SINGLE CRYSTAL GROWING METHOD CONTROLLING COVECTION CURRENT FIELD IN MELT

摘要

PURPOSE: To obtain a Si single crystal having uniformized impurity concentration distribution in a growing direction by a Czochralski method. CONSTITUTION: In pulling up a single crystal from melt, the temperature differentΔT is controlled so as a Rayleigh number Ra defined as Ra=(g.β.ΔT.L)/(κ.ν) to be in a range of 5×10<5> -4×10<7> wherein (g) is an acceleration of gravity, (β) is a coefficient of volume expansion,ΔT is a temperature difference between bottom face of a crucible and growth interface, L is depth of the melt, (κ) is heat diffusivity and (ν) is coefficient of kinematic viscosity. By the process, a convection current mode of the melt at the growth interface is always kept in a soft turbulent flow region and a single crystal is grown under a stable temperature condition without taking in an impurity contamination in the melt.