Extraction of ions from the matrix sheath in ablation-plasma ion implantation

A simple one-dimensional theory is presented to assess the implantation of ions from the ion matrix sheath (IMS) in an ablated plasma plume that is ap proaching a negatively biased substrate. Under the assumption that the plum e geometry, the electron and ion density distributions, and the potential d istribution are frozen during the IMS extraction, the implanted ion current is calculated as a function of time for various substrate-plume separation s. This model accurately recovers Lieberman's classic results when the plum e front is initially in contact with the substrate. (C) 2001 American Insti tute of Physics.