Thin film multilayers of nanometer scale thickness are fundamental to the future of electronics and communications technologies. Chemical depth profiling by ion etching techniques are critical to the characterization of these structures. A fundamental problem with current ion etching technologies is that typical ion energies (~1k eV to 20 keV) create extensive damage and intermixing of nanometer thick multilayer structures, thereby degrading depth profile analysis. In this Phase I project, processes and equipment will be developed and feasibility will be demonstrated for effective compositional depth profiling of nanometer scale multilayer films using low-energy ion etching. In addition, the research to be performed will determine the applicability of low-energy ion etching to the fabrication of nanometer scale multilayer devices. Phase II will develop and deliver to NIST a commercial prototype of a low-energy ion etching system for compositional depth profiling. 4Wave is uniquely qualified owing to its ongoing business in ion beam systems and its unique low-energy ion source technology