Improved focusing-and-deflection columns

P. H. Mui, M. Szilagyi

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


Our earlier design procedures for constructing quadrupole columns are further expanded to include octupole corrector units and 'octupole' deflectors with no third-order harmonics. The additional complications are finer partitioning of the plates and increased number of voltage controllers. Two sample designs, one having only the additional octupole deflectors and one having both the deflectors and the correctors, are presented and compared to our previous quadrupole system. The additional octupole components are shown to be capable of increasing the current density from 30% to more than 300% for a four-plate system, designed to focus and scan the electron beam over a circular area of 0.25 mm radius. The electron beam is assumed to have an initial divergence of ±2.3 mrad, an initial energy of 6 kV, a total energy spread of 1 eV, and a final acceleration of 30 keV. These systems are then slightly reoptimized for a superficial comparison with the commercially available column by Micrion Corporation. The numerical results indicate a potential for substantial improvements, demonstrating the power of this design procedure. Finally, a discussion is presented on how the individual components can interact with each other to reduce the various aberrations.

Original languageEnglish (US)
Pages (from-to)1496-1507
Number of pages12
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number4
StatePublished - Jul 1995
EventProceedings of the 22nd Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI-22) - Scottsdale, AZ, USA
Duration: Jan 8 1995Jan 12 1995

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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