Coalescence of magnetron-sputtered silver islands affected by transition metal seeding (Ni, Cr, Nb, Zr, Mo, W, Ta) and other parameters

Silver thin films were deposited on various base layers using magnetron sputtering. The onset of coalescence of silver islands was evaluated using in situ conductivity measurements. The substrates included glass and silicon, with base layers of ZnO:Al 4 at.% at various thickness and additional thin seed layers of transition metals. It is shown that certain conditions promote coalescence, and in particular the following seed conditions: tungsten (1.0 nm), molybdenum (0.1 nm), zirconium (0.5 nm), and nickel (0.1-0.2 nm). In the absence of transition metal seeding, earlier onset of coalescence occurred at the thinnest of the ZnO:Al 4 at.% base layers (5 nm) and the lowest sputtering power (50 W), indicating that the substrate-film system is not in thermodynamic equilibrium