DEVICE FOR GROWING SAPPHIRE MONO-CRYSTALS Russian patent published in 2004 - IPC

FIELD: growing body-centered sapphire mono-crystals from melt. SUBSTANCE: proposed device includes th following components mounted in vacuum chamber: heater, crucible with mold, seed holder, thermal shields, control systems for raising seed crystal and heater power; mounted coaxially in crucible is tungsten insert made in form of bowl copying the shape of crucible or in form of set of rings made from tungsten bars vertically and horizontally; rings mounted vertically are fitted coaxially on another and rings mounted horizontally are placed concentrically relative to one another. Besides that, basket is placed between bowl-shaped insert and crucible; baskets are made in form of 1-3 pairs of bent tungsten bars fastened together at lower point; their ends project above upper edge of crucible and are bent outside; basket is made from tungsten bars, 2-3 mm in diameter; thickness of walls of bowl- shaped insert ranges from 300 to 500 mcm; crucible is made from molybdenum-and-tungsten alloy; rings of insert are fastened together and upper ring is provided with holders. EFFECT: increased service life of components. 7 cl, 3 dwg, 2 x