1. Principle of secondary ion emission

The process of collision cascades leading to ion sputtering is described in Sigmund's model , developed for atomic, elementary and isotropic solids. Part of the energy deposited in the solid is reflected back to the surface via the recoil atoms (target atoms set in motion either by direct collision with the incident particles, or via cascade collisions). If the energy of the latter in the vicinity of the surface is greater than the binding energy of the atoms on the solid surface, they can cause the emission of surface atoms into the vacuum. The rest of the energy deposited by the primary...