SOME APPROACHES TO LOW-VOLTAGE SCANNING ELECTRON-MICROSCOPY

The advantages of the low-energy electrons for surface study and different approaches to the design of low-voltage scanning electron microscope are briefly summarized. The retarding electrostatic field optics in front of a final cross-over image was reviewed to learn as much as possible about this optical element and to show how many people took care about this system. We used this optical element in a new combination, as a cathode lens immersed in the magnetic field of the single-polepiece lens, to achieve higher resolution at low landing energies and to get new possibilities in the detection system. We did a review of our work on this subject during the past year and point out our troubles in achieving theoretical resolution of 25 nm at 10 eV.