Ion induced adhesion via interfacial compounds

Strong, stable adhesion of Cu thin films deposited on Al2O3 (sapphire) can be obtained by presputtering the substrate surface with 500 eV Ar+ ions before deposition of copper. The existence of a well-defined optimum fluence of sputtering ions suggests that the interface atomic configuration can be optimized to favor the formation of Cu-Al-O chemical bonding. The existence of a ternary bonding environment is inferred independently from a new dominant peak in the XPS spectrum from interface copper, whose occurrence is correlated with the optimized adhesion conditions. © 1987 Elsevier Science Publishers B.V.