Abstract: An apparatus and method for processing the surface of a substrate with a plasma formed from a process gas comprises a processing chamber defining a plasma source region and a processing region wherein electrical energy is coupled into the source region to form and sustain a plasma therein, and an ion extraction mechanism positioned between the source region and processing region for extracting ions from the plasma and directing extracted ions and neutral particles into the processing region to process a biased substrate therein. A gas-dispersing element in the processing space disperses a process gas to intersect paths of the extracted ions and to produce charge exchange collisions to create a large number of high-energy neutral particles for processing the workpiece.