Growth device for sapphire crystal hemisphere cover and growth method for sapphire crystal hemisphere cover

Abstract

The invention relates to a growth device and a growth method for a sapphire crystal hemisphere cover by employing an edge-defined film-fed crystal growth method. The method specifically comprises the following main steps: respectively introducing a protective gas and a cooling gas into a crystal growth furnace and a cooler pan; heating the crystal growth furnace until a high-purity aluminum oxide material is fused; adjusting a hoist pan, so that aluminum oxide melt ascends to the top end of a mold along a center through hole and an annular capillary fissure in the symmetric axis of the mold; descending seed crystal to fuse with the aluminum oxide melt; under the action of affinity and surface tension, enhancing radiation heat exchange between a growth interface and the gas cooler pan by adjusting the flow of the cooling gas in the cooler pan, so as to quicken the expansion of the crystal; and finally limiting the expansion of the crystal by the top edge of the mold. The growth device has the advantages that supply of the melt in the mold is adjusted by controlling the relative positions of the mold and the crucible; continuous providing of the melt in the capillary fissure is ensured, so as to realize continuous growth; and a hexagonal annular cooler pan is prevented from being carbonized to deform by employing the cooling gas.

Description

technical field [0001] The invention belongs to the field of crystal growth, and relates to a sapphire crystal growth device and a growth method, in particular to a sapphire crystal dome cover growth device and a growth method thereof. Background technique [0002] There are many methods for the growth of sapphire crystal materials, mainly including: Kyropolous method (Ky method for short), guided mode method (Edge Defined Film-fed Growth techniques method, EFG method for short), heat exchange method ( That is, Heat Exchange Method (HEM method for short), pulling method (Czochralski method, Cz method for short), Bridgman method (Bridgman method, crucible drop method) and so on. [0003] The principle of the guided film method is to use the capillary slit on the mold to lift the raw material in the crucible to the top of the mold through capillary phenomenon. [0004] At present, in the process of growing sapphire crystals, relying on hard felt or metal screens placed near t...

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Problems solved by technology

[0005] (1) Only relying on thermal insulation felt or metal screen, or gas convection heat transfer, when the diameter of the crystal is larger or the thickness is thicker, the heat dissipation effect of the carbon felt or metal screen on the center of the growth interface rapidly decays, and the metal screen passes through After high-temperature deformation, it further causes uneven heat dissipation conditions at the crystal growth interface, making the shape of the growth interface uneven, resulting in many bubbles inside the crystal, and excessive cooling of the crystal aggravates the stress and dislocation problems of the crystal; at the same time, the growth interface Nearby carbon felt can cause carbon incorporation into the crystal, which can also affect crystal quality;

[0006] (2) The method of using the continuous movement of the seed crystal and mold phase position, but the moving seed crystal and mold cannot ensure that the growth interface is stably located on the symmetry axis of the thermal field, so the growth interface is easily deformed and unstable, while the relatively moving The growth interface further increases the difficulty of crystal quality control, and it is also difficult to continuously obtain large-diameter sapphire crystals due to the aforementioned factors

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