A new aberration-corrected,energy-filtered LEEM/PEEM instrument. I. Principles and design |
| |
Authors: | RM Tromp JB Hannon AW Ellis W Wan A Berghaus O Schaff |
| |
Affiliation: | 1. IBM T.J. Watson Research Center, 1101 Kitchawan Road, P.O. Box 218, Yorktown Heights, NY 10598, USA;2. Ernest Orlando Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mailstop 80R0114, Berkeley, CA 94720, USA;3. SPECS GmbH, Voltastrasse 5, D-13355 Berlin, Germany |
| |
Abstract: | We describe a new design for an aberration-corrected low energy electron microscope (LEEM) and photo electron emission microscope (PEEM), equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control over the chromatic and spherical aberration coefficients Cc and C3, as well as the mirror focal length, to match and correct the aberrations of the objective lens. For LEEM (PEEM) the theoretical resolution is calculated to be ∼1.5 nm (∼4 nm). Unlike previous designs, this instrument makes use of two magnetic prism arrays to guide the electron beam from the sample to the electron mirror, removing chromatic dispersion in front of the mirror by symmetry. The aberration correction optics was retrofitted to an uncorrected instrument with a base resolution of 4.1 nm in LEEM. Initial results in LEEM show an improvement in resolution to ∼2 nm. |
| |
Keywords: | Low energy electron microscopy Photo electron emission microscopy Aberration correction Resolution |
本文献已被 ScienceDirect 等数据库收录! |
|