Dopant transport during semiconductor crystal growth: Axial versus transverse magnetic fields

Abstract

The present study investigates the effects of magnetic field orientation, magnetic field strength and growth rate on the dopant segregation in semiconductor crystals, and presents results of dopant composition in the crystal and in the melt at several different times during growth for several combinations of process parameters. The crystal's lateral segregation depends on the magnetic field's orientation and strength while the axial segregation depends on the magnetic field's strength and the growth rate. If either convective or diffusive transport truly dominates, then the crystal's dopant distribution is laterally uniform. The axial distribution in the crystal approaches the well-mixed limit if the melt motion is strong and the growth rate is slow, and the distribution approaches the diffusion-controlled limit if the melt motion is slow and the growth rate is fast. The deviations of the dopant distribution in the crystal from lateral uniformity and from the classical limits are quantified for several combinations of process parameters.