Ion scattering studies of the formation and thermal stability of the Ti–Al interface

Abstract

Promoting the ordered growth of component thin films with chemically abrupt interfaces for magnetic/non-magnetic metal/metal systems, such as Fe/Al, is an important problem in magneto-resistive device technology. The focus of the present investigation is the Ti–Al interface, a stable template for promoting epitaxial growth of Fe films. The present work was performed to characterize the formation and thermal stability of the Ti–Al interface and thereby provide a better understanding of the physical mechanisms underlying the success of the Fe–Ti–Al interlayer concept, and how it might be extended to other metal–metal systems. We investigated interface formation for thin Ti films deposited on Al(1 0 0) surfaces at room temperature using low-energy ion scattering spectroscopy and Rutherford backscattering. The results indicate that Ti does not grow in a simple layer-by-layer fashion for initial deposition on Al(1 0 0), but are instead more consistent with some combination of island growth and/or alloy formation at the interface. The Ti films are stable up to temperatures on the order of 673 K, at which point Ti diffuses into the Al lattice to occupy substitutional sites.