Abstract

Energetic ions penetrating a solid lose their energy by nuclear interaction with one or more target atoms as well as by electronic excitation of the target atoms. The energy loss by nuclear interaction can be described in the classical ballistic way. Target atoms, put into motion by a primary collision, can exchange momentum with surrounding target atoms. This results in implantation of primary ions and damage in the target structure. A part of the momentum exchange is reversed in the direction of the target surface. This can give rise to the release of surface atoms, which is known as sputtering. Momentum transfer at an interface of two different materials will give rise to intermixing as demonstrated by van der Weg¹⁾. Fundamental research²⁾ revealed that ion beam mixing could not only be explained by ballistic effects, but that also thermodynamic and chemical effects play a role. These effects are expected to take place in the end of a cascade formation, when the average energy is smaller than 1 eV. Further experiments have shown the importance of radiation enhanced diffusion, which shows up as a temperature dependent effect for a temperature higher than a critical value. The physics of this effect is based on vacancy enhanced diffusion.

© 1994 Optical Society of America