Plasma immersion implantation with pulsed anode

Abstract

Method and apparatus for treating a workpiece implantation surface by causing ions to impact the workpiece implantation surface. An implantation chamber defines a chamber interior into which one or more workpieces can be inserted and includes a conductive inner wall portion in proximity to the chamber interior. A conductive workpiece support extends into an interior region of the implantation chamber. A conductive electrode is disposed within said implantation chamber relative to said conductive workpiece support to allow workpieces to be placed on the workpiece support in a region between the support and the conductive electrode. Gas molecules are injected into the implantation chamber to cause the gas molecules to occupy a region of the implantation chamber in close proximity to the one or more workpieces. The gas molecules are ionized near an implant surface of the workpieces. Control circuitry pulses the conductive electrode to a positive potential relative to the conductive workpiece support, the one or more workpieces, and the conductive wall portion of the implantation chamber. The control circuitry includes a voltage source that provides an electric field through which the ionized gas molecules accelerate before striking the implantation surfaces of the one or more workpieces.