Patent ID: 6869477

Claim:
A process for eliminating dislocations in a neck of a single crystal silicon ingot, grown in accordance with the Czochralski method, the process comprising: heating polycrystalline silicon in a crucible to form a silicon melt; contacting a seed crystal to the melt until the seed begins to melt, forming dislocations therein; withdrawing the seed crystal from the melt at a growth rate R 1 to form a first segment of a neck having a diameter of at least about 5 mm; decreasing the growth rate R 1 to a growth rate R 2 to form a second segment of a neck having a diameter of at least about 5 mm; and, increasing the growth rate R 2 to a growth rate R 3 to form an additional segment of a neck having a diameter of at least about 5 mm; wherein the growth rate R 2 is at least about 25% less than the growth rate R 1 , wherein the neck has a substantially constant diameter, and wherein dislocations are eliminated in the neck within an axial length of less than about 150 mm.