O. Schneegans et al., STUDY OF THE LOCAL ELECTRICAL-PROPERTIES OF METAL-SURFACES USING AN AFM WITH A CONDUCTING PROBE, IEEE transactions on components, packaging, and manufacturing technology. Part A, 21(1), 1998, pp. 76-81
The performances of coating materials for electrical contact elements
are more and more often investigated through various means. We report
here a new method we have developed for a few years in our lab, which
consists in performing localized resistance measurements over a surfac
e by means of an atomic force microscope (AFM) with a conducting probe
. This technique enables us to simultaneously obtain a cartography of
the surface roughness and of the local conductance within a given micr
oscopic area of a sample with nanometer scale resolution. Although the
elaboration of suitable probes remains an open problem, some convinci
ng images of metal surfaces have already been obtained, revealing occa
sionally surprising features. It can be observed for instance that the
local resistance values can vary; of several orders of magnitude betw
een two adjacent grains. Calculations performed from the measurements
allow to clarify the mechanical nature of the tip/surface nanocontact
and hence to determine the most probable transport process according t
o the range of resistance considered.