CZOCHRALSKI'S METHOD OF GROWING PARATELLURITE MONOCRYSTALS FROM LIQUID MELT Russian patent published in 2017 - IPC C30B15/00 C30B15/20 C30B29/16 

FIELD: chemistry.

SUBSTANCE: growing is carried out from a fixed crucible with programming the seeding pulling and rotation speeds, wherein, after reaching the desired diameter, pulling the cylindrical part is conducted at rotation speeds the values of which correspond to Reynolds numbers 100-150. In said mode, a system of two opposite convective supercooled melt cells orbiting the crystal, of a darker colour than the rest of the surface, is formed on the melt surface. Thereinafter, with a period of 600-800, the reversible rotation direction of the seeding with the crystal is changed to the contrary during the entire pulling time. The uniform rotation speed reduction, the rotation direction switching, as well as the uniform increase in the rotation speed to the previous absolute value, are carried out for a time of 200-240 c. Reversive rotation results in periodic destruction of the melt stagnation area under the central - paraxial - part of the growing crystal surface, which provides a more uniform distribution of impurities and other structural defects along the crystal radius.

EFFECT: improved structural perfection and uniformity of paratellurite single crystals and the elements of optical and acousto-optic devices made thereof.

2 dwg, 2 ex