ABSTRACT
Since the famous picture of Ogura1, it is known that high-resolution Back Scattered Electron (BSE) images can be obtained in a Field Emission Scanning Electron Microscope (FE-SEM) at the nanometer level. Since then, there have been some new ideas about the contrast and resolution mechanisms of BSE images in the FE-SEM2. Even if thousands of high-resolution BSE pictures have been taken since in the FE-SEM, there is still a need of an explanation of the contrast and resolution mechanisms of high resolution BSE images in the FE-SEM. In order to do so, a new Monte Carlo program have been developed to simulate BSE images in multilayered structures. Several line scans have been simulated for AlAs layers of various widths embedded in GaAs for various beam energies. For each run, 5000 electron trajectories have been simulated. The beam size has been assumed to decrease linearly from 2.5 nm at 1 keV to 1 nm at 15 keV and to remain to this value for greater beam energy.
