Control of oxygen-atom transport in silicon melt during crystal growth by electromagnetic force

A novel method for the control of oxygen-atoms transport in silicon melt du ring crystal growth, using an electromagnetic force (EMF) to rotate the mel t without crucible rotation, has been developed. We have named this techniq ue, the electromagnetic Czochralski (EMCZ) method. An EMF in the azimuthal direction is generated in the melt by the interaction between an electric c urrent (I) through the melt in the radial direction and a vertical magnetic field (B). The effectiveness of this method was confirmed by numerical sim ulation based on the finite element method. The rotation rate (omega(m)) of the silicon melt is continuously changed from 0 to over 105 rpm under I = 0 to 8 A and B = 0 to 0.1 T. Thirty-mm-diameter silicon single crystals fre e of dislocations could be grown under several conditions. The oxygen conce ntration in the crystals was continuously changed from 1.1 x 10(-3) to 11.4 x 10(-3) mass% (1 x 10(17) to 1 x 10(18) atoms/cm(3)) by applying an elect romagnetic force in order to increase the melt rotation. Homogeneous oxygen distributions in the radial directions were achieved. The continuous chang e in oxygen concentration and the homogenization of the oxygen distribution along the radial direction are attributed to the control of the diffusion- boundary-layer at both the melt/crucible and crystal/melt interface by forc ed how caused by the EMF. This new method could be useful for the growth of the large-diameter silicon crystals with a homogeneous distribution of oxy gen.