PROCEDURE FOR GROWING MONO-CRYSTALS WITH SPECIFIED DISTRIBUTION OF ADDITIVES ALONG ITS WHOLE LENGTH Russian patent published in 2010 - IPC C30B15/20 C30B15/02 C30B15/12 

FIELD: metallurgy.

SUBSTANCE: procedure consists in pulling mono-crystal 10 from melt 13 with specified concentration of basic components in crucible-reactor 15, equipped with orifice or orifices 14 and installed inside main crucible 1, in transfer of crucible-reactor 15 relative to main crucible 1, and in control over their speed of transfer and over change of crystal weight by means of computer 3. At pulling crystal 10 composition of basic components of melt in crucible-reactor 15 and main crucible 1 is controlled by means of comparing the composition, corresponding to temperature registered with thermocouple 11 brought to the crystallisation front of growing crystal 10 and transferred together with crystal 10 in crucible-reactor 15, to the composition of melt corresponding to temperature registered with thermocouple 11 at a moment corresponding to a sharp surge in indications on the curve of change in weight of crystal on weight sensor 7 of growing crystal 10 in crucible-reactor 15. Further, the composition of melt in crucible-reactor 15 is compared to a theoretical composition of melt on phase diagram of condition of basic components. In case of agreement between the determined and theoretical compositions, crystal 10 is pulled at rate V_cr, while crucible-reactor 15 is transferred at rate calculated by formula: where is linear rate of crucible-reactor transfer relative to the main crucible; µ is parametre of replenishment; V₁ is weight rate of melt coming from the main crucible into the crucible-reactor, V_cr is weight rate of crystal pulling; S_o is area of cross section of the main crucible; ρ is density of melt. In case of disagreement between the determined and theoretically calculated compositions of melt in basic components in crucible-reactor 15, there is calculated deficit of weight of the main component, which is added to crucible-reactor 15. Further, there is carried out temperature control and the procedure is repeated to complete agreement of the determined and theoretically calculated composition of melt.

EFFECT: production of crystals with specified composition of main components and with intentionally determined concentration profiles by length of mono-crystal of one or several components of additives.

2 cl, 5 ex, 5 dwg