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

The invention discloses a vertical Bridgman growth furnace. From the bottom up, the inside of an outer shell of the furnace is provided with a thermal insulating board, two groups of I type heating modules, a cooling fin, a group of II type heating modules, two groups of I-type heating modules and a furnace hearth cover. The center hole of the thermal insulating board is filled with fireproof ceramic cotton, and the center of five sections of heating modules is provided with two sections of liner tubes which are separated by the cooling fin, and the outside of the joint of the liner tubes is provided with a liner sleeve, and the surrounding of the center hole of each group of heating modules is provided with an electric heated wire of each separate temperature control system, and a Pt / PtRh10 thermocouple is arranged in the radical direction, being in the middle of the outer wall which is vertical to the outer wall of each group of modules, and the temperature measuring contact of the thermocouple is close to the outer wall of the liner tube 5. The invention also discloses the optimization method of the temperature field of the vertical Bridgman growth furnace. As the vertical Bridgman growth furnace adopts the design of five sections of modules, adjustable temperature field for growing various crystals can be obtained by changing different modules, thus solving the problem of constitutional super cooling caused by small axial temperature gradient.

The invention discloses a micro-downward pulling crystal growth furnace, which comprises an upper heat insulation layer and a bottom heat insulation layer (13) arranged from top to bottom, and an observation hole (4) is arranged in the bottom heat insulation layer (13) for observation The hole (4) is tubular, and the included angle between its central axis and the normal to the top surface of the bottom insulation layer (13) is 45° to 60°; the inner layer insulation layer, the middle insulation layer and the bottom insulation layer (13) are all composed of mass Zirconia and alumina with a ratio of 1:9 are pressed and calcined. The observation window provided by the invention can observe the crystal growth condition at the crystal growth interface in time; moreover, the observation window has little influence on the temperature field of the crystal growth furnace, and can further improve the yield of crystal growth.

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 application discloses a silicon carbide single crystal, a substrate and a preparation method thereof, belonging to the field of semiconductor materials. The silicon carbide single crystal preparation method comprises that the temperature measuring hole formed by the upper insulation layer group outside the crucible forms a low-temperature zone and a high-temperature zone in the crucible, and the raw material in the high-temperature zone is gas-phase transported to the surface of the seed crystal in the low-temperature zone by using a physical gas phase transport method. Carry out crystal growth; the upper insulation layer group includes the second insulation layer and the first insulation layer arranged in sequence along the direction of the raw material from the seed crystal, the first insulation layer is provided with the first opening, the second insulation layer is provided with the second opening, and the rotation adjustment mechanism Rotate the first insulation layer and / or the second insulation layer to adjust the cross-sectional area of ​​the temperature measuring hole formed by the first opening and the second opening, thereby adjusting the axial and radial temperature gradients in the crucible during the crystal growth process. The silicon carbide single crystal preparation method can not only adjust the radial temperature gradient in the growth chamber for growing single crystals; but also ensure a certain axial temperature gradient while reducing the radial temperature gradient, and produce high-quality silicon carbide single crystals with high efficiency. crystal.

The present application discloses a high-quality silicon carbide crystal and a growth method and device thereof, which include the following steps: 1) assembling: after installing a seed crystal unit in a crucible filled with raw materials, move it into a closed accommodating cavity; 2) long Crystal stage: control the crystal growth conditions in the accommodating cavity, adjust the temperature of the first cooling water to 8-16 ℃, and the flow rate to 18-54 mL / s, that is, to obtain the crystal; wherein, the accommodating cavity is composed of An assembly of cooling jackets is formed, the cooling jackets include a first cooling pipe and a second cooling pipe, the first cooling pipe being sleeved inside the second cooling pipe and cooperating to form a connection for passage into the second cooling pipe. A first interlayer of cooling water, the thickness of the first interlayer linearly increases along the direction from the bottom of the crucible to the opening. The crystal growth method can realize the controllable axial temperature gradient inside the crucible, thereby controlling the growth quality and growth rate of the crystal; at the same time, the axial temperature gradient formed in the crucible is more stable, which can further ensure the crystal growth quality.