STOPKA, Jan and Pieter KRUIT. Statistical Coulomb interactions in multi-beam SEM. INTERNATIONAL JOURNAL OF MODERN PHYSICS A. SINGAPORE: WORLD SCIENTIFIC PUBL CO PTE LTD, 2019, vol. 34, No 36, 11 pp. ISSN 0217-751X. Available from: https://dx.doi.org/10.1142/S0217751X19420211.
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Basic information
Original name Statistical Coulomb interactions in multi-beam SEM
Authors STOPKA, Jan and Pieter KRUIT.
Edition INTERNATIONAL JOURNAL OF MODERN PHYSICS A, SINGAPORE, WORLD SCIENTIFIC PUBL CO PTE LTD, 2019, 0217-751X.
Other information
Original language English
Type of outcome Article in a journal
Confidentiality degree is not subject to a state or trade secret
Impact factor Impact factor: 1.486
Doi http://dx.doi.org/10.1142/S0217751X19420211
UT WoS 000516718800022
Keywords in English Coulomb interactions; trajectory displacement; multi-beam SEM; electron optics; slice method
Tags RIV ne
Tags International impact, Reviewed
Changed by Changed by: Mgr. Jan Stopka, Ph.D., učo 409193. Changed: 20/7/2020 18:14.
Abstract
Statistical Coulomb interactions in conventional scanning electron microscopy mostly affect the probe size via energy spread and virtual source broadening in the emitter vicinity. However, in a multi-beam probe forming system such as a multi-beam scanning electron microscopes (MBSEM), the trajectory displacement due to interactions in the whole column can give a contribution to the final probe size. For single-beam systems, this can be expressed using approximate formulae for the total trajectory displacement in a beam segment (Jansen's theory) or by integrating contributions of infinitesimally thin beam slices (the slice method). We build on Jansen's theory of statistical Coulomb interactions and develop formulae for the trajectory displacement in a multi-beam system. We also develop a more precise semi-analytical result using the slice method. We compare both approaches with a Monte Carlo simulation and show a good agreement with the results of the slice method. Finally, we discuss the implications of our results for the optical design of multi-beam SEM. In a multi-beam with probe size dominated by Coulomb interactions, an increase in the number of beamlets does not necessarily provide an increase of throughput, because the probe size is limited by the total current. Furthermore, we disprove the notion of "the fewer the crossovers - the less the Coulomb interactions" by showing the quadratic dependence of trajectory displacement on segment length.
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