Forces in the tunneling contact

The processes of silicon surface oxidation in the tunneling contact have been studied. As the sample is oxidized, significant changes in the dependences of the tunneling current on the needle-sample distance have been observed alongside with changes in the relief of the tunneling images of oxidized regions (the occurrence of hollows with the depth from tens to hundreds of nanometers). To interpret the data, a model of conductivity of the oxidized silicon surface has been proposed. It includes a force interaction between the SEM probe and the specimen surface in the scanning process. The forces acting in the tunneling contact have been estimated within the Hertz model of elastic contact strains. Their values have been found to be in the range of 10 -4-10-5 N.