Patent ID: 7132672
Filing Date: 2006-11-07
Classification: H01J

Abstract:
1. A plasma doping apparatus comprising: a plasma doping chamber; a platen mounted in said plasma doping chamber for supporting a workpiece; a source of ionizable gas coupled to said chamber, said ionizable gas containing a desired dopant for implantation into said workpiece; a plasma source for producing a plasma having a plasma sheath in the vicinity of said workpiece, said plasma containing positive ions of said ionizable gas, and accelerating said positive ions across the plasma sheath toward said platen for implantation into said workpiece; an annular Faraday cup disposed around said platen for collecting a sample of said positive ions accelerated across said plasma sheath, said sample being representative of the number of positive ions implanted into the workpiece; and magnetic field generating means positioned beneath a collecting surface of said Faraday cup to generate a magnetic field at the collecting surface of said Faraday cup for suppressing escape of secondary electrons from said Faraday cup.