A spectroscopic scanning electron microscope design

Abstract

Summary: This paper describes a proposal to improve the design of scanning electron microscopes (SEMs). The design is based upon using an SEM column similar to the conventional one, magnetic sector plates and a mixed field immersion objective lens. The optical axis of the SEM column lies in the horizontal direction and the primary beam is turned through 90 degrees before it reaches the specimen. This arrangement allows for the efficient collection, detection and spectral analysis of the scattered electrons on a hemispherical surface that is located well away from the rest of the SEM column. The proposed SEM design can also be easily extended to incorporate time multiplexed columns and multi-column arrays.

Developments in the design of a spectroscopic scanning electron microscope

“…In the previous spectroscopic SEM proposal made by the present authors [5], a square magnetic sector unit was proposed, based upon its success reported for the low energy electron microscope (LEEM) by Tromp et al [7]. However, the present work shows that in the context of the spectroscopic SEM design, a circular sector unit is more suitable.…”

“…For the previous spectroscopic SEM design by the present authors [5], in order to achieve low aberrations and operate with stigmatic focusing conditions, it was assumed that the sector's outer plate excitation should be around three times greater than the inner plate excitation, have the same sign, and that the incoming primary beam should project a focus point into the centre of the sector unit. These operating conditions were reported by Tromp et al for LEEM [7].…”

“…Simulation results presented in this paper predict that first-order focusing at the detector plane can be achieved and that the SEM will also be able to acquire nano-meter resolution images at low landing voltages (less than 1 kV). The work reported here follows on naturally from the ''Spectroscopic SEM'' proposal previously made by the present authors [5]. In this paper, the design is further simulated and developed.…”

Redesign of the scanning electron microscope for parallel energy spectral acquisition

“…Recently, a ''Spectroscopic scanning electron microscope (SEM)'' proposal made by Khursheed et al [1,2] describes the possibility of redesigning the SEM so that it can capture the entire energy range of scattered electrons that leave the specimen. The new design, depicted in Fig.…”

Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images

“…This understanding informed the design of the low-energy electron microscope (LEEM) [ 10 , 11 ]. LEEM has supported complex studies in materials science [ 12 – 15 ]. However, in LEEM, the sample is generally irradiated with a flood beam and uses complex instrumentation of magnetic sector plates to separate electrons leaving the sample from the primary beam.…”