METHOD OF GROWING GERMANIUM MONOCRYSTALS WITH DIAMETRE OF UP TO 150 mm USING OTF METHOD Russian patent published in 2010 - IPC C30B13/18 C30B13/28 C30B13/10 C30B13/34 C30B29/08 

FIELD: physics.

SUBSTANCE: invention relates to growing doped germanium monocrystals in a temperature gradient using a heating element immersed in a melt under conditions of an axial heat flow near a crystallisation front (OTF method). The doped germanium monocrystals are grown from a melt in a crucible placed on a heat-removing unit to an crystallographically directed innculant with diametre equal to the inner diametre of the crucible, under conditions of axial heat flow near the crystallisation front - OTF method, using a multi-section background heater and a multi-section immersed in the melt - OTF-heater kept at constant temperature T₁ by moving the crucible with the inoculant and growing crystal into the cold zone of the furnace relative the OTF-heater, with different initial concentrations of doping impurities C₁ in the crystallisation zone W₁ with height of the melt h, and C₂ in a replenishment zone W₂, and with reduction of temperature of the bottom of the crucible T₄(t) when moving, in accordance with the law: T₄(t)=T₄ ⁰ -a×t, where T₄ ⁰ is initial temperature value, a=v(λ_m×gradTp+Q)/λ_cr, v is drawing rate of the crystal, λ_m is thermal conductivity of molten germanium, gradTp is axial temperature gradient in the melt in which the crystal is grown, Q is crystallisation heat, λ_cr is thermal conductivity of the germanium crystal. Mass transfer of the melt is controlled in the crystallisation zone by selecting optimum ratio between axial temperature gradient in the melt gradTp, radial distribution of temperature along the OTF-heater, height of the layer of the melt h and drawing rate v. Germanium monocrystals are grown in crystallographic dirctions [111] and [100] depending on diametre of the crystal and required quality given the following parameters: h=5-30 mm, gradTp=3-50°C/cm, v=2-30 mm/h, temperature difference of the OTF-heater T₂-T₁=0-6°C, temperature difference between the lateral surface of the crucible T₃ and temperature of the OTF-heater T₂, equal to T₃-T₂=1-20°C.

EFFECT: obtaining germanium monocrystals with diametre of up to 150 mm without growth region with high cross sectional macro-uniformity of distribution of resistance of 5-10%.

10 cl, 1 ex, 2 dwg