Cross-sectional characterization of the dewetting of a Au/Ni bilayer film.
The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO2/Si interface structure, the majority of the metal/SiO2interface was Au/SiO2after annealing at 675°C for 1h. Void nucleation was predominantly observed at Au/Ni/SiO2triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO2interface sections is found to be energetically preferred over Ni/SiO2due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect.
Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, United States.
Xi
X
Cen
Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, United States.
Andrew M
AM
Thron
Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, United States.
Xinming
X
Zhang
Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, United States.
Klaus
K
van Benthem
Dewetting; Gold/nickel bilayer film; Void formation