Gun energy filter for a low energy electron microscope

Rudolf M Tromp; James B Hannon; Meredith L Dyck

doi:10.1016/j.ultramic.2023.113798

Gun energy filter for a low energy electron microscope

Ultramicroscopy. 2023 Nov:253:113798. doi: 10.1016/j.ultramic.2023.113798. Epub 2023 Jun 20.

Authors

Rudolf M Tromp¹, James B Hannon², Meredith L Dyck³

Affiliations

¹ IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598, United States. Electronic address: rtromp@us.ibm.com.
² IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598, United States.
³ Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, MD 20740, United States.

PMID: 37354876
DOI: 10.1016/j.ultramic.2023.113798

Abstract

In a Low Energy Electron Microscope (LEEM) the sample is illuminated with an electron beam with typical electron landing energies from 0-100 eV. The energy spread of the electron beam is determined by the characteristics of the electron source. For the two most commonly used electron sources, LaB₆ and cold field emission W, typical energy spreads ΔE are 0.75 and 0.25 eV at full width half maximum, respectively. Here we present a design for a LEEM gun energy filter, that reduces ΔE to ∼100 meV. Such a filter has been incorporated in the IBM/SPECS AC-LEEM system at IBM. Experimental results are presented and found to be in excellent agreement with expectations.

Keywords: Energy resolution; Gun energy filter; Low energy electron microscopy; Mirror electron microscopy.