Electrical and optical characterization of GdSi2 and ErSi2 alloy thin films

Abstract

GdSi2 and ErSi2 polycrystalline thin films were studied using electrical resistivity in the temperature range 10–900 K, Hall effect from 10–300 K and reflectivity spectra from 0.2–100 μm at room temperature. Composition and structure in these films were investigated by Rutherford backscattering spectroscopy and x-ray diffraction techniques. These silicides are metallic with (i) a remarkable difference in their residual resistivity, (ii) a phonon contribution to the resistivity which showed a negative deviation linearity, and (iii) low energy interband transitions. Resistivity data indicated that GdSi2 and ErSi2 have a Debye temperature of 328 and 300 K respectively and a limiting resistivity value much higher than that observed in other transition metal disilicides. The charge carrier concentration was estimated to be 4×1021 cm−3 at room temperature according to Hall measurements, and the mean free path was 63 Å and 320 Å for GdSi2 and ErSi2, respectively, at 10 K. The parameters obtained by the optical analysis are in good agreement with those extracted from the transport measurements, thus permitting one to obtain a reasonable value for the Fermi velocity.

Epitaxial samarium disilicide films on silicon (0 0 1) substrates: growth, structural and electrical properties

“…A full discussion of this phenomenon is beyond the scope of this paper and needs further investigations. Both the intrinsic resistivity and ambient-temperature resistivity of films are somewhat larger than found for ErSi 1−x [8,10], GdSi 1−x [10,32] and DySi 2−x [20], but comparable to most other RESis [20,22,33]. By decreasing the thickness of the SmSi 2 films towards 40 nm there is a moderate increase in the resistivity, ρ 4 K = 100 µ cm still comparable to the intrinsic phonon-limited resistivity ρ in = ρ 300 K − ρ 4 K = 116 µ cm (figure 5).…”

Europium Silicide – a Prospective Material for Contacts with Silicon

“…The resistivity of EuSi 2 changes from 37 μOhm·cm at room temperature to 2.1 μOhm·cm at 2 K. The residual resistivity is significantly smaller than that observed for ErSi 2 50 or ErSi 1.7 51 thin films. Hall effect measurements of our films determine the electron concentration about 10 22 cm −3 .…”

Epitaxial Growth and Electrical Properties of Thick SmSi2 Layers on (001) Silicon

“…The high-field limit at 300 K indicate the same carrier sign and concentration within %30%. Previous reports of silicides have shown both n-and p-type conduction, 2,33) with carrier concentrations on the order of 5 Â 10 21 cm À3 .…”