N type impurity doping using implantation of P₂+ ions or As₂₊ Ions

摘要

A method for using ion implantation to implant phosphorous or arsenic impurities into shallow source/drain regions or into polysilicon electrodes used in devices having shallow source/drain electrodes. A phosphorous source having an abundance of P₂+ ions is used in an ion beam system adjusted to select P₂+ ions. Since each ion contains two phosphorous atoms the ion beam requires twice the beam energy and half the beam density. This provides good wafer throughput and improved source life. An arsenic source having an abundance of As₂+ ions can be substituted for the solid phosphorous source resulting in a beam of As₂+ ions.