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

Abstract

We report on the growth of thick (up to 1.2 mm) epitaxial samarium disilicide layers on (001) oriented silicon substrates. The films have the bulk tetragonal SmSi 2 structure and composition, and grow with a preferential orientation SmSi 2 [100] k Si[110]. A surface reconstruction transition from (1Â1) to (2Â2) appears below $525 C. Transport measurements show an n-type metallic conduction with a room temperature resistivity of 175 m cm decreasing to 85 m cm at 4 K, and a carrier concentration of 1:3 Â 10 22 cm À3 .

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

“…By increasing the growth temperature, the shape of the diffraction pattern becomes sharper and more intense; from modulated at 500 • C (figure 1(b)) and then streaky, indicating a very smooth, flat growing surface, at even higher temperature (figure 1(c) for T g = 650 • C). Upon further growth at 600-650 • C to increase the thickness, the RHEED pattern results in sharper and more intense diffraction streaks [23]. This phenomenon is not observed for layers [25].…”

“…We also observe a (2 × 2) surface reconstruction on the RHEED patterns, whose intensity progressively vanishes when the SmSi 2 surface becomes more and more rough, from the 2D to 3D character of the surface. Further details about this surface reconstruction can be found elsewhere (see [23]).…”

“…SmSi 2 films from 250 nm to 1.3 µm thick grown at 600-650 • C showed a temperature-dependent resistivity typical of a metal [23]. The residual resistivity ρ 4 K = 80 µ cm is comparable to the intrinsic phonon-limited resistivity ρ in = ρ 300 K − ρ 4 K = 90 µ cm, indicating a moderate level of disorder scattering [23]. There is no evidence of an anomaly that might signal a magnetic ordering temperature as has been reported for ErSi 2 [8], GdSi 1.7 [10] or DySi 2−x [18].…”

“…However the few results available demonstrate that ErSi 1.7 [17][18][19], DySi 1.7 [20], GdSi 2 [21] and LuSi 1.7 [22] can be grown epitaxially onto (0 0 1) oriented silicon surfaces. Recently, we have expanded this set by growing epitaxially SmSi 2 films on Si(0 0 1) [23]. In this work we explore the effect of the growth temperature on the structural, electrical and optical properties of epitaxial SmSi 2 thin films grown by reactive-deposition epitaxy (RDE) on Si(0 0 1).…”

Growth and structure characterization of EuSi 2 films and nanoislands on vicinal Si(001) surface

“…By changing the growth temperature 3D RE silicide nanoislands and clusters have been formed [1,9]. RE silicide films (Tb, Er) have first been studied by Baglin et al [10] followed by investigations of Dy [11], Er [12 14] and Sm [15] silicide epitaxial films with thicknesses up to 1.2 μm.…”