Several techniques, presently available to study the atomic structure of interfaces are compared. The ion focusing technique, which is based on the principles of ion channeling and blocking is described in detail, and results for the NiSi2-Si(iil) system are presented. The interface structure is shown to consist of sevenfold coordinated Ni atoms and the bonding distance across the interface has been measured with an accuracy of 0.008 rim. These results are compared with results obtained from high-resolution TEM lattice imaging and the x-ray standing wave method. © 1986, American Vacuum Society. All rights reserved.