Patent ID: 6204508
Filing Date: 2001-03-20
Classification: H01J

Abstract:
An ion source (10) for an ion implanter, comprising:(i) an arc chamber (12) formed by walls (14);(ii) an inlet (16) for introducing an ionizable gas into said arc chamber;(iii) an exit aperture (22) from which an ionized plasma may be extracted; and(iv) a filament (18) having first and second legs (20a, 20b) and a thermally emissive central portion (40) having ends connected, respectively, to said first and second legs, said thermally emissive portion formed into two halves (40a, 40b) coiled in opposite directions substantially along the entire length thereof and formed in the shape of a generally closed loop, wherein coils of said thermally emissive portion (40) establish closed loop magnetic field lines (B) therein when electrical current flows through said thermally emissive portion, and wherein said closed loop magnetic field lines (B) confine electrons (E) emitted from the surface of said thermally emissive portion (40) within the confines of said coils.