Interior Surface Plasma Immersion Ion Implantation of a Small Cylindrical Bore Using a Noncoaxial Parallel Auxiliary Electrode

Plasma immersion ion implantation can be used to process the interior surfaces of oddly shape structures, such as a cylindrical bore. A small cylindrical bore with a grounded noncoaxial parallel auxiliary electrode is modeled using a 2-D particle-in-cell model. Simulation shows that, after the ions initially present in the bore begin to be exhausted, an ion density pulse is formed, which sweeps the interior surface of the bore. Moreover, a corresponding ion dose peak sweeps along the surface from the point nearest to the auxiliary electrode to a point further than the auxiliary electrode if the negative pulse is maintained at the bore. A nonuniform ion implantation on the inner surface of the bore is caused by the deviation of the noncoaxial parallel auxiliary electrode from the axis of the bore after all the ions in the bore have been exhausted.