Spreading resistance imaging

Spreading resistance imaging depends on using a conductive AFM tip in direct contact with the sample surface [1].

A voltage bias is applied to the tip and the resulting current through the sample is measured as a function of the tip position on the surface simultaneously with acquisition topography in Constant Force mode.

It can easily be shown, assuming that the tip-surface contact resistance does not change with position, that the measured current for a given bias will be proportional to the local resistivity of sample under investigation.

Spreading resistance imaging can be also applied to samples with complicated structures, such as integrated circuits for example.

A review of current status of Spreading Resistance imaging is submitted in [2].

References

1. US Pat. 4992728.
2. J. Vac. Sci. Techn. B, 20 (1), 471 (2002).