Agglomeration of Copper Thin Film in Cu/Ta/Si Structure

Abstract

Copper agglomeration in Cu(100 nm)/Ta(50 nm)/Si structure deposited by ion beam deposition was examined. Copper thin films were annealed at 650 C for 1 to 60 min in hydrogen atmosphere. The surface morphology, crystalline microstructure and electrical resistivity were investigated by field-emission scanning electron microscopy, X-ray diffraction and Van der Pauw method, respectively. Experimental results revealed that nucleation and growth of voids ocurred in the copper film annealed for 5 min. Further annealing made the film a connected island structure and then isolated island structure.

Metallic Copper Thin Films Grown by Plasma‐Enhanced Atomic Layer Deposition of Air Stable Precursors

“…The large surface energy of the copper atoms, creates thermal activation in order to minimize the free energy by surface rearrangement . It has been shown, that after chemisorption onto the surface OH‐groups, diffusion of the initial copper nuclei takes place to form agglomerates .…”

Thermal Atomic Layer Etching of Copper by Sequential Steps Involving Oxidation and Exposure to Hexafluoroacetylacetone

“…27 When the copper film is thin (<15nm) (Figure 4c), a pronounced morphology change and dewetting occurs when the film is oxidized with molecular oxygen and etched with Hhfac in several cycles (Figures 4d). It is well known that a copper film will tend to dewet when a pinhole exposes the substrate surface, and that this effect is stronger in the presence of adsorbed oxygen, e.g., on SiO 2 , 27 W(100), 28 and Ta 29,30 substrates. It is possible that a similar dewetting instability occurs for copper on air-exposed ruthenium.…”

Comparison of Cu and Pt point-contact electrodes on proton conducting BaZr0.7Ce0.2Y0.1O3−

“…Cu is a transition metal with unusually high mobility at elevated temperatures, and in order to use Cu as an electrode for applications with proton-conducting electrolytes, this effect must be mitigated. To suppress coarsening, other researchers have combined Cu with materials such as Ta, Cr and Co [68,70,123,124]. Of these, Co seems to be the most successful, and was thus used in this work.…”