Ion Implantation for Material Property Modification

Compositional and structural change

The goal of ion implantation is to add ions to the interior of a substrate to change its material properties. The incoming ions change the elemental composition, but they also induce a structural change because they transfer energy and momentum to the substrate. The penetration depth of the ions can be tuned with the ion energy and depends on the charge and type of ion and the nature of the substrate. Our ion sources typically deliver singly charged ions.

What happens subsurface

As they travel through the solid substrate the implanted ions gradually lose their energy until they come to a halt. At high energies they slow down primarily by inelastic collisions with bound electrons in the substrate. At lower energies the collisions with the nuclei of the substrate atoms become dominant (so-called collision cascades). Atoms of the solid will be permanently displaced from their lattice position when they receive more energy than their threshold displacement energy (typically tens of eV). If they receive a lot more, these displaced atoms can produce cascades of collisions of their own.

Ion implantation applications

Ion implantation is used for example in tool steel toughening, medical implants, and in semiconductor device fabrication. Some of the surface properties that can be modified are: