Improved device and method for growing high-temperature oxide crystals through heat exchange method with seed crystals arranged on top

Abstract

The invention discloses a device and a method for growing a high-temperature oxide crystal by an improved heat exchange method with a seed crystal arranged on the top, which are characterized in that a kyropoulos method, a Czochralski method (CZ), a heat exchange method (HEM), a temperature gradient method (TGT), a Bridgman-Stockbarger method and a kyropoulos method (KY method) are combined together; according to the special high-temperature vacuum crystal furnace, gas flows in from the center of the top of a hearth from top to bottom, absolute uniform and symmetrical flow out from the center of the bottom is ensured through flow planning, and gradients of all parts in different growth stages are achieved by adjusting the gas flow in different stages and the pumping speed of a vacuum pump. The method comprises the following steps: charging a furnace, vacuumizing, introducing flowing protective gas, heating and melting materials, washing seed crystals, changing the gas inlet and outlet proportion, carrying out real-time gradient adjustment, seeding by a pulling method, carrying out a hole shrinkage process, increasing the shouldering process of a heat exchange method for increasing the gas flow, controlling a crystal growth interface (adjusting a convex interface to be slightly convex or close to a flat interface), and carrying out equal-diameter growth by combining HEM heat exchange with a KY technology (namely carrying out equal-diameter growth by combining HEM heat exchange with a KY technology). A weighing diameter control technology is optimized; amp is ended through a KY method; and removing the crucible, and performing in-situ annealing by gradually increasing the pressure of the protective gas. According to the invention, the existing method is combined to produce the large-size high-temperature oxide crystal.

Description

technical field [0001] The invention relates to the technical field of high-temperature oxide crystal growth, in particular to a device and method for growing high-temperature oxide crystals by an improved heat exchange method with a seed crystal on top. Background technique [0002] At present, there are five commonly used methods for growing high temperature oxide crystals: pulling method, heat exchange method, crucible descent method, temperature gradient method and Kyropoulos method. The disadvantages of the pulling method are: 1. Under the same crucible conditions, the crystals are small, and the diameter does not exceed 50% of the crucible. 2. Due to the large gradient, the growth interface is excessively raised, the thermal stress is large, and the dislocation value increase causes dislocations. If the density is too large, the single crystal property is not good; 3. The temperature gradient is large and the energy consumption is high. The disadvantages of the heat e...

AI Technical Summary

Problems solved by technology

The disadvantages of the pulling method are: 1. Under the same crucible conditions, the crystals are small, and the diameter does not exceed 50% of the crucible. 2. Due to the large gradient, the growth interface is excessively raised, the thermal stress is large, and the dislocation value increase causes dislocations. If the density is too high, the single crystal property is not good; 3. The temperature gradient is large and the energy consumption is high

The disadvantages of the heat exchange method are: high requirements on equipment conditions, complex process, long crystal growth period, large amount of helium as coolant, high cost, temperature gradient distribution is opposite to the gravity field, which is not conducive to impurity removal, and the crystal is in contact with the crucible. The stress of the crystal is large, and it is easy to cause polycrystals due to parasitic nucleation. The crystal growth cannot be controlled and observed in real time, and the growth interface is too convex, and the thermal stress and dislocation are large.

The disadvantages of the crucible drop method are: it is not suitable for materials with a negative expansion coefficient, and materials with a liquid density greater than that of a solid. Due to the action of the crucible, it is easy to form stress, parasitic nucleation and pollution, and it is not easy to observe and there is mechanical disturbance in the falling mechanism; Disadvantages of the gradient method The temperature gradient distribution is opposite to the gravity field, which is not conducive to impurity removal. The crystal is in contact with the crucible, the stress of the crystal is large, and it is easy to cause polycrystals due to parasitic nucleation. The crystal growth cannot be controlled and observed in real time and the growth interface is too convex. Stress and bit misses are large

Each of the existing crystal growth methods has more or less certain problems, and no method can actively control the crystal growth interface according to the different stages of crystal growth.

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