METHODS AND APPARATUS FOR ION BEAM NEUTRALIZATION IN MAGNETS

摘要

A magnet assembly is provided for use with an ion beam. The magnet assembly includes a magnet disposed in the path of the ion beam and an electron source. The magnet includes first and second polepieces spaced apart to define a magnet gap through which the ion beam is transported. The electron source is disposed on or in proximity to at least one of the polepieces for producing low energy electrons in the magnet gap. The electron source may include a one or two dimensional array of electron emitters or one or more linear electron emitters, for example. The magnet assembly may be utilized in an ion implanter to limit space charge expansion of the ion beam in the magnet gap.