Thermodynamics and kinetics of room-temperature microstructural evolution in copper films

Abstract

We studied the energetics and kinetics of microstructural evolution in copper films by estimating the magnitude of various possible driving forces for microstructural change that can be present in the as-deposited film. A driving force of at least 100 J/cm3 is required to account for the speed at which the grain boundaries move at room temperature. This value cannot be accounted for by only considering the minimization of grain-boundary energy and possible effects related to surface and strain energy as the main driving mechanisms. It is suggested that the additional driving force which is needed to explain the speed at which the grains recrystallize, is originating from a high density of defects within the as-deposited grains.

Recrystallization of Electrodeposited Copper Thin Films During Annealing

“…6, the activation energy for Cu recrystallization is 0.93 eV, which compares well to the activation energy obtained from isothermal data. Furthermore, this activation energy is similar to that of grain boundary selfdiffusion in Cu (0.92 eV) 15 and agrees well with the work of Detavernier et al 5 (0.92 eV) and Cabral et al 16 (0.92 ± 0.19 eV) on 970-nm-thick Cu films.…”

“…There was a debate in the literature regarding whether this phenomenon can be described as grain growth, abnormal grain growth, or recrystallization. 1,5 This debate stems from the fact that the grains grow at a rate higher than expected at room temperature, which suggests that the driving pressure for self-annealing is not dominated by grain-boundary area reduction. From transmission electron microscopy (TEM) observations, self-annealing was found to be driven by stored energy in the form of dislocations and can thus be described as recrystallization.…”

Cu/Si(001) epitaxial growth: role of the epitaxial silicide formation in the structure and the morphology

“…It is explained by the presence of lot of defects (grain boundaries, dislocations, stacking faults, etc.) [17]. In the case of such observation during Cu growth, grain boundary energy minimization may be the main driving force.…”

Increasing the mean grain size in copper films and features

“…Recently, Rossnagel et al [103] and Bernat et al [104] showed that the resistivity in sputtered deposited copper films (with thickness below 100nm) descreases during storage after deposition. Detavernier et al observed self-annealing in sputtered deposited films up to 1500nm in thickness, and showed that the phenomenon is very dependent on the deposition parameters like the substrate temperature and sputter gas pressure and hence, on the microstructure of the as-deposited film [105][106]. In discussing the results, they used zone models to characterize the microstructure [107][108].…”