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:
Jan. 16, 1979
Filed:
Apr. 13, 1977
Robert J Lavigna, Bath, PA (US);
Charles W Pearce, Allentown, PA (US);
Raymond E Reusser, Bethlehem, PA (US);
Western Electric Company, Inc., New York, NY (US);
Abstract
To improve the control over resistivity of grown single crystalline ingots, to reduce the turn-around time between growth of successive ingots in a particular crystal grower and to enable recycling of otherwise junk material, a sample of a molten material (the 'melt') from which the ingot is to be grown is withdrawn from the crystal grower, cooled, and analyzed. Based on the analysis, controlled additional amounts of the material and/or a dopant impurity are added directly to the melt to restore it to a desired chemical composition. Thus, avoidable is costly and time-consuming cooling of the melt and restarting the system with a completely new charge of material and impurity, and achievable is uniformity of resistivity among the successively grown ingots. Preferably the sample is withdrawn from the melt into a quartz tube which is inserted into the system through a port. The sample is rapidly cooled and solidified and inserted into a waveguide system where a microwave absorption measurement provides a number which is readily converted into resistivity of the sample, and then, into doping level of the melt.