Reaction of ultrathin Co layers with Si(111) and Si(100) surfaces

Co growth on Si(001) and Si(111) surfaces: Interfacial interaction and growth dynamics

“…Our results for clean surfaces thus agree with previous work described in Refs. [4][5][6][9][10][11][12][13]. It is known that hydrogen desorption from the Si surface is only significant above 300°C, and that the Si-H bond is particularly strong with a bond energy of 3.5 eV compared to the Si-Si bond energy of 2.3 eV [38].…”

“…Unlike previous work described in Refs. [4][5][6][9][10][11][12][13] for the growth of Co films on clean surfaces, the growth of Co on H-terminated surface does not occur by either growth of Co-Si mixture in a layer-by-layer mode or via formation of a Co-Si solid solution with inter-diffusion of Co and Si atoms.…”

“…Unlike growth on Si(1 1 1), both Rangelov et al [5] and Meyerheim et al [7] did not observe spontaneous formation of CoSi 2 . Instead, there are four deposition regimes depending on the Co coverage [7].…”

“…When more than 5 ML Co is deposited, the surface becomes more cobalt rich than the initial CoSi 2 phase. According to Rangelov et al [5], as Co coverage increases, part of the Co atoms exist in a CoSi 2 -like environment while the rest forms a Co-Si solid solution with inter-diffusion of Co and Si atoms. Using low energy electron diffraction (LEED) and XPS, Derrien et al [6] found that when the Co coverage exceeds 2.0 ML, the LEED spot associated with Si(1 1 1)-(7 · 7) disappears and a Si(1 1 1)-(1 · 1) pattern forms.…”

Growth of magnetic tunnel junctions on Si(001) substrates

“…Even for room temperature deposition, interface silicides can formed. For example, in the case of Co deposition on Si, it has been shown by many groups [12][13][14][15][16][17] that for sub-monolayer of Co deposition, Co reacts with Si to form the CoSi 2 phase even at room temperature. When the Co coverage increases, the deposited film becomes less and less rich in Si and a pure Co layer can be formed after the deposition of about 4-5 ML.…”