419 results about "Single crystal growth" patented technology

The invention belongs to the technical field of single crystal growth equipment, and particularly relates to a seed crystal clamping assembly, in particular to a seed crystal pulling assembly, a silicon carbide single crystal growth device and a use method of the silicon carbide single crystal growth device. The seed crystal lifting assembly comprises a lifting rod and a lifting rod, a rotating head; wherein a cavity is formed in the wall body of the rotating head, and a groove is formed in the middle of the rotating head; and fan blades are fixedly arranged in the grooves. The fan blades are arranged in the rotating head, the unique airflow channel is designed, the lifting rod rotates to drive the fan blades to work, and forced airflow circulation is formed, so that the problem that the radial temperature difference of a crystal growth face is large is solved, back heat dissipation of seed crystals is remarkably improved, and the interface stability of crystal growth is improved. And meanwhile, the growth speed can be directly regulated and controlled in time by adjusting the rotating speed of the lifting rod, so that the growth efficiency and the crystal quality are synergistically improved.

The utility model relates to the technical field of single crystal preparation by a liquid phase epitaxy method, in particular to a leading forced convection introducing device for single crystal growth by a resistance heating LPE method, which comprises a graphite crucible and a graphite heating component arranged on the outer side of the graphite crucible, one end of the graphite seed crystal rod extends into the graphite crucible and is connected with the graphite seed crystal support; the seed crystal is adhered to the bottom surface of the graphite seed crystal support; the graphite annular turbofan is arranged in the graphite crucible; the graphite annular turbofan is connected with the graphite seed rod through a jackscrew clamp; the other end of the graphite seed crystal rod is externally connected with a seed crystal lifting and rotating mechanism; and the graphite seed crystal rod drives the seed crystal and the graphite annular turbofan to do lifting and rotating motion. According to the device, the influence of adverse convection on the whole flow field is weakened, and the controllability of the whole flow field can be improved; and meanwhile, an ideal temperature field for growing high-quality silicon carbide crystals in the growth cavity is ensured.

The invention discloses a super-large-scale silicon single crystal growth method based on a high-temperature superconducting magnetic control technology, and relates to the technical field of silicon single crystal growth, and the method comprises the following steps: setting and calibrating an initial magnetic field intensity, and combining a gradient graphite felt heat conductivity coefficient function to optimize temperature field uniformity; a dynamic magnetic field regulation and control mechanism is introduced in the melt stage, melt convection is inhibited through flow velocity-magnetic field joint control, and oxygen concentration monitoring is synchronized; a multi-physics coupling simulation and multi-objective optimization algorithm is adopted in the crystal growth stage, the magnetic field intensity, the heating power and the crystal pulling parameters are adjusted in real time, and the oxygen content and the growth rate are balanced; and the tail stress is relieved through a gradient field reduction technology, and finally, the low-defect and high-uniformity silicon single crystal is obtained. Melt flow and temperature field uniformity are accurately regulated and controlled through a high-temperature superconducting magnetic control technology, dynamic monitoring and a multi-target optimization algorithm are combined, the growth quality of silicon single crystals is remarkably improved, the defect rate and energy consumption are reduced, and meanwhile efficient and stable production of large-size crystals is achieved.

The invention discloses a preparation method of a carbon-coated single-crystal sodium ferric pyrophosphate positive electrode material, which is specifically implemented according to the following steps: step 1, dissolving sodium salt, ferric salt and phosphate in deionized water in proportion, then adding a carbon source into the solution, and uniformly stirring to obtain a mixed solution; step 2, fully drying the mixed solution obtained in the step 1 to obtain precursor powder; and 3, carrying out heat treatment on the precursor powder in a protective atmosphere, and cooling to obtain the carbon-coated single-crystal sodium ferric pyrophosphate positive electrode material. The invention also discloses a coating prepared by the method, a single-crystal structure is combined with uniform carbon coating, grain boundary defects are eliminated, conductivity is improved, high specific capacity and long cycle life are realized, single-crystal growth and carbon layer in-situ coating are synchronously realized by a synthesis process, and structural integrity and efficient conductive network construction can be ensured.

The invention provides a czochralski silicon single crystal growth process multivariable monitoring method, and belongs to the technical field of czochralski silicon single crystal growth. Comprising the following steps: synchronously acquiring and pre-processing various process variable time sequence data in a czochralski silicon single crystal growth process to obtain a multivariable time sequence matrix; performing slow feature extraction on the multivariable time sequence matrix by using a multi-scale sliding window strategy, and sequentially constructing a static slow feature matrix and a dynamic slow feature matrix; the static slow feature vector and the dynamic slow feature vector of each time step are spliced into a fusion slow feature vector, all the fusion slow feature vectors form a fusion slow feature matrix, and the fusion slow feature matrix is divided into a fusion training set and a fusion test set; and constructing an auto-encoder network model, and training and testing the auto-encoder network model to obtain a multivariable monitoring result. According to the invention, accurate real-time monitoring of the growth process of the czochralski silicon single crystal in a complex environment can be realized.

The invention discloses a silicon single crystal growth interface deformation detection method, system, equipment and medium, and relates to the technical field of silicon single crystal growth soft measurement modeling. Comprising the following steps: acquiring a process parameter set in a silicon single crystal production process; the process parameters in the process parameter set serve as nodes, mutual information indexes between the nodes serve as edges, and a graph structure model is constructed; performing multi-layer neighborhood aggregation operation on the graph structure model to obtain initial features; performing attention mechanism operation on the initial features to obtain aggregated features; and carrying out weighting operation on the aggregation characteristics by adopting a long-short-term memory network to obtain a deformation detection result of the silicon single crystal growth interface. According to the method, the modeling expressive power of a complex dynamic process is improved, and the sensitivity and the response speed of an abnormal deformation evolution trend are also remarkably enhanced.

The invention relates to the technical field of semiconductor material growth, and aims to solve the technical problems that the service life of a heating element is shortened due to single atmosphere sharing, the quality is difficult to guarantee due to many crystal defects, the single crystal production cost is high, and the production efficiency is low in the prior art. The invention discloses a single crystal growth device which is characterized by comprising a furnace body, a first chamber, a second chamber, a heating assembly, a growth assembly, an atmosphere isolation and heat conduction assembly, an atmosphere management system and a central control system, the atmosphere isolation and heat conduction assembly is used for separating the furnace body into a first cavity and a second cavity which are isolated in an airtight mode, and efficient heat transfer is achieved. By the adoption of the scheme, atmosphere structure separation and combined crucible design can be achieved, high quality and high purity of crystals are guaranteed, meanwhile, the service life of a heating element is effectively prolonged, and the operation cost is remarkably reduced.

The invention belongs to the technical field of lithium ion battery materials, and discloses a preparation method of a high-first-effect small-particle single-crystal ultrahigh-nickel ternary positive electrode material. The method comprises the following steps: firstly, uniformly mixing an ultrahigh nickel ternary precursor with a lithium source and a tungsten source, performing mechanical densification and pressing to obtain a blocky solid, and then performing four-section program temperature control calcination to obtain a target material. The interface fusion resistance of single crystal growth can be reduced through mechanical densification; a part of the tungsten element forms a Li2WO4 coating layer, and a part of the dopant phase replaces Ni < 2 + >, so that grain growth can be inhibited, a crystal structure can be stabilized, and the first effect is improved; and the microstructure of the material can be accurately regulated and controlled through four-section temperature-controlled calcination. Through a coating-doping-single crystallization synergistic strategy, the electrochemical performance of the material in liquid and sulfide-based all-solid-state batteries is remarkably improved, the process is controllable, and the application prospect is wide.

The invention provides a method for improving COP defects based on crystal bar temperature gradient control, and relates to the technical field of monocrystalline silicon production, the method comprises the following steps: collecting temperature distribution data of a crystal bar growth interface and surface in real time, and reading a crystal bar pulling speed in real time; calculating an instantaneous V / G value according to the temperature distribution data and the pulling speed of the crystal bar; comparing the instantaneous V / G value with a preset V / G critical value; and according to the comparison result, adjusting the inward or outward opening angle of the scales on the scale type radiation adjusting device arranged between the crystal bar and the heat shield, so as to adjust the crystal bar temperature gradient G by adjusting the heat radiation reflected to different positions of the crystal bar, and further adjust the V / G value. According to the scheme, the thermal radiation reflection path can be dynamically changed according to the actual condition of the single crystal growth stage, so that the temperature gradient distribution of the single crystal growth stage is adjusted, the V / G value is further adjusted to reduce the generation of COP defects, and the quality of the single crystal is improved.

The invention discloses a Czochralski silicon single crystal growth process diameter detection system and method based on machine vision. The system comprises an optical data acquisition module, an image processing module, a core detection module and a control output module. The method comprises the following steps: firstly, acquiring a growth image of a crystal in a single crystal furnace through an obliquely mounted CCD (Charge Coupled Device) camera, and synchronously acquiring furnace temperature data and a nominal diameter of the crystal; searching an optimal solution of dynamic multi-region segmentation through a dynamic multi-threshold segmentation unit, extracting a highlight halo from a background, and reconstructing an edge detection model through a four-direction fractional order differential operator; an improved parallel chord center line theorem is adopted to obtain an ellipse center, and a two-stage optimization strategy is adopted to obtain an ellipse diameter; and finally, an effective detection result is output to a control system, and a data packet is uploaded in real time through the industrial Internet of Things gateway. The method is high in measurement precision, high in measurement efficiency and short in consumed time, online detection of the diameter of the 300mm-level crystal is realized, and core technical support is provided for closed-loop control of crystal growth.

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 belongs to the technical field of crystal growth, and relates to a method and a system for regulating and controlling the crystal orientation in real time in a micron-sized single crystal growth process, which are used for realizing real-time microscopic monitoring on the crystal growth state by collecting inherent physical signals of a crystal growth interface area and generating original signal data. Extracting characteristic parameters associated with crystal orientation deviation from the original signal data, generating a crystal orientation deviation characteristic vector, inputting the crystal orientation deviation characteristic vector into a preset mapping model, generating a crystal orientation deviation quantitative index to calculate a local thermal field regulation and control instruction, the micro heat source array is driven to apply a local thermal field gradient to a target area of a crystal growth interface so as to guide the crystal orientation to return, so that global thermal stress fluctuation and new crystal defect hidden dangers caused by traditional large-range thermal field adjustment are avoided, flexible fine adjustment of the crystal orientation is realized, the internal quality and uniformity of crystal growth are greatly improved, and the crystal growth efficiency is improved. Therefore, the single crystal quality and the yield are obviously improved.

The invention provides a semiconductor silicon single crystal growth value prediction method based on event trigger learning, and belongs to the technical field of silicon single crystal growth prediction. Comprising the following steps: constructing a value state space model according to a silicon single crystal growth mechanism; embedding the value state space model into a long short-term memory network to construct a network model; an attention mechanism is introduced into the network model, weighted fusion processing and physical constraint mapping processing are carried out in sequence, and the network model is constructed; based on an event triggering learning mechanism, training and adjusting the network model by utilizing historical time sequence data of the semiconductor silicon single crystal growth value to obtain a trained network model; and inputting the technological parameters at the current moment into the trained network model, and predicting the growth value of the semiconductor silicon single crystal at the next moment. According to the method, the accuracy, the real-time performance and the self-adaptive updating capability of semiconductor silicon single crystal growth value prediction can be improved.

The invention discloses a device and a method for inhibiting crucible oxidation and raw material decomposition in gallium oxide single crystal growth, the device comprises a furnace body, an iraurita crucible, a thermal insulation layer, an induction coil, a lifting mechanism and the like, a temperature dynamic regulation and control system is arranged between the iraurita crucible and the thermal insulation layer; the temperature dynamic regulation and control system is used for monitoring the temperature distribution of the iridium crucible and the inner cavity in real time and regulating the heating frequency of the induction coil through feedback temperature; a melt decomposition monitoring system is arranged in the inner cavity close to the iraurita crucible and is used for detecting the gallium atom concentration and oxygen partial pressure change in the inner cavity in real time; and an atmosphere active adjusting system is also arranged in the furnace body. According to the device, the gallium oxide single crystal can be obtained, and the problems of crucible oxidation, melt decomposition and unstable crystal quality caused by a high-temperature environment can be solved; through dynamic monitoring and regulation, the oxidation and corrosion loss of the iraurita crucible is reduced, and meanwhile, the large-size and high-quality beta-Ga2O3 single crystal is obtained.

The invention relates to the technical field of gallium oxide crystal preparation, in particular to a gallium oxide edge-defined film-fed crystal growth quality prediction method based on artificial intelligence. Obtaining multi-source data of gallium oxide edge-defined film-fed crystal growth, wherein the multi-source data comprises process parameters and dynamic data; multi-modal data features are obtained based on data feature extraction of the multi-source data; inputting the multi-modal data characteristics into a multi-modal fusion prediction model to obtain gallium oxide edge-defined film-fed crystal growth quality prediction data; and obtaining optimized process parameters through a genetic algorithm based on the gallium oxide edge-defined film-fed crystal growth quality prediction data. According to the method, stage features are extracted respectively, the process state of each stage can be evaluated in real time, the process root of the final quality problem is traced, the situation that the crystal growth condition cannot be predicted by depending on experience in a traditional method is avoided, comprehensive prediction of crystal growth is achieved, process parameters are fed back, and optimization of the process parameters is achieved.

The invention relates to the technical field of silicon carbide single crystal production, and discloses a seed crystal supporting and protecting structure for growing a silicon carbide single crystal by a liquid phase method, comprising: a seed crystal fixing and supporting rod, which comprises a supporting part and a rod part, the supporting part and the rod part are integrally formed; the silicon carbide seed crystal plate is mounted on the seed crystal fixing and supporting rod; the seed crystal protection ring is mounted on the seed crystal fixing and supporting rod, the upper end surface of the seed crystal protection ring is flush with the upper end surface of the middle supporting part of the seed crystal fixing and supporting rod, and the lower end surface of the seed crystal protection ring is flush with the seed crystal bonding end surface of the silicon carbide seed wafer, so that the flat embedding type layout of the silicon carbide seed wafer is formed. According to the invention, the stability of a seed crystal-melt interface is ensured through the integrally designed seed crystal fixing and supporting rod; the seed crystal protection ring and the convection blocking ring are combined for use, so that triple stable control on a temperature field, a flow field and a concentration field of the edge of the seed crystal is realized; the problems of edge polycrystal parasitism, inclusion defects and interface instability are effectively inhibited, so that the single crystal growth quality and yield are remarkably improved.

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 invention relates to the technical field of single crystal growth, in particular to a single crystal furnace which comprises a furnace body, a crucible assembly, a heating assembly, a guide cylinder and a gas guide assembly, and an exhaust through hole is formed in the furnace body; the crucible assembly is arranged in the furnace body; the heating assembly is arranged in the furnace body, located around the crucible assembly and used for heating the crucible assembly. The guide cylinder is arranged in the furnace body, is positioned above the crucible assembly and is used for guiding shielding gas into the furnace body; the gas guide assembly is arranged in the furnace body, located below the crucible assembly and used for guiding part of the shielding gas to the position below the crucible assembly. The maximum temperature of the bottom of the crucible can be reduced, the temperature difference between the maximum temperature of the bottom of the crucible and upper and lower silicon solutions in the crucible is reduced, and the heat convection phenomenon of the silicon solutions in the crucible is slowed down, so that the concentration of oxygen generated by reaction in the crucible is reduced, the oxygen content of a crystal bar is reduced, the crystal growth quality is effectively improved, and the crystal pulling quality of the crystal bar is improved; and the power consumption of the heater is not increased.

The utility model provides a silicon carbide crystal growth device for improving the spiral dislocation defect. The silicon carbide crystal growth device comprises a crucible body and a plurality of graphite partition plates arranged in the crucible, and the graphite partition plates are arranged at the bottom of a raw material area of the crucible at equal intervals; the graphite clapboards are inserted into the silicon carbide powder at intervals, the heights of the graphite clapboards are in an arithmetic progression, so that the heights of the silicon carbide powder are also in an arithmetic progression, and the heights of the graphite clapboards and the silicon carbide powder in the corresponding areas are gradually reduced in the direction from the small surface area of the seed crystal to the direction far away from the small surface area. In the single crystal growth process, the silicon carbide powder in the graphite partition interlayer is heated to sublimate, and the distance between the surface of the silicon carbide powder and the growth surface of the seed crystal is reduced due to the height advantage of the silicon carbide powder in the graphite partition area with higher height, so that the growth component forms the component density advantage at the surface of the seed crystal in the area; the conversion and movement processes of screw dislocation in the crystal are effectively promoted, and the crystal quality is improved.

The invention discloses a crystal growth device and a crystal growth method adopting a heat insulation plate to adjust a vertical temperature gradient, the heat insulation plate is introduced between a heater and a crystal growth crucible, the relative positions of the heater and the crystal growth crucible are kept immobile, and the temperature gradient in the vertical direction in a growth chamber is adjusted by utilizing the lifting of the heat insulation plate; therefore, solidification and crystallization of the semiconductor melt in the crucible from bottom to top are achieved, and the single crystal growth process is completed. The device and the crystal growth method are suitable for semiconductor crystal materials such as gallium oxide which can be grown by adopting a melt method. Compared with a traditional method that power is reduced from bottom to top through multiple sets of heaters or a crucible is lowered relative to the heaters, the crystal growth method can keep high stability of a thermal field in the crystal growth process and linear pushing of a crystal growth interface, and therefore the controllability of crystal growth is improved.

The invention provides an MPCVD microwave single crystal growth pressure control device and growth equipment provided with the same, the MPCVD microwave single crystal growth pressure control device comprises a furnace body and a vacuum pump, and is characterized in that a filter is arranged between the furnace body and the vacuum pump, and two side pipelines for communicating the furnace body with the vacuum pump are arranged at two ends of the filter; the air inlets and the air outlets of the two side pipelines are mutually crossed, and at least one control valve is arranged on each side pipeline. The pressure control device for MPCVD microwave single crystal growth is simple in structure and easy to disassemble and assemble, the stability of airflow and the stability of pressure in the whole process of MPCVD microwave single crystal growth can be guaranteed, dust can be effectively filtered, the effectiveness and safety of pipeline smoothness can be guaranteed, and therefore the quality of diamond MPCVD microwave single crystal growth can be guaranteed. The invention further provides a using method of the pressure control device for MPCVD microwave single crystal growth.

The invention discloses an indium phosphide single crystal growth dynamic thermal field control method based on AI calibration of multiple temperature zones, and relates to the technical field of semiconductor material preparation and artificial intelligence control. According to the method, a multi-temperature-zone thermal field digital twin model is constructed, multi-channel temperature data, heating power data and crystal growth image data in an indium phosphide single crystal growth furnace are collected, and real-time three-dimensional reconstruction of thermal field distribution in the furnace is carried out; with the crystal growth rate, the solid-liquid interface shape and the thermal stress distribution as optimization targets, power adjustment instructions of heaters in all temperature zones are output; an AI calibration module is introduced to correct thermophysical parameters of the digital twin model; deducing a thermal field state at a future moment, compensating a thermal hysteresis effect in advance, and realizing accurate closed-loop control of an indium phosphide single crystal growth process; according to the invention, the problem that the traditional PID control is difficult to cope with nonlinear, strong-coupling and large-lag thermal field change in large-size crystal growth is solved, and the single crystal yield and the lattice quality are remarkably improved.

To provide a method for manufacturing a graphite crucible hard to be exhausted even when put at high temperature.SOLUTION: A method for manufacturing a single crystal growth graphite crucible, capable of growing the single crystal on the main surface of a seed crystal substrate by a sublimation recrystallization method comprises: the molding step of molding a raw material including coke mainly constituted of needle coke and binder pitch; the calcination step of calcining the molded molding to obtain a calcined product; the first impregnation calcination step of performing the impregnation and calcination of additional binder pitch once or more to the calcined product to obtain an impregnation calcination product; the graphitization step of heating and graphitizing the impregnation calcination product at 2000°C or more to obtain a graphitization product; and the second impregnation calcination step of performing the impregnation and calcination of additional binder pitch once or more to the graphitization product.SELECTED DRAWING: Figure 1

The invention discloses a method, a device, equipment and a medium for controlling a Czochralski process, and belongs to the field of Czochralski. Observation variables in the single crystal straight pulling process are obtained and comprise the bright ring outer ring radius, the melt mass and the liquid opening distance. Then, based on a state space model, according to the observation variables, the internal state of the single crystal straight pulling process is estimated, and estimation variables including the estimated crystal radius and the estimated meniscus height are obtained; and then taking the estimated variable as an initial state, determining a predicted change track of an internal state based on a state space model, and generating and executing a control instruction based on the predicted change track by taking a target crystal radius and a target meniscus height as control targets. According to the scheme, through multi-variable collaborative estimation and predictive optimization, the problems that variables are strongly coupled, the internal state cannot be directly measured, control lags and the like in the czochralski single crystal growth process are solved, technical support is provided for preparing high-quality large-size single crystal silicon, and the crystal diameter control precision is improved.

The invention discloses a novel gallium nitride reaction chamber heating structure and a use method thereof. The novel gallium nitride reaction chamber heating structure comprises a high-temperature furnace (103), a carrying table (106) and a gallium boat (101), the thermocouple A (102) is arranged on the side wall of the high-temperature furnace and is used for detecting the temperature in the furnace; the quartz cover (104) covers the lower part of the gallium boat and the carrying platform so as to form a reaction chamber; the manipulator (108) is mounted at the bottom of the high-temperature furnace, and the top of the manipulator bears the carrying table; the thermocouple B (109) is arranged in the manipulator and is used for detecting the temperature of the carrying platform; and the resistance wire (110) is mounted at the top of the manipulator and is used for heating the carrying table. The method has the beneficial effects that the corrosion of the pipe wall of the gas outlet of the gallium boat can be effectively reduced, the service life of the gallium boat is prolonged, the epitaxial film defects are reduced, and the single crystal growth quality is improved.

The invention belongs to the field of single crystal growth, and particularly relates to a novel single crystal with ferroelectricity and ferromagnetic orderliness at room temperature and a growth method. Comprising the following steps: grinding a composition 1 and a composition 2 in an aluminum oxide mortar, putting into a platinum crucible, putting the platinum crucible into an aluminum oxide crucible, putting the aluminum oxide crucible into a single crystal growth furnace, adjusting a temperature program, cooling to room temperature, and taking out the platinum crucible; and S2, putting the platinum crucible taken out in the step S1 into a beaker, adding dilute nitric acid, and carrying out ultrasonic cleaning to obtain the novel ordered single crystal with ferroelectricity and ferromagnetic at room temperature. The high-temperature melting method is adopted for the first time to grow the novel single crystal with ferroelectricity and ferromagnetic ordered state at the same time under the room temperature condition, and the operation method is simple and easy to implement.

The utility model belongs to the technical field of silicon carbide single crystal growth, and particularly relates to a growing device for growing silicon carbide single crystals in batches, which comprises a heating furnace, a lifting platform is arranged in a heating cavity of the heating furnace, a plurality of crucible components are uniformly arranged on the lifting platform at intervals, and each crucible component comprises a crucible main body. A flow guide sleeve is arranged on the upper side of the crucible main body, a circular ring is arranged on the upper side of the flow guide sleeve, a crucible cover is arranged at the top of the crucible main body, seed crystals are arranged on the lower side of the crucible cover, and tantalum foils are arranged on the lower side of the crucible cover, the inner side of the crucible main body and the inner side of the flow guide sleeve; according to the invention, a plurality of small-size silicon carbide single crystals can be simultaneously grown in the medium-frequency induction graphitization furnace, so that the production cost is reduced while the problem of overlarge longitudinal temperature gradient during growth of large-size single crystals is avoided.

This utility model discloses a heating device that facilitates single crystal growth, belonging to the field of single crystal heating technology. It includes a base and a furnace body. The bottom of the furnace body passes through and is fixedly connected to the top wall of the base. A crucible is rotatably installed inside the furnace body. A heat insulation cylinder is fixedly connected to the top wall of the furnace body to prevent internal temperature leakage. It also includes a heater and a height adjustment component. The heater is fitted around the crucible. The height adjustment component includes a ring, a screw, and a screw sleeve. The top of the ring is fixedly connected to the bottom of the heater, and one end of the bottom of the ring is fixedly connected to the top of the screw. This heating device, which facilitates single crystal growth, allows for adjustment of the heater height through the height adjustment component, ensuring the heater height is always controlled within a suitable range. This solves the problem that most existing single crystal heating devices are inconvenient to adjust the heater height, have poor control over the single crystal thermal field, and are prone to causing thermal stress defects in the crystal rod.

The application discloses a method for preparing a large-size single crystal by a crucible-free method and belongs to the technical field of semiconductor material preparation. The method comprises the following steps: a. providing a plurality of small-size seed crystals, wherein the seed crystals are single crystal seed crystals; b. splicing the plurality of small-size seed crystals to form a large-size composite seed crystal; c. performing single crystal growth on the composite seed crystal, wherein in the single crystal growth process, a single crystal region with a growth advantage gradually expands and dominates through crystal direction competition; d. processing the grown single crystal region with the expanded and dominant single crystal into a new seed crystal for splicing and growth in the next round; and e. repeating steps b-d to obtain a large-size single crystal. The method ingeniously bypasses the problem of a traditional expanding process through a strategy of "dividing the whole into parts and iterative optimization", can prepare a high-quality single crystal with a size far greater than that of an initial seed crystal on the basis of a small-size seed crystal at a low cost, and provides a brand-new and effective technical path for a size breakthrough of gallium oxide and other single crystals.

To make shading work efficient by improving prediction accuracy for a crucible bottom temperature at which the shading is started.SOLUTION: A method of growing single crystal comprises: an acquisition process 11 of acquiring a crucible bottom temperature in shading operation for each number of times of growth of the single crystal; a prediction process 12 of predicting a crucible bottom temperature at which the shading operation is started as a predicted crucible bottom temperature; and an implementation process 13 of starting the shading operation at the timing when the predicted crucible bottom temperature is reached, wherein the prediction process 12 includes: a first process 12a of selecting a group of most recent n numbers Xn of times of growth of single crystal after the number X of times of growth and a group of crucible bottom temperatures Yn in the shading operation; a second process 12b of finding relational expression (I) Y=aX+b between the number X of times of growth of single crystal and a crucible bottom temperature Y in the shading operation from the selected information groups by a least square method; and a third process 12c of determining, as a predicted crucible bottom temperature Yp, the crucible bottom temperature Y calculated by the number X=p of times of growth to be performed from now in the number X of times of growth of single crystal of the relational expression (I).SELECTED DRAWING: Figure 1