METHOD OF PRODUCING AB MONOCRYSTALS Russian patent published in 2010 - IPC C30B27/02 C30B29/40 

FIELD: chemistry.

SUBSTANCE: invention can be used in production of monocrystals of decomposable semiconductor compounds A³B⁵ via Czochralski method, particularly when growing monocrystals of phosphides of gallium and indium and gallium arsenide from under a boric anhydride layer. A³B⁵ monocrystals are obtained by drawing from melt to a nucleating agent under a boric anhydride layer which is loaded into a container, heated and melted. Molten boric anhydride is held for 0.5-3 hours at 900-1200°C with axial temperature gradient of 5-40°C/cm and addition of gallium in amount of 0.8-3.0 % of the weight of boric anhydride. Sullage is removed from the surface of the melt and volatile impurities are removed through ventilation. Vacuum pumping is then carried out for 0.5-20 hours at 950-1250°C. Boric anhydride is removed from the container and cooled. Addition of bismuth in amount of 0.01-0.5% of the weight of boric anhydride is proposed when melting boric anhydride together with gallium. Boric anhydride can be obtained by using boric acid, a portion of which is put into a container in amount of 10-20% of the load weight and dehydrated. Gallium is then added in amount of 0.4-1.5% of the weight of boric acid, after which the remaining portion of boric acid and molten boric anhydride is held for 0.5-2 hours before vacuum pumping. When removing boric anhydride from the container, all the gallium and a portion of boric anhydride in amount of 50-300% of the weight of the initial gallium can be left. Boric anhydride is then loaded again and the process is repeated. The obtained boric anhydride and A³B⁵ compound are loaded into a crucible and heated and a monocrystal is grown on a nucleating agent from the melt.

EFFECT: high output of suitable and improved quality of monocrystals for optical devices and production of ultra bright light-emitting diodes owing to lower content of impurities in the boric anhydride and molten A³B⁵ compound.

4 cl, 3 ex, 2 tbl