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:
Sep. 14, 1976
Filed:
Aug. 28, 1975
Roger A Castonguay, Salem, MA (US);
Martin L Cohen, Belmont, MA (US);
Wilson P Menashi, Lexington, MA (US);
Joseph F Wenckus, Needham, MA (US);
Peter C VonThuna, Lexington, MA (US);
Arthur D. Little, Inc., Cambridge, MA (US);
Abstract
Apparatus is provided for forming, by the Czochralski technique, single semiconductor crystals having essentially uniform diameters throughout their lengths. The apparatus includes means to monitor and control crystal diameter which takes advantage of the fact that the melt volume from which the crystal is pulled and the dielectric crucible containing the melt volume can be incorporated in a crucible assembly circuit in which the resistance varies with the melt volume level in the crucible. Determination of the difference between the measured resistance in the crucible assembly circuit and a programmed reference resistance produces a signal which is used to control one of two operational parameters--the rate at which the crystal is pulled or the temperature of the melt volume--to produce a uniform-diameter crystal.