Single pole-piece objective lens with electrostatic bipotential lens for SEM

Yonezawa, Akira; Maruo, Masayuki; Takeuchi, Toshitada; Morita, Seiji; Noguchi, Akiyoshi; Takaoka, Osamu; Sato, Mitsuyoshi; Wannberg, B.

doi:10.1093/jmicro/51.3.149

Cited by 9 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They compared two variants of the lens differing only slightly as regards the primary electron optics but exhibiting large differences in collection efficiency for 1 keV primary electrons. Yonezawa et al (2002) simulated signal trajectories in a single pole piece OL with an electrostatic bipotential lens for the landing energy around 1 keV. Extraction of SE in the immersion lens was studied also by Shao (1989).…”

Section: Introductionmentioning

confidence: 99%

Collection of secondary electrons in scanning electron microscopes

Müllerová

Konvalina

2009

Journal of Microscopy

View full text Add to dashboard Cite

SummaryCollection of the secondary electrons in the scanning electron microscope was simulated and the results have been experimentally verified for two types of the objective lens and three detection systems. The aberration coefficients of both objective lenses as well as maximum axial magnetic fields in the specimen region are presented. Compared are a standard side-attached secondary electron detector, in which only weak electrostatic and nearly no magnetic field influence the signal trajectories in the specimen vicinity, and the side-attached (lower) and upper detectors in an immersion system with weak electrostatic but strong magnetic field penetrating towards the specimen. The collection efficiency was calculated for all three detection systems and several working distances. The ability of detectors to attract secondary electron trajectories for various initial azimuthal and polar angles was calculated, too. According to expectations, the lower detector of an immersion system collects no secondary electrons I and II emitted from the specimen and only backscattered electrons and secondary electrons III form the final image. The upper detector of the immersion system exhibits nearly 100% collection efficiency decreasing, however, with the working distance, but the topographical contrast is regrettably suppressed in its image. The collection efficiency of the standard detector is low for short working distances but increases with the same, preserving strong topographical contrast.

show abstract

Section: Introductionmentioning

confidence: 99%

Collection of secondary electrons in scanning electron microscopes

Müllerová

Konvalina

2009

Journal of Microscopy

View full text Add to dashboard Cite

show abstract

“…The former are field emitters (FEs) such as Schottky or cold-field emitters (Schwind et al, 2006; Swanson & Schwind, 2009). The methods to achieve the latter include magnetic immersion lenses (or in-lenses) (Nagatani et al, 1986), beam-retarding via negative bias application to specimens (Yau et al, 1981), beam boosters (Frosien, 1989), and their combinations (Knell & Plies, 1999; Yonezawa et al, 2002). Considering standard electron-optical theory, advanced objective lenses place the principal plane closer to specimens through magnetic/electric field immersion, generating shorter focal lengths, reduced aberrations, and achieving higher resolution.…”

Section: Introductionmentioning

confidence: 99%

A Novel Monochromator with Offset Cylindrical Lenses and Its Application to a Low-Voltage Scanning Electron Microscope

et al. 2022

View full text Add to dashboard Cite

Low-voltage scanning electron microscopes (LV-SEMs) are widely used in nanoscience. However, image resolution for SEMs is restricted by chromatic aberration due to energy spread of the electron beam at low acceleration voltage. This study introduces a new monochromator (MC) with offset cylindrical lenses (CLs) as one solution for LV-SEMs. The MC optics, with highly excited CLs in offset layouts, has advantageous high performance and simple experimental setup, making it suitable for field emission LV-SEMs. In a preliminary evaluation, our MC reduced the energy spread from 770 to 67 meV. The MC was integrated into a commercial SEM equipped with an out-lens (a conventional objective lens without immersion magnetic or retarding electric fields) and an Everhart–Thornley detector. Comparing SEM images under two conditions with the MC turned on or off, the spatial resolution was improved by 58% at 0.5 and 1 keV. The filtering effect of the MC decreased the probe current with a ratio (i.e., transmittance) of 5.7%, which was consistent with estimations based on measured energy spreads. To the best of our knowledge, this is the first report on an effective MC with higher-energy resolution than 100 meV and the results offer encouraging prospects for LV-SEM technology.

show abstract

“…To improve image resolution, several modifications of components of SEM systems have been adopted, such as the use of the immersion objective lens, the compound object lens superimposed with electrostatic and magnetic field objective lens, and the retarding field objective lens. [1][2][3][4][5][6][7][8] These lenses reduce spherical and chromatic aberrations drastically, especially at lower accelerating voltages of less than 2 keV. However, systems for detecting secondary electrons (SEs) are more complex because the magnetic and electrostatic fields change energies and angles of emitted SEs depending on electron optics conditions such as accelerating voltage and working distance.…”

Section: Introductionmentioning

confidence: 99%

Development of a fountain detector for spectroscopy of secondary electrons in scanning electron microscopy

Agemura¹,

Kimura²,

Sekiguchi³

2018

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

The low-pass secondary electron (SE) detector, the so-called “fountain detector (FD)”, for scanning electron microscopy has high potential for application to the imaging of low-energy SEs. Low-energy SE imaging may be used for detecting the surface potential variations of a specimen. However, the detected SEs include a certain fraction of tertiary electrons (SE3s) because some of the high-energy backscattered electrons hit the grid to yield SE3s. We have overcome this difficulty by increasing the aperture ratio of the bias and ground grids and using the lock-in technique, in which the AC field with the DC offset was applied on the bias grid. The energy-filtered SE images of a 4H-SiC p–n junction show complex behavior according to the grid bias. These observations are clearly explained by the variations of Auger spectra across the p–n junction. The filtered SE images taken with the FD can be applied to observing the surface potential variation of specimens.

show abstract

Single pole-piece objective lens with electrostatic bipotential lens for SEM

Cited by 9 publications

References 0 publications

Collection of secondary electrons in scanning electron microscopes

Collection of secondary electrons in scanning electron microscopes

A Novel Monochromator with Offset Cylindrical Lenses and Its Application to a Low-Voltage Scanning Electron Microscope

Development of a fountain detector for spectroscopy of secondary electrons in scanning electron microscopy

Contact Info

Product

Resources

About