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US 2003/0079673 A1Published application
Seed crystals for pulling single crystal silicon
AssigneeMEMC Electronic Materials, Inc.
InventorsHariprasad Sreedharamurthy, Mohsen Banan
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Abstract
The present invention provides for a process for preparing a single crystal silicon ingot by the Czochralski method. The process comprises selecting a seed crystal for Czochralski growth wherein the seed crystal comprises vacancy dominated single crystal silicon.
Claims14
A process for preparing 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;
- selecting a seed crystal for contacting the crystal melt, said seed crystal having crystal lattice vacancies as the predominant intrinsic point defect therein;
- contacting said seed crystal to the silicon melt until the seed crystal begins to melt, forming dislocations therein;
- withdrawing the seed crystal from the melt to grow a neck portion of the ingot, wherein during the withdrawal dislocations are eliminated from the neck;
- growing an outwardly flaring seed-cone adjacent the neck portion of the ingot;
- and,
- growing a main body adjacent the outwardly flaring seed-cone, the body having a nominal diameter of at least about 150 mm.
4 more elements
Dependencies are inferred from the claim text.