Theoretical Considerations on Ion Channeling Effect through Silicide-Silicon Interface

The ion channeling effect in hetero-epitaxial structures is considered theoretically. Four dechanneling factors at the film-substrate interface are discussed, i.e., (1) a transition layer, (2) lattice imperfection due to the mismatch of lattice parameters, (3) discontinuity of atomic rows, and (4) deformation of the potential distribution inside a channel. These conditions are then applied to practical silicide-on-silicon structures, the metal elements and composition ratios suitable for epitaxial growth on Si substrates being determined from the lattice matching conditions, and the behavior of channeled ions at the interface being predicted using the dechanneling factors (3) and (4). It is concluded that the dechanneling probability is lowest for NiSi 2 and CoSi 2 on Si structures, and that a pronounced flux peaking effect is expected to be caused by the host atoms in a CrSi 2 on Si structure.