DEVICE FOR GROWING PROFILED SAPPHIRE MONOCRYSTALS Russian patent published in 2007 - IPC C30B15/34 C30B29/20 

FIELD: growing monocrystals of refractory oxides from melts by oriented crystallization; production of sapphire monocrystals corresponding to opto-electronics requirements.

SUBSTANCE: proposed device has vacuum chamber with crucible and molding unit, tungsten heater, shields, rod with seed holder which is provided with crystal raising mechanism mounted outside the chamber, melt make-up system made in form of bin with tube and unit for control of heating and rate of raising the crystal. Device is additionally provided with annealing vacuum chamber mounted above chamber with crucible and molding unit coaxially relative to it and system for synchronization of mass of crystal being grown and consumption of make-up material; annealing vacuum chamber is provided with self-contained heater whose height is equal to or exceeds maximum size of length of crystal obtained; diameter of annealing chamber ranges from 0.6 to 0.9 of diameter of lower chamber; mounted in between chambers is partition with holes for rod with seed holder, crystal being grown and make-up; molding unit is made in form of parallelepiped with parallel through vertical slots which is mounted in crucible at clearance and is secured on crucible walls; height of parallelepiped is equal to 20-30% of crucible height; width of slots is 0.2-0.3 mm at distance between them of 0.2-0.5 mm; in horizontal plane ends of slots are blind. Proposed device makes it possible to eliminate voids lesser than 50 mcm in diameter at obtaining the crystals whose transversal size is lesser than 100 mm at crystallographic orientation of <1010> or <1120>. Power requirements are reduced by 4-6 times. Monocrystals grown with the aid of this device have low internal stresses which is important for further mechanical treatment of crystals.

EFFECT: reduced power requirements; low internal stresses of crystals.

7 cl, 2 dwg