Sequential phase formation by ion-induced epitaxy in Fe-implanted Si(001). Study of their properties and thermal behavior

Abstract

The epitaxial growth of FeSi2 silicides was studied by using ion-beam epitaxial crystallization (IBIEC) of Fe-implanted Si(001) samples. By employing Rutherford backscattering/channeling spectrometry and transmission electron microscopy it was possible to determine that the IBIEC process produces a γ-, α-, and β-FeSi2 phase sequence, with increasing Fe concentration along the implantation profile. The critical concentrations for γ→α and α→β phase transitions are 11 and 21 at. %, respectively. A study of the thermal behavior of these phases shows that the γ- and α-FeSi2 are metastable with respect to the β-FeSi2 phase. The γ to β-FeSi2 transition starts at 700 °C via an Ostwald ripening process. In addition a 800 °C, 1 h anneal of high Fe concentration samples produces a complete α and γ to β-FeSi2 transformation. Finally, it is demonstrated that a regular or a rapid thermal annealing on Fe-implanted Si samples induces only the formation of a β-FeSi2 phase.

Lattice strain distribution resolved by X-ray Bragg-surface diffraction in an Si matrix distorted by embedded FeSi2nanoparticles

“…2d), and plate-like nanoparticles rotated with respect to the Si matrix (Fig. 2e), as previously reported (Lin et al, 1994;Behar et al, 1996). The sphere-like nanoparticles form coherent interfaces with the Si matrix, while the platelike ones are elongated along the Sih112i directions when projected along Sih110i.…”

Orientation Analysis of Hexagonal Dendrite Formed from an Undercooled Melt of α-Fe2Si5

“…It is in close agreement with 5.95 deg of the (101) peak of the powdered a-Fe 2 Si 5 in Figure 8(d), although the diffraction angle is slightly decreased due to the lattice expansion at the elevated temperature. Since the diffraction in Figure 8(b) is far from that of 4.53 deg for (111) or 7.40 deg for (220) in the fluorite structure of the metastable cubic c-FeSi 2 , [12] no clear evidence of c-FeSi 2 was found. At the limited time and spatial resolutions, the initial phase that formed at the early stage of the recalescence was the tetragonal a-Fe 2 Si 5 .…”

“…In this alloy system, it was reported that c-FeSi 2 with a cubic structure can be formed in the heteroepitaxial thin layer on the Si substrate. [12] Hence, in the present experiment, the in-situ X-ray diffraction analysis was conducted to identify the phase that can be formed at an early stage of recalescence. Figure 8 shows the result of the in-situ X-ray diffraction taken at BL-11XU in Spring-8, where Figure 8 Figure 8(b).…”

Ion-Beam-Induced Epitaxial Recrystallization Method and Its Recent Applications

“…[11 2] (straight lines) and [100] (dotted line) net patterns (Behar et al, 1996;Vouroutzis et al, 2008). As the SAED measurements have identified two crystalline phases, the near-surface precipitated layer should contain -FeSi 2 nanoparticles.…”