The solid-state reaction between monocrystalline AlGaAs(100) and polycrysta
lline Fe films, having thickness in the 50-100 nm range, has been investiga
ted using X-ray diffraction, conversion electron Mossbauer spectroscopy and
transmission electron microscopy. The Fe films were deposited on ion-etche
d semiconductor substrates using an ion-beam-sputtering technique. It has b
een found that, in the as-deposited state, the thickness of the interfacial
zone never exceeds 1.5 nm, a value comparable to that obtained for Fe film
s deposited by molecular-beam-epitaxy. The interface reaction of the Fe fil
ms was also studied after annealing in vacuum at 400 degreesC for 1 h. The
orientation of the magnetization and the grain size of the deposited metall
ic layers are reported for the as-deposited, as well as for the annealed fi
lms. Interdiffusion after annealing mainly results in the generation of Fe2
As grains. These grains were observed in the AlGaAs substrate, exactly unde
r the Fe/AlGaAs interface, and they have a triangular shape; this is the fi
rst report on the formation of grains with such a shape. Additional analysi
s on the orientation relationship between the Fe2As grains and the substate
was carried out and the results are also presented here. Studies concernin
g the diffusion of Al, Ga and As atoms into the Fe overlayer revealed the l
ow mobility of As, as compared to Al and Ga. (C) 2000 Elsevier Science B.V.
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