The field emission scanning electron microscope is configured similarly to a conventional scanning electron microscope, except that a field emission electron source is used, allowing higher resolution imaging, increased signal to noise ratio, and increased depth of field. A field emission electron source produces electrons by applying a high voltage to a very sharp point and extracting the electrons directly and only from the point. The coherence and very small diameter of this source increases the useful magnification of the SEM by a factor of ten.
