Plasma implantation using halogenated dopant species to limit deposition of surface layers

摘要

Methods and apparatus for plasma implantation of a workpiece, such as a semiconductor wafer, are provided. A method includes introducing into a plasma doping chamber a dopant gas selected from the group consisting of PF₃, AsF₃, AsF₅ and mixtures thereof, forming in the plasma doping chamber a plasma containing ions of the dopant gas, the plasma having a plasma sheath at or near a surface of the workpiece, and accelerating the dopant gas ions across the plasma sheath toward the workpiece, wherein the dopant gas ions are implanted into the workpiece. The selected dopant gas limits deposition of neutral particles on the workpiece.