Simulation Study of Auger Electron Emission Features in Tip-Sample Electric Field Region for Scanning Probe Electron Energy Spectrometer

A simulation study of the emission features of the Auger electrons in the electric field region localized within the cylindrical tip shield of a scanning probe electron energy spectrometer (SPEES) are reported. By taking into account synthetically the influence of every detailed factor, the relative intensity distributions for the outgoing Auger electrons are calculated by simulation. The results show that only those Auger electrons emitted from an annulus on sample surface with a width less than its radius can escape from the tip-sample electric field region. This provides a possible way for SPEES to improve the spatial resolution beyond the size of near-field emission electron beam from the tip. The distribution of the emission direction and the vertical height of the outgoing Auger electrons at the edge of the electric field have also been studied, revealing that most of the outgoing Auger electrons are parallel to the sample surface, and their vertical heights are constrained to a small range. These results are significant for improving the detection efficiency, the energy and spatial resolutions of the SPEES, and also provide instructive data for the designing of the tip shield and the electronic optical system in the tip-sample region for an SPEES. (C) 2009 The Japan Society of Applied Physics