High-resolution transmission electron microscopy of phase formation and growth in metal–Si–Ge systems

Enhanced growth of low-resistivity NiSi on epitaxial Si0.7Ge0.3 on (001)Si with a sacrificial amorphous Si interlayer

“…Ni(Si 0.9 Ge 0.1 ) islands were observed to form everywhere in 700°C annealed samples. 12 Figure 2 shows the GIXRD spectra for Ni(15 nm)/a-Si(27 nm)/Si 0.7 Ge 0.3 samples annealed at 300-800°C. Low-resistivity NiSi was found to be the only phase present in all samples annealed at above 500°C.…”

High-resolution transmission electron microscopy of silicide formation and morphology development of Ni/Si and Ni/Si1−xGex

“…No Ge was found anywhere close to regions III and VI or in their immediate interfacial regions, whereas region V has a Ge concentration as high as 25%. If it is assumed that Ni(Si 1-x Ge x ) crystals nucleate at the surface and grow through fast lattice diffusion, as NiSi 2 does in the Ni/Si system, the expelled Ge would be expected to accumulate rather uniformly along the entire hemispherical interface, a phenomenon reported as Ge "lacing" by Chen et al 12 This is because Ge is expected to be the slow diffusing species in the Ni/Si 0.8 Ge 0.2 system. During a rapid anneal, the slow-diffusing Ge would not have time to cluster and would be observed all along the boundary of the crystal.…”

“…Island structures and Ge segregation have been observed following high-temperature annealing treatments. [11][12][13] The failure of the Ni/Si 1-x Ge x system to form a uniform, low-resistivity silicide was ascribed to the higher heat of formation of Ni-Si compared to that for Ni-Ge, but little has been reported on the growth mechanisms and microstructural development of nickel germanosilicide.…”

Interplay Between Grain Boundary Grooving, Stress, and Dealloying in the Agglomeration of NiSi[sub 1−x]Ge[sub x] Films

“…Although the possible importance of this phenomenon has not previously been emphasized, polygonal NiSi 1−x Ge x interface morphologies can also be observed in earlier studies. 5,6,9,11 On the other hand, the NiSi/Si and NiGe/Ge interfaces appear to be much smoother curves (i.e., of nearly constant curvature), as shown by Figs. 2(b) and 2(c).…”