Macroscopic Axial Dopant Distribution in Czochralski Silicon Crystals Grown in a Vertical Magnetic Field

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Abstract
Phosphorus and aluminum-doped silicon crystals 3 inches in diameter are grown by the Czochralski method in a vertical magnetic field of 2500 Oe. It is shown that the macroscopic axial dopant distribution is remarkably homogenized by the magnetic field. Melt stirring under the magnetic field is apparently only partial, and the effective segregation coefficients for phosphorus and aluminum are 0.77 and 0.0082, respectively, several times larger than the respective equilibrium values. The diffusion layer thickness is accurately determined to be as thick as 5 ∼6 mm in the strong vertical magnetic field, confirming our previous result obtained by microscopic analysis. Transients are found in the dopant concentration near the seed end of the crystal, giving strong evidence for a thick diffusion layer.