Structural evolution in annealing of layered C-Cu composite films

Thin carbon-copper layered films are sputtered using a dc magnetron unit. Transmission electron microscopy and electron diffraction are used to examine the structural evolution of the films in annealing at 600A degrees C in vacuum. Two types of films are examined: two-layer carbon-copper and three-layer carbon-copper-carbon films. In annealing, the copper layers disintegrate, ensembles of copper particles form, and diffusion coalescence of particles in the two-layer film is observed. Hence, the density of copper particles decreases and their ensemble-average size increases. The coalescence in the two-layer film is slower than that predicted by theory because of the actual microstructure of quasiamorphous carbon substrate film. In the three-layer film, no coalescence is observed because of the specific morphologic and structural features of copper particles and carbon layers.