Process for eliminating dislocations in the neck of a silicon single crystal
AssigneeMEMC Electronic Materials, Inc.
InventorsSadasivam Chandrasekhar, Kyong-Min Kim
Life of this patent
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Abstract
A silicon single crystal prepared by the Czochralski method including a neck having an upper portion, an intermediate portion, and a lower portion. The upper portion contains dislocations. The intermediate portion is between the upper and lower portions. A majority of the intermediate and lower portions has a diameter greater than 10 millimeters, and the lower portion is free of dislocations. The crystal also includes an outwardly flaring segment adjacent the lower portion of the neck, and a body adjacent the outwardly flaring segment.
Claims23
A process for eliminating dislocations in the neck of a silicon single crystal grown by the Czochralski method, the process comprising:
- contacting a seed crystal with a silicon melt until the seed crystal begins to melt and dislocations form in the seed crystal;
- withdrawing the seed crystal from the melt to form a neck comprising an upper portion and an intermediate portion, the upper portion being between the seed crystal and the intermediate portion and containing dislocations, a majority of the intermediate portion having a diameter greater than 10 millimeters;
- and
- growing the neck at a rate less than about 4.0 mm/min until the dislocations within the intermediate portion of the neck are eliminated.
A process for eliminating dislocations in the neck of a silicon single crystal grown by the Czochralski method, the process comprising:
- contacting a seed crystal with a silicon melt until the seed crystal begins to melt and dislocations form in the seed crystal;
- withdrawing the seed crystal from the melt to form a neck comprising an upper portion and an intermediate portion, the upper portion containing dislocations and being between the seed crystal and the intermediate portion, with the majority of the intermediate portion having a diameter greater than 10 millimeters and no portion of the intermediate portion having a diameter less than 8.5 millimeters;
- and
- growing the neck at a rate less than about 4.0 mm/min until the dislocations within the intermediate portion of the neck are eliminated.
A process for eliminating dislocations in the neck of a silicon single crystal grown by the Czochralski method, the process comprising:
- contacting a seed crystal with a melt of p.sup.+ -type silicon until the seed crystal begins to melt and dislocations form in the seed crystal;
- withdrawing the seed crystal from the melt to form a neck comprising an upper portion and an intermediate portion, the upper portion containing dislocations and being between the seed crystal and the intermediate portion, with the majority of the intermediate portion having a diameter greater than 10 millimeters;
- and
- growing the neck at a rate less than about 4.0 mm/min until the dislocations within the intermediate portion of the neck are eliminated.
Dependencies are inferred from the claim text.