METHOD AND APPARATUS FOR GROWING OF MONOCRYSTALS FROM HIGH-MELTING POINT MATERIALS Russian patent published in 1995 - IPC

FIELD: inorganic chemistry. SUBSTANCE: method involves heating the whole volume of burden to premelting temperature; holding heated burden till temperature of the whole volume of burden is stabilized; providing through melting by successive advancement of overheated melt zone, beginning from cradle end opposed to seed, in the direction of seed till a portion of it is molten; conducting crystallization process in reverse order, that is, by successive advancement of melt zone from seed, with temperature of crystallized part of material being maintained not below temperature, at which material transforms to elastical deformation state; cooling crystal to normal temperature with isothermic conditions through the whole volume being maintained. Burden is heated to premelting temperature not exceeding 0.95 of burden melting temperature. Melt zone temperature is 1.1 of melting temperature. Apparatus has coiled heater with independent sections, each containing odd number of coils having various sections, with maximum section portion positioned in the middle of heater. Coils are positioned at an angle with respect to longitudinal axis of container. Additional heat shields are mounted in each section below container. Heat insulating enclosure positioned above and below container has variable section and maximum thickness in the vicinity of coil portions having maximum section. EFFECT: increased efficiency and high quality of monocrystals. 3 cl, 4 dwg