METHOD FOR GROWING SINGLE CRYSTALS OF PROFILED RADIAL GERMANIUM Russian patent published in 2017 - IPC C30B15/34 C30B29/08 G02B1/02 G02B13/14 

FIELD: metallurgy.

SUBSTANCE: method includes placing in a crucible a vertical form-builder with holes in area where its lower part adjoins the crucible for removal of excessive melt formed during crystallisation, placing horizontal forming elements of convex-concave shape in grooves of the vertical form-builder, loading initial charge into the vertical form-builder, heating thereof with formation of melt, immersion of seed crystal into the melt, growing crystal by reducing temperature at simultaneous drawing, stopping vertical drawing of crystal and further growing of crystal up to complete melt crystallisation, wherein increase of crystal in radius from moment of drawing stopping to full melt crystallisation is carried out by means of total temperature reduction, simultaneously performing melting and flattening the crystal caused by temperature increase and decrease with amplitude ±3°C for a period of 20 minutes. This growth mode leads to reduction in concentrations of structure major defects and associated optical inhomogeneities and physically equivalent to further annealing during crystal formation.

EFFECT: enhanced structural and optical quality of large-sized single crystals in the form of a blank, maximally close to the shape of manufactured lenses and other optical elements, acoustic-optical and photoelectric devices based on germanium.

3 dwg, 2 ex