ELSEVIER Surface Science 365 (1996) 78-86 surface science Room temperature growth of thin Fe films on AI(001) and A1(110) surfaces N.R. Shivaparan, V. Krasemann, V. Shutthanandan 1, R.J. Smith * Physics Department, Montana State University, Bozeman, M T 59717, USA Received 16 October 1995; accepted for publication 19 January 1996 Abstract The growth of thin Fe overlayers on A1(110) and AI(001) surfaces has been investigated using high-energy ion backscattering (HEIS) and X-ray photoelectron spectroscopy (XPS), for Fe coverages from 0 to 15 ML deposited at room temperature. For the AI(001) surface, measurements of the backscattered ion yields from A1 and Fe atoms show that the Fe atoms do not form a simple overlayer on the AI substrate, but displace A1 atoms from their equilibrium positions to form a mixture of FeAI. The inter-mixing continues up to about 5 ML Fe coverage before Fe metal begins to cover the mixed surface. For the AI(ll0) surface, intermixing of Fe and A1 atoms was observed up to about 9 ML Fe deposition, where Fe metal begins to cover the surface. In neither case was Fe diffusion into the bulk A1 substrate observed. XPS results show no chemical shift larger than the resolution of our measurements for the Fe 2p core level in Fe aluminides. The variation of the Fe XPS photopeak intensity as a function of Fe coverage also supports the two- and three-stage growth models on AI(001) and AI(110) surfaces, respectively. Keywords: Aluminum; Epitaxy; High energy ion scattering; Iron; Metal-metal interfaces; Single crystal surfaces; X-ray photoelectron spectroscopy I. Introduction Over the last few years, ultra-thin metal film growth on metal substrates has attracted consider- able attention in the surface science community. In part this is because of the desirable properties which the intermetallics offer for potential high- temperature structural applications [ 1 ]. For exam- ple, the iron aluminide alloys have a low material density, low cost and good oxidation resistance. 1 Present address: Electric Propulsion Laboratory, Department of Mechanical Engineering, Tuskegee University, Tuskegee, AL 36088, USA. *Corresponding author. Fax: + 1 406 994 4452; e-mail: smith@physics.montana.edu The magnetic properties of Fe are also important for recording-head applications. Iron exhibits the largest saturation magnetization among all pure metals at room temperature. The soft magnetic properties of Fe films can be further improved by forming multilayer structures [2,3]. A good exam- ple of such a system is Fe/A1 [4]. Finally, the Fe-A1 system has also attracted attention as a possible metallization material on InP, because of the good lattice matching and relative stability of the intermetallic on this substrate [5]. For all of these reasons it is useful to study the structure of Fe-A1 interfaces. In addition, this work adds to our growing understanding of metal-metal interface structure and metal film growth. Recently, several groups have studied the growth 0039-6028/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved PII 0039-6028(96)00584-5