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 wi thout Dash necking using heavily B and Ge codoped Si seeds 15 x 15 mm(2) in cross-section. The concentration of B in codoped Si seeds was 2 x 10(19) a toms/cm(3) and that of Ge 8 x 10(19) atoms/cm3. Dislocations due to thermal shock did not form in heavily B-doped seeds nor due to lattice misfit in g rown crystals despite the very different B concentration in seeds and grown crystals. This indicates that B and Ge codoping adjusted the lattice const ant of Si seeds to that of grown crystals.