Interfacial Diffusion

Abstract

The current understanding of mass transport at interfaces in solids is reviewed.The materials covered are metals, semiconductors and ionic compounds and the interfaces are mainly grain boundaries.In metals and semiconductors grain boundary diffusion is always faster than the bulk and both experiments and theory support the concept of narrow (about 1 nm) pathways in which fast diffusion occurs by a point defect mechanism.In ionic compounds, however, experiments have indicated that in some materials grain boundary diffusion is faster in the bulk whereas in others it is slower. Furthermore, different workers have reached different conclusions in, ostensibly, the same materials. The possible reasons for this lack of convergence are discussed.

The Diffusion Mechanism of Ge During Oxidation of Si/SiGe Nanofins

“…We have shown that strain and enhanced Ge content alone cannot account for this enhancement in vertical Ge diffusivity, and therefore, we propose that Ge is diffusing along the Si/SiO 2 interface, followed by a reinsertion process. It is well-known that interfacial and grain boundary diffusion can be much faster than bulk diffusion . For example, arsenic diffusivity along polycrystalline Si grain boundaries has been found to be up to 4 orders of magnitude greater than in single-crystal Si .…”

“…It is wellknown that interfacial and grain boundary diffusion can be much faster than bulk diffusion. 42 For example, arsenic diffusivity along polycrystalline Si grain boundaries has been found to be up to 4 orders of magnitude greater than in singlecrystal Si. 43 In this case, the grain-boundary interface is between regions of the same material, Si.…”