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:
Oct. 02, 2000
Filed:
Apr. 14, 1998
Anthony E Robson, Alexandria, VA (US);
United States of America, Washington, DC (US);
Abstract
A method of and apparatus for controlling the potential of a plasma including a metal-walled chamber and a conductive coil which carries a radio-frequency current and is wrapped around the metal-walled chamber to produce a plasma within the chamber. A filament made of refractory metal has two ends, and a central portion formed in the shape of a probe. The central portion of the filament extends into the interior of the chamber and the two ends of the filament pass through a wall of the chamber to the exterior of the chamber. A heating power supply is connected to the two ends to the filament and to the chamber wall for heating the filament to a predetermined temperature above that of the plasma. The heated filament produces thermionic emissions from the filament to the plasma in order to control the plasma potential and eliminate unipolar arcing at the chamber wall.