ELECTRON-OPTICAL DESIGN OF A HIGH-RESOLUTION LOW-VOLTAGE SCANNING ELECTRON-MICROSCOPE WITH FIELD-EMISSION GUN

In the present study, a comprehensive description and a complete proce ss for designing a high-resolution low-voltage scanning electron micro scope with a field emission gun have been discussed, including the des ign of two types of magnetic immersion lenses optimized for low-voltag e operation, the evaluation of their resolution, the design of the mag netic lens/secondary electron collector system, the calculation of thr ee-dimensional trajectories for both secondary electrons and backscatt ered electrons, and the estimate of their collection efficiency. The c omputed results and the primary experiments indicate the possibility o f achieving nanometer resolution, which basically approaches the elect ron optical predictable probe size for the low-voltage scanning electr on microscope.