Influence of electron flux on the oxidation of Ni3Al surfaces

Abstract

Electron beam currents of a few nanoamps, currently used in nanometer scale scanning Auger microscopy scanning electron microscopy, promote oxidation of polycrystalline Ni 3 Al to a degree that depends on the size of the beam and subsequently on the electron flux e . In fact, the oxidation of Ni 3 Al at room temperature follows a model based on the premise that the electron beam creates additional nucleation sites around which oxide growth occurs. With increasing beam size the oxidation process becomes slower and O chemisorption plays a significant role. As a result the Ni-oxide depth decreases drastically with an increasing spot size ͑or equivalently decreasing electron flux͒. It offers an alternative way to monitor the NiO thickness in the nanometer range.