Devices and methods for growing crystals

Abstract

The present disclosure provides a method for growing a seed crystal, including: obtaining a plurality of orthohexagonal seed crystals in a hexagonal crystal system by performing a first cutting on a plurality of seed crystals in the hexagonal crystal system to be expanded, respectively; splicing the plurality of orthohexagonal seed crystals in the hexagonal crystal system; obtaining a seed crystal in the hexagonal crystal system to be grown by performing a second cutting on the plurality of spliced orthohexagonal seed crystals in the hexagonal crystal system; obtaining an intermediate seed crystal in the hexagonal crystal system by performing a gap growth on the seed crystal in the hexagonal crystal system to be grown under a first setting condition; and obtaining a target seed crystal in the hexagonal crystal system by performing an epitaxial growth on the intermediate seed crystal in the hexagonal crystal system under a second setting condition.

What is claimed is: 
     
         1 . A method for growing a seed crystal, comprising:
 obtaining a plurality of orthohexagonal seed crystals in a hexagonal crystal system by performing a first cutting on a plurality of seed crystals in the hexagonal crystal system to be expanded, respectively, wherein cutting faces of the plurality of orthohexagonal seed crystals correspond to a same lattice plane family;   splicing the plurality of orthohexagonal seed crystals in the hexagonal crystal system;   obtaining a seed crystal in the hexagonal crystal system to be grown by performing a second cutting on the plurality of spliced orthohexagonal seed crystals in the hexagonal crystal system;   obtaining an intermediate seed crystal in the hexagonal crystal system by performing a gap growth on the seed crystal in the hexagonal crystal system to be grown under a first setting condition; and   obtaining a target seed crystal in the hexagonal crystal system by performing an epitaxial growth on the intermediate seed crystal in the hexagonal crystal system under a second setting condition, wherein
 a diameter of the target seed crystal in the hexagonal crystal system is larger than a diameter of the seed crystals in the hexagonal crystal system to be expanded. 
   
     
     
         2 . The method of  claim 1 , wherein a cutting direction of the first cutting is a direction perpendicular to a surface (0001) of the plurality of seed crystals. 
     
     
         3 . The method of  claim 1 , wherein the lattice plane family is {11 2 0} or {1 1 00}. 
     
     
         4 . The method of  claim 1 , wherein the splicing the plurality of orthohexagonal seed crystals in the hexagonal crystal system includes:
 taking one of the plurality of orthohexagonal seed crystals in the hexagonal crystal system as a center, tightly splicing each of six sides of the central orthohexagonal seed crystal in the hexagonal crystal system with one side of six orthohexagonal seed crystals in the hexagonal crystal system.   
     
     
         5 . The method of  claim 4 , wherein the performing a second cutting on the plurality of spliced orthohexagonal seed crystals in the hexagonal crystal system includes:
 performing the second cutting by taking a center point of the central orthohexagonal seed crystal in the hexagonal crystal system as a center and a setting radius as a radius.   
     
     
         6 . The method of  claim 4 , wherein a surface area of the central orthohexagonal seed crystal in the hexagonal crystal system is larger than surface areas of orthohexagonal seed crystal in the hexagonal crystal system located in other positions. 
     
     
         7 . The method of  claim 4 , wherein a surface area of the central orthohexagonal seed crystal in the hexagonal crystal system is within a range of 25% to 55% of a surface area of the target seed crystal in the hexagonal crystal system. 
     
     
         8 . The method of  claim 1 , wherein the first setting condition includes a first setting temperature, a first setting pressure, a first setting carbon-silicon ratio, and a setting gap growth time, wherein the first setting temperature is within a range of 1000° C. to 2000° C., the first setting pressure is within a range of 10 Pa to 1000 Pa, and the first setting carbon-silicon ratio is within a range of 1.0 to 10.0. 
     
     
         9 . The method of  claim 1 , wherein the second setting condition includes a second setting temperature, a second setting pressure, a second setting carbon-silicon ratio, and a second gap growth time, wherein
 the second setting temperature is within a range of 1100° C. to 2000° C.,   the second setting pressure is within a range of 10 Pa to 1000 Pa, and   the second setting carbon-silicon ratio is within a range of 0.1 to 2.   
     
     
         10 . The method of  claim 1 , wherein the second cutting includes a grinding operation by a bias shaft. 
     
     
         11 . The method of  claim 10 , wherein a direction of the grinding operation by the bias shaft is [0001] deflecting 3 degrees to 6 degrees pointing to the direction of the [11  2 0]. 
     
     
         12 . The method of  claim 1 , wherein the method further includes:
 before preforming the gap growth, performing an in-situ etching operation on the seed crystal in the hexagonal crystal system to be grown under a third setting condition to improve a surface flatness of the seed crystal in the hexagonal crystal system to be grown.   
     
     
         13 . The method of  claim 12 , wherein the third setting condition includes a setting gas with a preset flow rate, a third setting temperature, and a third setting pressure, wherein
 the setting gas includes hydrogen and the setting flow rate is within a range of 5 liters per minute to 200 liters per minute,   the third setting temperature is within a range of 1200° C. to 1500° C., and   the third setting pressure is within a range of 1 KPa to 12 KPa.   
     
     
         14 . The method of  claim 12 , wherein the in-situ etching operation is performed in a chemical vapor deposition device, and the method further includes:
 before performing the in-situ etching operation, performing a pre-treatment on the chemical vapor deposition device, wherein the pre-treatment includes at least one of a vacuum operation or a heating operation.   
     
     
         15 . The method of  claim 1 , wherein the method further includes:
 before preforming the first cutting, performing a polishing operation on the plurality of seed crystals in the hexagonal crystal system to be expanded, respectively.   
     
     
         16 . The method of  claim 1 , wherein the seed crystal in the hexagonal crystal system includes 4H—SiC or 6H—SiC. 
     
     
         17 . The method of  claim 1 , wherein a thickness of the target seed crystal in the hexagonal crystal system is within a range of 400 microns to 700 microns. 
     
     
         18 . The method of  claim 1 , wherein the diameter of the target seed crystal in the hexagonal crystal system is not less than twice the diameter of the seed crystals in the hexagonal crystal system to be expanded. 
     
     
         19 . The method of  claim 1 , wherein the diameter of the target seed crystal in the hexagonal crystal system is larger than 8 inches. 
     
     
         20 . The method of  claim 1 , wherein the diameter of the target seed crystal in the hexagonal crystal system includes 8 inches, 9 inches, or 10 inches.