Formation of an extended CoSi2 thin nanohexagons array coherently buried in silicon single crystal

Abstract

A Co-doped silica film was deposited on the surface of a Si(100) wafer and isothermally annealed at 750 °C to form spherical Co nanoparticles embedded in the silica film and a few atomic layer thick CoSi2 nanoplatelets within the wafer. The structure, morphology, and spatial orientation of the nanoplatelets were characterized. The experimental results indicate that the nanoplatelets exhibit hexagonal shape and a uniform thickness. The CoSi2 nanostructures lattice is coherent with the Si lattice, and each of them is parallel to one of the four planes belonging to the {111} crystallographic form of the host lattice.

Controlled growth of extended arrays of CoSi2 hexagonal nanoplatelets buried in Si(001), Si(011) and Si(111) wafers

“…1 that the angle between the main faces of all observed CoSi 2 nanoplatelets and the Si(001)/ SiO 2 interface is a = 54.71, this value being the angle between each plane of the Si{111} crystallographic form and the Si(001) plane. These observations confirm the previous results stating that the main faces of all CoSi 2 nanoplatelets buried in the Si(001) wafer are oriented parallel to crystallographic planes of the Si{111} form, 18 exhibiting a four-fold rotation symmetry around the Si[001] crystallographic direction.…”

“…18 The small relative dispersion in the nanoplatelet thickness s t /hti = 0.14 obtained for Si(001) wafer confirms the rather small thickness dispersion in this parameter as previously reported.…”

“…1 exhibit the same overall features as those corresponding to a previous study of a similar sample, namely Co NP randomly dispersed in the SiO 2 thin film and CoSi 2 nanoplatelets regularly buried in the Si(001) wafer. 18 In the mentioned previous work it was also demonstrated that the CoSi 2 nanoplatelets exhibit a CaF 2 crystallographic structure and their lattices are coherently related to the cubic lattice of the host Si matrix. We notice in Fig.…”

“…13,[15][16][17] A simple procedure for obtaining buried arrays of CoSi 2 nanoplatelets coherently embedded in a Si(001) host lattice was described in a recently published study. 18 In this investigation it was demonstrated that thermally activated diffusion of Co atoms from the supported Co-doped SiO 2 thin film into a flat Si(001) wafer substrate promotes the formation of a regular array of oriented CoSi 2 nanoplatelets buried in the Si single crystal. The analysis of TEM images indicated that the CoSi 2 nanoplatelets exhibit a CaF 2 -like atomic structure, hexagonal lateral shape and a remarkable uniform thickness.…”

In situ study of the endotaxial growth of hexagonal CoSi2 nanoplatelets in Si(001)

“…During the last decades, a number of authors have investigated the formation of nano-objects deposited to or grown on external surfaces of different single crystalline substrates. [1][2][3][4][5][6][7][8][9][10] The knowledge of the relevant features and the control of the growth processes of these nanostructures are of particular relevance because the properties of these materials strongly depend on the sizes and shapes of the basic building blocks. [11][12][13][14][15][16][17] In the particular case of silicides obtained by deposition of transition metals on silicon singlecrystals under ultra-high vacuum conditions, they selfassemble into high aspect ratio nanowires.…”