Investigation of sputter-deposited Al-2at.%Cu layers by means of the tomographic atom probe (TAP)

Sputter-deposited Al-2at.%Cu layers have been investigated with respect to their microstructure and the spatial distribution of the elements using the tomographic atom probe. Al grains show columnar shape in the as-sputtered state, where the matrix is supersaturated with Cu. Upon annealing at temperatures between 150 and 350 °C, a significant decrease in the average Cu concentration is measured within the grains. Neither second phase formation within the Al matrix nor Cu enrichment at the surface or at the layer/substrate interface have been detected, suggesting segregation of Cu atoms in Al grain boundaries.