Shadow Effects in Mesh-Assisted Plasma Immersion Ion Implantation of Insulating Materials

Plasma immersion ion implantation (PIII) has been proven to be an effective technique to optimize the surface properties of conductive materials such as steels, aluminum, titanium, and semiconductors. However, implanting insulating materials such as biomedical, ceramic, and polymeric materials is quite challenging. This is due to the low potential on the insulating samples even if a higher negative potential is applied to the sample holder. In order to effectively conduct PIII of insulating materials, a metal mesh covering the insulating samples can be used. The high voltage is applied to the conducting mesh and ions are implanted into the insulating specimens via the grid holes. Our experimental results show that this method is very effective and increases the net incident energy of the ions. Unfortunately, the grids give rise to shadowing effects on the specimens and in this presentation, this mesh shadowing effect is reported and discussed. The investigation focuses on the influence of bias-potential variation (from 10 kV to 30 kV) and the distance between the mesh and the samples.