TEM observation of the microstructure in sputtered NiFe/Au multilayer films

The cross-sectional nanostructure and plan-view structure of NiFe/Au multil ayer films (MLFs) were investigated using high-resolution electron microsco py (HREM). MLF series with different Au layer thicknesses, unseeded or with Cr or Cu buffer layers, were deposited on Si {100} wafers by magnetron spu ttering. The HREM images show that the Au layers have a strong {111} textur e along the film normal direction and dominate the crystallographic growth of the MLFs. Although the layer structure looks wavy near the grain boundar ies, the interfaces between the Au and NiFe layers are very flat - some ato mic steps and twins are visible. The difference in lattice parameters betwe en the NiFe and Au is taken up by misfit dislocations at the interfaces. Pl an-view images show the fee {111} lattice planes of NiFe and Au lying in th e plane of the layers. Thin buffer layers of Cr and Cu do not affect the cr ystal growth, but a thick Cu buffer (15 nm) disorders the {111} texture and the interface structure of the MLFs.