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:
Jun. 01, 1999
Filed:
Sep. 08, 1997
Peter L Kellerman, Essex, MA (US);
James D Bernstein, Beverly, MA (US);
Brian S Freer, Medford, MA (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
A plasma-enhanced electron shower (62) for an ion implantation system (10) is provided, including a target (64) provided with a chamber (84) at least partially defined by a replaceable graphite liner (82). A filament assembly (67) attached to the target generates and directs a supply of primary electrons toward a surface (118) provided by the graphite liner, which is biased to a low negative voltage of up to -10V (approximately -6V) to insure that secondary electrons emitted therefrom as a result of impacting primary electrons have a uniform low energy. The filament assembly (67) includes a filament (68) for thermionically emitting primary electrons; a biased (-300V) filament electrode (70) for focusing the emitted primary electrons, and a grounded extraction aperture (72) for extracting the focused primary electrons toward the graphite surface (118). A gas nozzle (77) attached to the target (64) introduces into the chamber a supply of gas molecules to be ionized by the primary electrons. The direction of the nozzle is set with respect to the filament assembly (67) to maximize the ionization rate of the gas molecules.