Chromatic correction: a revolution in electron microscopy?

Abstract

When the development of correctors started in the 1970s, chromatic correction was already the main goal. The first corrector that could improve the resolution of an electron microscope was a chromatic corrector for a scanning electron microscope. Within the last three decades, the development of transmission electron microscopes (TEMs) was to a large extent driven by the attempt to improve the resolution in the presence of chromatic aberration. The major technical developments were high acceleration voltages, highly excited objective lenses with short focal length and field emission guns. Meanwhile, chromatic correction has reached the TEM world. Now, the question arises as to whether chromatic correction will make some of the aforementioned developments obsolete for high-resolution TEM, thereby opening up new imaging possibilities, which are nowadays prevented by instrument constraints. We show some examples for a 0.1 nm resolution TEM with unconventional microscope designs: very low voltages, far-field objective lenses and inexpensive electron guns.