Chapters authored
Inter-Diffusion of Nickel and Palladium with Germanium
Nickel and palladium germanides are the most promising candidates for nano-electronic contact materials to active areas of germanium-based devices. Solid-state reactions were thermally induced in conventional thin film couples of the Ni/Ge and Pd/Ge systems in order to study the sequence of phase formation. By embedding a thin layer of tantalum or tungsten as an inert marker between coupling thin film layers and observing its movement during phase formation, the dominant diffusing species were identified and monitored. In the Ni/Ge system, Ni5Ge3 was the first phase to form followed by NiGe. The results showed that during Ni5Ge3 formation, Ni was the sole diffusing species. During NiGe formation, both Ni and Ge diffused with the Ge diffusion prominent during the early stages, while the later stage of growth was dominated by Ni diffusion. The only phases observed to form in the Pd/Ge system were PdGe and Pd2Ge, the latter being the first. Palladium was the dominant diffusing species during both phase formations. Lateral diffusion couples were also prepared by the deposition of thick rectangular islands of germanium on to thin films of nickel and palladium. Several aspects of thermally induced lateral (as opposed to vertical) growth of phases were studied.
Part of the book: Intermetallic Compounds