Characteristics of the surface-wave plasma generated by a radial-line slot antenna (RLSA) have been studied by both direct plasma probe measurements and numerical simulations. Some unique characteristics have been found, including excellent critical radial plasma uniformity, low electron temperature under various pressure conditions, the main plasma generation area of RLSA being limited in the plasma surface, and few high-energy electrons existing in the wafer region. Numerical simulations are implemented to reveal the more essential difference in plasma generation between the RLSA and the other plasma sources, where the superiority of RLSA plasma has been confirmed. The features of high plasma uniformity and low electron temperature lead to free plasma damage in our associated etching process. (c) 2006 American Vacuum Society.