Synthesis and characterization of nanostructures with ion beams

André Vantomme

Ion beams, produced by high-energy particle accelerators, are well-know from a wide variety of nuclear physics studies. On the other hand, ion beams have also a strong potential in modifying and/or characterizing materials properties, even down to the nm region. At the heart of these phenomena is the transfer of energy from the ion to the target nuclei and electrons. In this lecture, a number of examples will be presented which are commonly used in micro (or nano) electronics related research.

The most well-known application is ion beam doping, i.e. adding a small concentration of dopants (in a controlled way !) with the intention of tailoring the electronic, optical, magnetic… properties. On the other hand, larger concentrations can result in spontaneous precipitation of the implanted dopants into nm-sized clusters, an approach known as ion beam synthesis.

Alternatively, rather than introducing foreign species, the aim of ion bombardment can be to locally deposited energy, i.e. ion irradiation. As a result of this irradiation, functional materials properties can be drastically altered, as will be demonstrated for magnetic coupling. Furthermore, the deposited energy can be used to locally remove target material, e.g. sputtering, ion beam writing, ion beam sculpting…

Finally, the interaction of (typically light) energetic ions can also be used to characterize the materials properties. The transfer of energy from the ion to the target atoms provides detailed information on the identity, the distribution, concentration, crystalline structure, etc. of the target.