Dislocation-Free Czochralski Si Crystal Growth without Dash Necking Using a Heavily B and Ge Codoped Si Seed

Dislocation-free Czochralski Si crystals were grown from undoped Si melt without Dash necking using heavily B and Ge codoped Si seeds 15×15 mm2 in cross-section. The concentration of B in codoped Si seeds was 2×1019 atoms/cm3 and that of Ge 8×1019 atoms/cm3. Dislocations due to thermal shock did not form in heavily B-doped seeds nor due to lattice misfit in grown crystals despite the very different B concentration in seeds and grown crystals. This indicates that B and Ge codoping adjusted the lattice constant of Si seeds to that of grown crystals.