Heavily Boron-Doped Silicon Single Crystal Growth: Constitutional Supercooling

Abstract

Constitutional supercooling in the heavily boron-doped Czochralski (CZ) silicon crystal growth has been investigated. It was found that cellular growth occurred first in the center of the crystal. The cellular growth changed gradually to facet growth and finally became polycrystalline growth. This process is quite different from the well-known mechanism of polycrystallization in the silicon crystal growth. The cellular growth occurred when the boron concentration in the crystal was approximately 3×10 20 atoms/cm 3 with the growth rate of about 1 mm/min. In the theoretical analysis using an equation for occurrence of the constitutional supercooling, it is found that the condition for the occurrence is satisfied by considering that the segregation coefficient of boron decreases with increasing boron concentration in the heavily boron-doped silicon crystal growth.