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:
Nov. 23, 1993
Filed:
Aug. 21, 1992
Mitsubishi Materials Corporation, Tokyo, JP;
Abstract
An apparatus for growing silicon single-crystals comprising a crucible containing a silicon melt, a furnace for housing the crucible and having an opening located above the crucible, a pulling mechanism for pulling a seed crystal from the melt to grow a silicon single-crystal, a cooling shell having a lower end spaced apart and located above the melt and disposed around said silicon single-crystal for cooling the silicon single crystal from a temperature of 1,050.degree. to 850.degree. C. in no more than 140 minutes as it is being pulled, and, a secondary heater for heating the silicon single crystal as it is being pulled, such that the dwelling time of the single crystal in a temperature zone of 800.degree. C. to 600.degree. C. is at least two hours. The secondary heater is disposed above the cooling shell and coaxial therewith and is arranged so as to define a space between the secondary heater and the cooling shell. Means for introducing an argon flow through the secondary heater into the cooling shell is located at the furnace opening. The argon gas flow is partially diverted by the space between the secondary heater and the cooling shell resulting in a silicon single-crystal having increased oxygen precipitate distribution.