Microscopic four-point atomic force microscope probe technique for local electrical conductivity measurement

A micro-four-point probe technique for local electrical conductivity measurement is presented. An atomic force microscope (AFM) probe was fabricated into four parallel electrodes isolated from each other. Electrodes separated by a distance as small as 1.0 μm were used to perform the current and electrical potential measurements. This technique is a combination of the principles of the four-point probe method and standard AFM. The equipment is capable of simultaneously measuring both surface topography and local electrical conductivity. Experiments show the microprobe to be mechanically flexible and robust. The repeatable conductivity measurement on the submicron surface of thin aluminum and indium tin oxide films demonstrates the capability of the equipment and its possible extension to characterize microdevices and samples.