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US 5,954,873 AGranted
Manufacturing method for a silicon single crystal wafer
AssigneeSumitomo Sitix Corporation
InventorsMasataka Hourai, Eiji Kajita
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Abstract
A method of making silicon single crystal wafers free of grown-in defects is provided. These wafers are formed from silicon single crystal manufactured by the Czochralski method. Careful control of the pulling rate, V (mm/min), and the temperature gradient G (.degree. C./mm) permits crystals to be formed that are free from OSF rings, and other types of defects.
Claims9
A method of making a silicon single crystal comprising:
- pulling said single crystal at a pulling rate V and at a temperature gradient G,
- wherein the ratio of said pulling rate to said temperature gradient, V/G, is 0.20-0.22 mm.sup.2 /.degree. C.min in an first region, and greater than 0.20 mm.sup.2 /.degree. C.min in a second region,
- wherein said single crystal comprises a center and an outer zone, and
- said first region is defined between said center and a outer boundary and said second region is defined between said outer boundary and said outer zone.
1 more element
Dependencies are inferred from the claim text.