Compositional Mapping of Metal Films by Friction Force Microscopy and Force Modulation Methods

Abstract

The characterization of metallic electrodes in semiconducting devices with high spacial resolution has become increasingly important. Scanning force microscopy (SFM) enables us to observe surface topographies on a nanometer scale as well as local mechanical properties such as friction force without any spacial surface treatment, while it is difficult to obtain high resolution with the conventional methods such as static time of flight-secondary ion mass spectroscopy and Auger electron spectroscopy because of their beam size. Here we have demonstrated the possibility of two dimensional mapping of the mechanical properties by friction force microscopy (FFM) and force modulation method (FMM) for Gold islands deposited on Nickel flat substrate. The FFM observation revealed that the grain size of the metallic islands ranged from 5 to 7000 nm. The friction force measurement showed that the friction force on Au islands was lower than the Ni substrate. The compositional high resolution mapping of metal films was obtained by FFM. In addition to the local mechanical measurement, FMM also showed the difference in stiffness between two materials.