Patent ID: 8716682

Claim:
An ion implantation system, comprising: a plasma source for providing a plasma; a workpiece holder arranged to receive a bias with respect to the plasma to attract ions across a plasma sheath toward a workpiece, the workpiece having a front surface defining a workpiece plane; and an extraction plate arrangement having a plurality of apertures each arranged to provide an ion beam having ions distributed over a range of angles of incidence on the workpiece, wherein a first ion beam extracted from a first aperture has a first distribution of angles of incidence and a second ion beam extracted from a second aperture has a second distribution of angles of incidence that is different than the first distribution, wherein the first distribution of angles of incidence comprises a bimodal distribution of angles in which a current density of ions that impinge upon the workpiece is greater about a first and second peak angles as compared to a current density of ions that impinge upon the workpiece between the first and second peak angles.