Miniature electron-optical columns

Miniaturized electron-optical systems based on a field emission microsource and a microlens for probe forming have been studied. The performance of systems with dimensions (length and diameter) in the submillimeter to millimeter range can exceed that of a conventional system over a wide range of potentials (100 V to 10 kV) and working distances (up to 10 mm). Electron-optical studies show that not only can a significant reduction in size be achieved but the performance in terms of resolution and especially beam current can also be greatly improved. A key component of the miniaturized system is the field emission microsource which provides an improvement of two to three orders of magnitude in effective brightness over the conventional field emission source. Among the options, the STM aligned field emission (SAFE) microsource appears most promising and a selective scaling approach has been developed to allow this source to operate over a wide range of potentials. Preliminary experimental studies of the microsource have been conducted