The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 28, 1999
Filed:
Sep. 30, 1997
Komatsu Electronic Metals Co., Ltd., Kanagawa, JP;
Abstract
This invention provides a method and a apparatus capable of manufacturing single crystals with an oxygen density of less than 12.times.10.sup.17 atoms/cm.sup.3 or less than 10.times.10.sup.17 atoms/cm.sup.3, and wherein the oxygen density of the single crystal produced is uniformly distributed along its longitudinal axis. The electrical power inputted into the main heater 6 surrounding the quartz crucible 4 and the top heater 9 shaped like a reverse frustrated cone and disposed above the quartz crucible 4, is controlled to keep the temperature of the melt 5 in a preset range during the process of pulling up the single crystal silicon 10. When combining the main heater 6 and the top heater 9, the heat emitted from the main heater 6 can be kept small, and the heat load on the quartz crucible 4 and the amount of oxygen released from the quartz crucible 4 and dissloved into melt 5 can be reduced. Therefore, a single crystal of low oxygen density and with uniformly distributed oxygen density along its longitudinal axis can be obtained. Furthermore, the single-crystal silicon 10 can be assigned a proper thermal history. In the above process, if a magnetic field is applied to the melt, then single crystals of much lower oxygen density can be obtained.