Method for manufacturing single-crystal silicon
AssigneeSiltronic AG
InventorsHideo Kato, Shinichi Kyufu, Masamichi Ohkubo
Life of this patent
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Abstract
Single crystal silicon ingots are grown by the multi-pulling method in a single crucible with minimization of dislocations by incorporating barium as a quartz crystallization inhibitor in amounts proportional to the diameter of the Czochralski crucible in which the crystal is grown. In at least one of the crystal pulling steps, a magnetic field is applied.
Claims8
A method for manufacturing single-crystal silicon using a multi-pulling method for pulling up a plurality of pieces of single-crystal silicon from a material melt in an identical crucible within a chamber by a Czochralski method, the method comprising the steps of:
- preparing said material melt in said crucible, wherein the crucible has a diameter of 24 inches or more, and a layer containing barium is formed on an inner wall of the crucible in an amount related to the diameter of the crucible such that the amount of barium is about 2.2×1014 atoms·cm−2 for a crucible of 24 inch diameter, 5.4×1013 atoms·cm−2 or more and 2.2×1014 atoms·cm−2 or less for a crucible of 32 inch diameter, and 1.1×1013 atoms·cm−2 or more and 5.4×1013 atoms·cm−2 or less for a crucible of 40 inch diameter;
- pulling up a single-crystal silicon from the material melt;
- additionally charging a polycrystalline material into a material melt remaining after pulling up the single-crystal silicon and melting the polycrystalline material in the material melt while continuing heating of the material melt;
- and
- pulling up a further single-crystal silicon from the material melt having had the polycrystalline material additionally charged and melted therein, wherein
- the step of additionally charging and melting the polycrystalline material and the step of pulling up the further single-crystal silicon are repeated one or more times, wherein
- in at least one of the steps of pulling up a single-crystal silicon or the step of pulling up a further single-crystal silicon, which is repeated one or more times, the single-crystal silicon is grown in a magnetic field.
Dependencies are inferred from the claim text.