Surface structures of erbium silicide ultra-thin films formed by solid phase epitaxy on Si(1 0 0)

Formation of ytterbium silicide film on Si(001) by solid-phase epitaxy

“…A close inspection of this STM image reveals that the islands are preferably elongated in the either [1 1 0] or ½1 1 0 direction. This is reminiscence of the growth of hexagonal RE silicide nanowires on Si(0 0 1) with the epitaxial relationship of ½1 1 2 0RESi 2Àx J[1 1 0] or ½1 1 0Si [6][7][8][9][10][11][12][13][14]. As remarked above, due to a rather good lattice match along one silicide axis and a poor match along the other, the anisotropic strain of hexagonal Yb silicide can indeed favor the preferable growth along one of these Si directions.…”

“…It is not clear enough whether such a structure can be compatible with AlB 2 and Th 3 Pd 5 structures found for silicon-rich Yb disilicides [21]. However, it is different from the 1 Â 1 reconstruction on the top of hexagonal Yb silicide nanowires [16] as well as the c(2 Â 2) and 2 Â 1 reconstructions on the top of other hexagonal RE silicide nanowires [8,9,[12][13][14]. Therefore, we can presume that 3D clusters crystallize in distinct structure, as compared to that of hexagonal Yb silicide nanowires.…”

“…It was shown that the formation of such nanowires is favored by epitaxial relationship of hexagonal silicide and Si(0 0 1) surface lattices, where the ½1 1 % 2 0 and [0 0 0 1] silicide axes lie in the substrate surface plane and are aligned along the [1 1 0] Si directions. In particular, the long nanowires were reported recently for Dy [6,[8][9][10], Er [7,[10][11][12], Ho [8,13], and Gd [10,14] that provide a very low lattice mismatch along the [11][12][13][14][15][16][17][18][19][20] axis (about 1% or below) and much larger mismatch along the [0 0 0 1] axis (about 7%). In contrast, Nd silicide is poorly matched with Si(0 0 1) along the both axes, yielding the formation of compact 3D islands [15].…”

Synthesis of very long ErSi2 nanowires on Si substrates

“…Due to its low resistivity (3.5 Â 10 À7 Om in bulk) and low schottky barrier height to Si [6,7], ErSi 2 nanowires grown on Si substrates have been studied extensively [1][2][3][4][5]8,9]. The lattice mismatch of the hexagonal type ErSi 2 in h0 0 0 1i direction (caxis) with Sih1 1 0i axis is 6.5%, and that between ErSi 2 h1 1 2 0i and Sih1 1 0i is À1.3%, respectively.…”

Atomic models for the ErSi2/Si(111) interface

“…Several growth techniques have been applied, especially for the system ErSi 2 /Si(111), which has been the most extensively studied [1][2][3][4][5][6][7]. Recently the growth of thin films or nanostructures of ErSi 2 on Si(100) has also been reported [8][9][10][11].…”