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:
Feb. 13, 1990
Filed:
Mar. 13, 1989
Wolfgang Keller, Munich, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
For floating zone drawing of semiconductor rods having diameters greater than 100 mm, at the beginning of the zone drawing process, in particular during melting on of the seed crystal to the semiconductor rod to be drawn, a high load change and impedance change occurs. The power from the high-frequency (HF) generator is no longer coupled thereto optimally. Heating up the feed line to the induction heating coil is the result. This heating is avoided by connecting the HF generator via a feed line to a tank circuit device. A variable tank circuit capacitor connected in parallel and to the series oscillator circuit coil feeding one side of a parallel circuit of a heating circuit capacitor and the induction heating coil. The variable oscillator circuit capacitor is adjusted as a function of the voltage drop across the induction heating coil.