ELASTIC AND INELASTIC PROCESSES IN THE INTERACTION OF 1-10 EV IONS WITH SOLIDS - ION-TRANSPORT THROUGH SURFACE-LAYERS

We review the escape depth of secondary ions (or neutrals) desorbing f rom solid surfaces under the impact of electrons, photons or ions. We survey ion(or neutral) transport through many materials, but most are wide band gap insulators such as rare-gas solids and molecular solids. We address the issue of low-energy (<10 eV) ion-solid interactions, a nd review experimental and theoretical studies that provide insight in to the physical mechanisms of these interactions, such as elastic scat tering, charge transfer and ion-molecule reactions, Although it is usu ally assumed that most of the secondary ions stem from the top surface layer, we show that this is not necessarily the case: In certain inst ances, 1-10 eV ions are able to transmit solid films which are several monolayers thick. The transport of low-energy ions through materials has very broad implications. We point out the importance of these resu lts for election or photon stimulated desorption (ESD/PSD), secondary ion mass spectrometry (SIMS), and ion-sputtering of surfaces, and disc uss their relevance to other fields, such as ion beam deposition (IBD) , low-energy ion implantation, and electrochemistry.