Dislocation-Free Czochralski Silicon Crystal Growth without Dash Necking

Abstract

Dislocation-free silicon crystals which underwent boron and phosphorus doping were grown by the Czochralski (CZ) method without Dash necking. The boron concentration limit in a silicon seed 7×7 mm2 in cross section without dislocations due to thermal shock was 1×1018 atoms/cm3 in ordinary CZ silicon-crystal growth. The maximum admissible discrepancy of boron concentration in the seed and grown crystal was 7×1018 atoms/cm3 without dislocations due to lattice misfit in the grown crystal. Silicon seeds with a boron concentration of 3×1018 atoms/cm3 were used to grow CZ silicon crystals from lightly boron-doped (p-type) or phosphorus-doped (n-type) silicon melt, yielding dislocation-free silicon crystals without the need for Dash necking. Heavily boron-doped silicon seed should thus be applicable in growing other practical lightly doped dislocation-free CZ-silicon crystals without the need for Dash necking.