Patent ID: 6501081
Filing Date: 2002-12-31
Classification: H01J

Abstract:
Electron flood apparatus for neutralising positive charge build up on a substrate during implantation of ions in the substrate by ion implantation apparatus, the substrate being connected to a common terminal, the electron flood apparatus comprising:a tube for axially receiving and passing an ion beam to a substrate, an opening in a side wall of the tube, a plasma chamber having an exit aperture in communication with said opening of said tube, a supply of inert gas to said plasma chamber, a cathode in said plasma chamber, a cathode power supply connected to heat said cathode to emit electrons, said plasma chamber providing an accelerating electrode within said chamber, an accelerating electrical supply connected to provide an accelerating potential between said cathode and said accelerating electrode to accelerate electrons emitted by said cathode to produce a plasma in said chamber, and a cathode bias electrical supply for connection directly between said cathode and said substrate common terminal to set a desired bias potential on said cathode relative to said substrate independently of said accelerating potential.