Abstract: A technique for using an improved shield ring in plasma-based ion implantation is disclosed. In one particular exemplary embodiment, the technique may be realized as an apparatus and method for plasma-based ion implantation, such as radio frequency plasma doping (RF-PLAD). The apparatus and method may comprise a shield ring positioned on a same plane as and around a periphery of a target wafer, wherein the shield ring comprises an aperture-defining device for defining an area of at least one aperture, a Faraday cup positioned under the at least one aperture, and dose count electronics connected the Faraday cup for calculating ion dose rate. The at least one aperture may comprise at least one of a circular, arc-shaped, slit-shaped, ring-shaped, rectangular, triangular, and elliptical shape. The aperture-defining device may comprise at least one of silicon, silicon carbide, carbon, and graphite.