A high-resolution mixed field immersion lens attachment for conventional scanning electron microscopes

This article deals with a compact mixed field add-on lens attachment for conventional scanning electron microscopes (SEMs). By immersing the specimen in a mixed electric-magnetic field combination, the add-on lens is able to provide high image resolution at relatively low landing energies (<1 keV). Experimental results show that the add-on lens unit enables a tungsten gun SEM to acquire images with a resolution of better than 4 nm at a landing energy of 600 eV, which lies close to simulation predictions. Normally, this type of SEM would only be able to provide this kind of resolution at high voltages (30 kV). (C) 2002 American Institute of Physics.