PROCESS GAS ENHANCEMENT FOR BEAM TREATMENT OF A SUBSTRATE

A beam processing system and method of operating are described. In particular, the beam processing system includes a beam source having a nozzle assembly that is configured to introduce a primary gas through the nozzle assembly to a vacuum vessel in order to produce a gaseous beam, such as a gas cluster beam, and optionally, an ionizer positioned downstream from the nozzle assembly, and configured to ionize the gaseous beam to produce an ionized gaseous beam. The beam processing system further includes a process chamber within which a substrate is positioned for treatment by the gaseous beam, and a secondary gas source, wherein the secondary gas source includes a secondary gas supply system that delivers a secondary gas, and a secondary gas controller that operatively controls the flow of the secondary gas injected into the beam processing system downstream of the nozzle assembly.