A high resolution scanning electron microscope collects secondary Auger electrons
through its objective lens to sensitively determine the chemical make-up with extremely
fine positional resolution. The system uses a magnetic high resolution objective
lens, such as a snorkel lens or a dual pole magnetic lens which provides an outstanding
primary electron beam performance. The Auger electrons are deflected from the path
of the primary beam by a transfer spherical capacitor. The primary beam is shielded,
by a tube or plates, as it traverses the spherical capacitor to prevent aberration
of the primary beam and the external wall of the shield maintains a potential gradient
related to that of the spherical capacitor to reduce aberration of the primary
electron beam. The coaxial configuration of the primary electron beam and the collected
secondary electron beam allows the Auger image to coincide with the SEM view.