32results about How to "Increased axial temperature gradient" patented technology

The invention provides hot-cold combined casting mould horizontal continuous casting equipment of cupronickel tubing and a technology thereof. The equipment comprises a smelting system for melting metal, a heat insulation system for storing molten metal, a horizontal continuous casting system for casting and shaping and an auxiliary system, wherein in the continuous casting system, the front end of a cold shaping section is provided with a hot shaping section so as to effectively control the solid-liquid interface of a tube billet to be located near the juncture of a cold section and a hot section; a shorter water-cooling copper bush and electromagnetic induction heating are adopted to reasonably design coil structure and the power and the frequency of a heating power supply, reduce electromagnetic constraint force to balance the hydrostatic pressure of a metal fusant, reduce friction between a primary kish and the casting mould, improve the surface quality of the tube billet and prolong the service life of the casting mould. Thus, the inner surface and the outer surface of the tube billet manufactured by the invention have good quality and no defects of orange peel, wrinkles, cracks and the like, net shape continuous casting is realized, the production efficiency and the metal yield are improved and the production cost is obviously lowered.

The invention discloses a guide cylinder capable of shortening the crystal pulling time and improving the crystal pulling speed and a preparation method. The guide cylinder comprises an inverted conical cylinder; the cylinder comprises an outer screen (3) and an inner screen (5); a thermal insulation layer (4) is arranged between the outer screen (3) and the inner screen (5); the guide cylinder is characterized in that the outer screen (3) is prepared from carbon/carbon composite material; the inner screen (5) is prepared from metal molybdenum or metal tungsten; the outer screen (3) is connected with a positioning disc (1) so that the outer screen (3), the inner screen (5), the thermal insulation layer (4) and the positioning disc (1) form an integral structure; and the guide cylinder is produced by the steps of blank production, purification, surface coating and cylinder assembly. The guide cylinder disclosed by the invention has good thermal insulation effect, high strength, long service life and good reflection effect, effectively increases the axial temperature gradient, accelerates the crystal pulling, shortens the crystal pulling time and effectively improves the production efficiency.

The invention discloses a micro-pulling-down crystal growing furnace. The furnace comprises an upper heat-insulating layer and a bottom heat-insulating layer (13) which are arranged from top to bottom, wherein a tubular observation hole (4) is also formed in the bottom heat-insulating layer (13), and the included angle formed by the central axis of the observation hole (4) and the normal of the top surface of the bottom heat-insulating layer (13) is in a range of 45-60 degrees; each of an inner heat-insulating layer, a middle heat-insulating layer and the bottom heat-insulating layer (13) is formed by pressing and calcining zirconium oxide and aluminium oxide in the mass ratio of 1:9. According to the micro-pulling-down crystal growing furnace, the crystal growing condition of a crystal growing interface can be timely observed via the formed observation hole; besides, the effect caused by the observation hole on the temperature field of the crystal growing furnace is low, and the crystal growing yield can be further increased.

The invention discloses a device for improving the pulling speed of czochralski monocrystalline silicon. The device comprises a cylinderical cooling mechanism, a cooling medium inlet pipe and a cooling medium outlet pipe. A method for improving the pulling speed of the czochralski monocrystalline silicon comprises the following steps: firstly, preparing; secondly, heating to melt materials; thirdly, performing intermediate treatment; fourthly, performing equal diameter treatment; fifthly, ending and performing post treatment. The device and the method disclosed by the invention have the advantages that an axial temperature gradient of monocrystalline silicon rods is increased by using the principle that an inert element cooling medium gasifies to absorb heat, and the pulling speed of monocrystalline silicon is improved by 20 percent or above; an upper heat insulating mechanism and the like of a thermal field system are not changed, so that no extra energy consumption is added; the inert element cooling medium is recycled, so that the production cost of the monocrystalline silicon is reduced; the used inert element cooling medium is liquid helium or liquid argon, does not react with a silicon melt and does not affect thermal field components, so the method disclosed by the invention is safer than a conventional method, and the safety of production of the monocrystalline silicon is improved.

The invention discloses a silicon carbide single crystal, a substrate and a preparation method thereof, which belongs to the field of semiconductor materials. The preparation method of the silicon carbide single crystal comprises the following steps: forming a low-temperature region and a high-temperature region in a crucible by virtue of a temperature measuring hole formed in an upper thermal insulation layer group outside the crucible, and transmitting a raw material gas phase in the low-temperature region to the surface of a seed crystal in the high-temperature region by virtue of a physical gas phase transmission method to grow the crystal; wherein the upper heat preservation layer set comprises a second heat preservation layer and a first heat preservation layer which are sequentiallyarranged in the seed crystal direction of raw materials. The first heat preservation layer is provided with a first opening, the second heat preservation layer is provided with a second opening, anda rotary adjusting mechanism rotates the first heat preservation layer and/or the second heat preservation layer to adjust the cross sectional area of a temperature measuring hole formed by the firstopening and the second opening, so that the axial and radial temperature gradient in the crucible in the crystal growth process is adjusted. According to the preparation method of the silicon carbidesingle crystal, the radial temperature gradient in a growth cavity for growing the single crystal can be adjusted; and while the radial temperature gradient is reduced, a certain axial temperature gradient is ensured, and the high-quality silicon carbide single crystal is efficiently prepared.

The invention relates to the technical field of czochralski monocrystalline silicon, and discloses a czochralski monocrystalline silicon growth furnace which comprises a fixed box and a pyrometer. A heat preservation cylinder I is fixedly mounted at the left part of an inner cavity of the fixed box, a heating element is fixedly mounted on the inner wall of the heat preservation cylinder I, and a seed crystal is fixedly mounted on the right side of the top of the fixed box. Through the setting of the growth box, the melting of the polycrystalline silicon is separated from the pulling place of the monocrystalline silicon body; the polycrystalline silicon is continuously melted through the quartz crucible to form a melt to provide a raw material for pulling the monocrystalline silicon body from the interior of the growth box; the quality of the monocrystalline silicon body is prevented from being reduced due to non-uniform thermal field in the quartz crucible; the growth interface temperature in the growth box can be kept within a certain range, and the temperature control difficulty is reduced; meanwhile, the quartz crucible and the growth box are arranged to ensure the sufficiency of raw materials; and through the arrangement of a rotating device, the number of single crystal silicon bodies pulled at a time is increased, and the production efficiency is improved.

The invention discloses a device for preparing a single crystal and a preparation method for a silicon carbide single crystal, belonging to the field of semiconductor materials. The device for preparing the single crystal comprises a crucible, a heating coil group and a heat preservation structure, wherein the crucible forms a growth cavity which comprises a raw material area used for placing rawmaterials and a crystal growth area used for arranging seed crystals; the heating coil group is arranged around the side wall of the crucible and comprises a first coil group corresponding to the rawmaterial area and a second coil group corresponding to the crystal growth area; and the inner diameter of the second coil group is increased in a direction from raw materials to seed crystals. The single crystal growth device provided by the invention can adjust the radial temperature gradient in the growth cavity for growth of the single crystal, can reduce the radial temperature gradient, can guarantee a certain axial temperature gradient at the same time, and can realize high-efficiency preparation of high-quality single crystals.

The invention provides a preparation method and a growth device of an N-type silicon carbide crystal. The method comprises the following steps: (1) placing a raw material in a high-temperature area of a crucible, placing a seed crystal in a low-temperature area of the crucible, recessing the outer wall of the top of the crucible inwards to form an annular gas groove, placing the assembled crucible in a furnace body of a crystal growth furnace, and enabling the annular air groove to be close to a vent hole of the furnace body; and (2) in a crystal growth stage, introducing nitrogen source gas into the furnace body through the vent hole, controlling crystal growth temperature and crystal growth pressure, and enabling the N-type silicon carbide crystal to grow on the seed crystal. The annular gas groove is close to the vent hole of the furnace body, the introduced gas can flow along the annular gas groove, a gas flow speed is high, the gas is diffused into the crucible, heat transmission away from the central axis in the crucible is accelerated, the radial temperature gradient of the crucible is reduced, and crystal growth quality is improved.

The embodiment of the invention discloses a water cooling screen, which comprises a water cooling screen body and a cooling water path arranged in the water cooling screen body, wherein the cooling water path at least comprises two cooling water path branches, the cooling water path branches are mutually independent, and the cooling water path branch at the corresponding position is in a low-temperature state when a silicon rod rises to a certain height by controlling the water supply time or the water supply flow of cooling water. According to the water cooling screen provided by the invention, the heat exchange rate of the water cooling screen can be improved through time-sharing and component water supply, so that the axial temperature gradient during growth of a silicon rod is increased, and the growth speed of monocrystalline silicon is effectively improved. The embodiment of the invention also discloses a monocrystalline silicon growth device and a monocrystalline silicon growth method.

The invention discloses a water-cooling dynamic heat flow sensor. The sensor comprises a heat flow sensor body which comprises a heat transfer probe and a T-shaped cavity which are coaxially and integrally arranged, two butt-joint thermocouple wires which are arranged on the heat transfer probe in a penetrating manner, and a water cooling device arranged at the lower end of the T-shaped cavity. The heat flow sensor is novel in structure, stable in operation and low in preparation process difficulty, simplifies the design of a test water inlet and outlet channel, and facilitates the miniaturization design of the heat flow sensor; and under the water cooling effect of the T-shaped cavity, the axial temperature gradient of the whole heat flow sensor body is obviously increased, the axial temperature difference signal-to-noise ratio is improved, and the subsequent heat flow calculation precision can be improved. A water cooling device with high cooling efficiency is adopted at the tail part of the T-shaped cavity so that a high-heat-flow long-time test can be realized; and in combination with a hybrid dynamic heat flow test method containing calibration correction, the test accuracy of the designed water-cooling dynamic heat flow sensor is ensured, the heat flow test response speed is improved, and a foundation is laid for a dynamic high heat flow long-time test.

The invention provides a device suitable for large size single crystal pulling speed accelerating and head radiation. The device comprises a refrigeration device main body, a water inlet pipeline, anda water outlet pipeline; the water inlet pipeline and the water outlet pipeline are connected with the refrigeration device main body respectively, it is convenient for circulation flowing of coolingmedium in the refrigeration device main body; the refrigeration device main body is provided with a plurality of sight holes along the direction from a single crystal furnace cover to a crucible successively; the single crystal furnace cover is provided with an observation hole; the plurality of sight holes are arranged on the side of the refrigeration device main body opposite to the observationhole, so that it is convenient to observe single crystal growth. The beneficial effects are that: the plurality of sight holes are adopted, so that it is convenient for observation of single crystalgrowth; with a crystal crystallization region temperature ensured to be at a silicon crystallization point temperature, crystal surface heat energy loss is accelerated, crystal axial temperature gradient is increased, and single crystal pulling speed accelerating is promoted.

The invention discloses a single crystal furnace for achieving rapid crystal growth through a chemical heat sink enhanced cooling technology and mainly relates to a reaction device capable of conveying reactants and carrying out a chemical endothermic reaction inside the device. The reaction device is composed of a graphite cylinder and a reaction cylinder, wherein the reaction cylinder is made of an inert material; the reactants are introduced from an inlet, the chemical endothermic reaction is carried out in the reaction cylinder at a high temperature, the temperature on the surface of the reaction device and in a nearby argon gas area thereof is reduced, heat on the crystal surface is rapidly transferred, and incompletely reacted reactants and the reaction product are discharged out of the furnace by an outlet. The single crystal furnace is reasonable in structural design, the reactants can react in the reaction device, and impurities can be prevented from being introduced into the furnace in the reaction process. According to the device disclosed by the invention, the growing crystal is subjected to enhanced cooling by virtue of the chemical endothermic reaction, the heat on the crystal surface is rapidly transferred, and the axial temperature gradient inside the crystal is obviously improved, so that the crystal growth speed is improved, and the aim of reducing the crystal preparation cost is achieved.

The invention provides a crystal growth device and a crystal growth method. The growth device comprises a shell which defines a cavity and is provided with a first opening and a second opening which are oppositely arranged; a heat preservation layer is arranged on the inner wall of the shell; a crucible is surrounded by the heat preservation layer and is used for containing molten soup; a heater is arranged between the crucible and the heat preservation layer; a cooling sleeve is arranged below the first opening; a heat shield is arranged below the cooling sleeve and consists of a plurality ofmolybdenum sheets which are arranged in parallel; and a first micro heater is arranged below the heat shield and extends in the horizontal direction. According to the invention, heat energy loss on the crystal surface can be effectively prevented; compared with the prior art, the method has the advantages that the axial temperature gradient of the crystal is increased, the radial temperature gradient of the crystal can be reduced, the crystallization rate of the large-size crystal with the size of 12 inches or above is increased, the good time is maintained within the range of 1300-1400 DEG C, defects are fully discharged out of the crystal, and then the approximately perfect crystal is grown.