Using MeV ion backscattering/channeling and MC simulations to characterize the composition and structure of buried metal–metal interfaces

Abstract

The technique of MeV ion backscattering and channeling has been used to study the interface structure and stoichiometry for thin transition metal films deposited on Al single crystal surfaces. Analysis of the backscattering data is based on the concepts of shadowing and the well-known theory of Rutherford scattering. In some cases we have used X-ray photoemission spectroscopy (XPS), low-energy (keV) He + ion scattering spectroscopy, and Monte Carlo computer simulations of interface evolution to obtain additional information about the structure of buried interfaces. We first describe the growth of epitaxial fcc Ti films on Al single crystal surfaces, and alloy formation at the epitaxial Ag–Al interface. We next describe measurements for alloy formation at the Ni–Al(1 1 0) interface and present Monte Carlo simulations of the interface evolution. Finally, we describe an approach to stabilize metal–metal epitaxial interfaces using an extremely thin metallic interlayer. Specifically, we show that a single ML of Ti metal deposited at the Fe–Al interface, a system well known for considerable intermixing at room temperature, prevents interdiffusion and enables the epitaxial growth of Fe films on the Al(1 0 0) surface. The resulting structure is observed to be stable for temperatures up to about 200 °C.