FIELD: technological processes.
SUBSTANCE: method includes growing alloyed single crystals of germanium from melt in crucible to crystallographically oriented priming powder, with diameter that is equal to internal diameter of crucible, under conditions of thermal axial flow next to crystallisation front - by OTF method, with application of background heater and double-section heater immersed in melt (OTF-heater) by means of displacement of crucible with priming powder and growing crystal in cold zone of furnace in respect to OTF-heater, which is maintained at constant temperature, with presence of different initial concentrations of alloying admixtures C1 and C2 in melt zones W1 and W2, with thickness of melt layer h in zone W1. Control of crystallisation front shape is carried out simultaneously by OTF- and background heaters, at that in the process of crystal pulling crucible bottom temperature T4(t) is reduced according to the following law: T4(t)=T4 0-axt, where T4 0 - initial value of temperature, a=v(λr×gradTp+Q)/λcr, v - rate of crystal pulling, λr - heat conductivity of germanium melt, gradTp - axial gradient of temperature in melt, at which crystal is grown, Q - crystallisation heat, λcr - heat conductivity of germanium crystal, value h is selected from the condition h<0.3D, where D - diameter of OTF- heater, and ratio of initial concentrations C1 and C2, accordingly, in zones W1 and W2 satisfies condition C1-C2/K, where K - equilibrium coefficient of segregation for used alloying admixture. Method permits to produce alloyed single crystals of germanium with diameter of up to 76 mm without growth strips with high transverse macro-homogeneity of resistance distribution: 1.5-2.5%.
EFFECT: production of single crystals with improved characteristics.
5 cl, 1 ex, 2 dwg
