Phase selective synthesis of gadolinium silicide films on Si(111) using an interfacial SiO2 layer.

We synthesized a single phase GdSi[sub 2] film on a Si(111) substrate with an interfacial SiO[sub 2] layer. In order to take account of the role of the interfacial SiO[sub 2] layer, systematic investigations on clean and oxidized Si substrates were done by using in situ reflection of high energy electron diffraction, x-ray diffraction, and atomic force microscopy of the silicides formed with post annealing. Our result showed that the interfacial SiO[sub 2] layer enhanced the structural transformation of the initial GdSi[sub 1.7] hexagonal phase into the GdSi[sub 2] orthorhombic phase above the decomposition temperature of SiO[sub 2](∼800 °C). We proposed a reaction mechanism for the GdSi[sub 2] film formation with the help of the interfacial SiO[sub 2] layer. The measured electrical resistivity of the Gd-silicide film strongly depends on the silicide phase. [ABSTRACT FROM AUTHOR]