An apparatus and method of doping ions into a substrate are disclosed and include a process chamber having an inner space in which an ion implantation process is performed, a support unit positioned in the process chamber, supporting a substrate and being electrically connected to a first power source for generating a high frequency pulse, a conductive unit separated from the support unit in such a manner that plasma associated with the ion implantation process is generated between the support unit and the conductive unit, wherein the conductive unit comprises a first etch prevention member preventing the conductive unit from being etched by a source gas used to generate the plasma, and a power port electrically connected to a second power source and generating radio frequency (RF) power applied to the conductive unit.