, the technology is intervened in advance according to the prediction result, and frequent adjustment of technological parameters by technologists can be reduced.

A silicon single crystal is provided having markings indicating the boundaries of each crystal block, while a silicon single crystal is grown by the Czochralski method in which a melt is intermittently doped with a subdopant to form a plurality of single crystal blocks along the axial direction and the type and resistivity of each crystal block are controlled. It comprises a plurality of single crystal blocks 1 formed continuously in the direction of the crystal axis, each having a first resistivity within a predetermined range of variation in the direction of the crystal axis, and a high resistivity layer 2 having a second resistivity with a peak value having a tip protruding beyond the predetermined range.

The invention belongs to the technical field of metal material processing, particularly relates to a preparation method of a metal single crystal seed crystal, and belongs to the technical field of single crystal material preparation and crystal orientation control. The method comprises the following steps: selecting an original seed crystal, heating and melting high-purity metal, carrying out single crystal growth by adopting a czochralski method, carrying out crystal orientation analysis and labeling, directionally cutting out the seed crystal and the like. According to the method, through multiple times of shouldering / necking and X diffraction analysis, natural preferred growth of crystals and clear calibration of later crystal orientation are achieved, crystal orientation control is facilitated, the prepared single crystal metal rod has the large size (the diameter is 3-4 inches, and the length is 300 mm), multiple seed crystals can be obtained through repeated cutting, and the material utilization rate can be increased; the grain boundary and dislocation density is reduced in the continuous crystal orientation selection process, so that the crystal integrity is excellent; seed crystals in various growth directions can be obtained through directional cutting, different process requirements can be met, and the process compatibility is good.

The invention relates to a method for pulling a single crystal from a melt consisting of silicon and a dopant according to the Czochralski method, comprising the following steps in a given sequence: a) performing a time-dependent computer simulation of a predetermined crystal pulling process having a predetermined dopant concentration (C) in the melt, with the aim of obtaining a temperature gradient and a dopant gradient for each time increment t, wherein the two gradients are determined at the interface between the crystal and the melt in the normal direction of the melt interface, b) determining a maximum dopant concentration (Cmax) in the melt, and c) pulling up a single crystal having a dopant concentration less than the determined maximum dopant concentration (Cmax), characterized in that a parameter (CS) is calculated for each time increment t, which is determined by formula, wherein the parameter fCS is determined from the product of the average concentration (C) of the dopant in the melt, the density of the silicon melt, the Avgamde constant, the molar mass of the silicon and the slope of the liquidus, and then generating an average value of the values obtained for the parameter (CS) wherein only those values having the (CS) value less than zero are included, and determining the maximum dopant concentration (Cmax) by adapting the above defined dopant concentration (C) until the magnitude equals zero.

The invention relates to a single crystal furnace and a control method thereof. The single crystal furnace comprises a furnace body; the crucible is arranged in the furnace body; the water cooling screen is positioned above the crucible; the guide cylinder is arranged in the furnace body and surrounds the peripheral side of the water cooling screen; and the electromagnetic heating piece is arranged on the peripheral side of the water cooling screen in a surrounding mode and located on the inner side of the flow guide cylinder, the electromagnetic heating piece is further located at the end, close to the crucible, of the water cooling screen, synchronously ascends and descends along with the water cooling screen and the flow guide cylinder, and the electromagnetic heating piece is used for heating a solid-liquid interface between the silicon liquid and the crystal bar. Therefore, the electromagnetic heating element can locally heat the silicon liquid, so that a supercooling area generated on the surface of the silicon liquid due to too high pulling speed in the growth process of the czochralski silicon single crystal is eliminated, the crystal twisting phenomenon is inhibited, the uniformity and high quality of crystal growth are ensured, the yield of the crystal can be ensured, and the uniformity of a thermal field is ensured.

The invention relates to a method for growing a bismuth-doped rare earth iron garnet BRIG crystal by adopting a guided-mode pulling-top seed crystal method and application of the bismuth-doped rare earth iron garnet BRIG crystal. The invention aims to solve the problems of large internal stress, many defects and difficulty in preparation of a single-crystal thick film in BRIG crystal growth by a liquid phase epitaxy method at present; in order to solve the problems of long growth cycle, difficult seed crystal acquisition and the like of a top seed crystal method in the prior art, the invention combines the rapid growth of crystals by a guided mode pulling method and the high-quality single crystal growth by the top seed crystal method, and the guided mode pulling-top seed crystal method is invented to realize the rapid growth of the high-quality BRIG single crystal. The method comprises the following steps: firstly, rapidly growing a large-size rare-earth-doped iron garnet crystal which is high in BRIG crystal lattice adaptation degree and relatively close to BRIG in components by adopting a guided-mode pulling method, cutting the large-size rare-earth-doped iron garnet crystal into seed crystals of more than centimeter level, and rapidly growing a high-quality BRIG blocky single crystal by adopting a TSSG method. The crystal grown by the method has the advantages of small internal stress, less cracking, good uniformity, fast crystal growth and the like, and has obvious advantages in high-performance magneto-optical isolators.

A method for measuring distance between lower end surface of heat shielding member and surface of raw material melt, the method including providing the member being located above the melt, when a silicon single crystal is pulled by the Czochralski method while a magnetic field is applied to the melt in a crucible, the method including: forming a through-hole in the member; measuring distance between the member and the melt surface, and observing position of mirror image of the through-hole with fixed point observation apparatus, the mirror image being reflected on the melt surface; then measuring a moving distance of the mirror image, and calculating distance between the member and the melt surface from a measured value and the moving distance of the mirror image, during the pulling of the crystal. The distance between the member and the melt can be precisely measured by the method.

The invention discloses a high-impedance near-zero-temperature-drift high-temperature piezoelectric crystal material and a growth method and application thereof, and belongs to the technical field of piezoelectric crystal growth. The chemical formula of the high-impedance near-zero-temperature-drift high-temperature piezoelectric crystal material is ErxGd1-xCa4O (BO3) 3, x is equal to 0.1-0.3, large-size high-quality single crystals can be obtained through growth by adopting a conventional pulling method, the growth process is simple, and processing is easy. The effective longitudinal piezoelectric constant d33 of the piezoelectric special-shaped element made of the crystal material can reach 6.5-7.0 pC / N; the effective shear piezoelectric constant d26 can reach 8.5 to 10.0 pC / N; the resistivity can reach 106 omega.cm at the high temperature of 1000 DEG C; the change rate of the piezoelectric constant in a range from room temperature to 1000 DEG C is below 5%, and the piezoelectric ceramic has near-zero temperature excursion characteristics and high temperature resistance.