Electron impact ion source
View Patent ↗An ion source configured for integration into both existing ion implanters used in semiconductor manufacturing and emerging ion implantation platforms. The ion source in accordance with the present invention includes the following features, all of which depart from the prior art to produce a well-focused, collimated and controllable ion beam. These features include: ionizing electron beams generated external to the ionization chamber, thereby extending the emitter lifetime; 90 degree magnetic deflection of electron beams such that no line-of-sight exists between the emitter and the process gas load, and the emitter is protected from bombardment by energetic charged particles; two opposed electron beams which can be operated simultaneously or separately; and use of a deceleration lens to adjust the final energy of the electron beam, substantially without affecting electron beam generation and deflection.
1. An ion source comprising:
an ionization chamber, said ionization chamber including a vapor entrance aperture for receiving gaseous feed material, an extraction aperture for emitting an ionized beam and one or more electron entrance apertures, each of said one or more electron entrance apertures being disposed in a plane;
one or more electron beam sources for generating one or more electron beams, each of said one or more electron beam sources disposed to generate one or more electron beams in a direction generally parallel to the plane of its respective electron entrance aperture; and
one or more beam steerers for bending said one or more electron beams so that said one or more electron beams travel in a direction to be received in said one or more electron entrance apertures.
2. The ion source as recited in claim 1 , wherein each of said beam steerers includes a magnetic field source configured to generate a magnetic field in a direction generally perpendicular to said electron beam.
3. The ion source as recited in claim 2 , wherein at least one of said one or more electron beam sources is a filament.
4. The ion source as recited in claim 1 , wherein at least one of said one or more magnetic field sources includes a permanent magnet.