At the same time, agglomeration results in a loss of configurational entropy. These two competing effects control the nucleation of vacancy clusters. Voids or cavities are stabilized by the presence of gases, either because they passivate the surface or provide internal pressure. This is a well known phenomenon in radiation damage, where the gas is often helium. Diffusion in Silicon Figure 1 is an Arrhenius plot of the tracer diffusivity of many elements in Si, as well as the self-diffusivity.
Copper has the highest diffusivity over the entire temperature range.
Some representative values are listed in Table I. As with Au, Li, Ni and Fe, the high diffusivity of Cu is the result of its atoms moving interstitially through the silicon lattice. I show the equilibrium solubility of Cu as a function of temperature. Self- and impurity diffusivities in silicon. After Frank, et al. Solubility of copper in silicon.