Measurement of reaction current during atomic force microscope local oxidation of conductive surfaces capped with insulating layers

A local oxidation technique using an atomic force microscope (AFM) was studied. The reaction current passing through the AFM tip was measured in order to evaluate its dependence on the resistivity and surface condition of the samples. The current efficiency actually contributing the oxidation reaction was about 0.5 for a Si substrate. The ratio was constant regardless of the tip scan speed. As for NiFe thin films, the current was higher and the current efficiency was lower than those of the Si substrate. The Al(2)O(3) capped layer on the NiFe thin films reduced the excess current, which did not contribute to the oxidation.