A high signal-to-noise ratio toroidal electron spectrometer for the SEM

Hoang, Hung Quang; Osterberg, Mans; Khursheed, Anjam

doi:10.1016/j.ultramic.2011.06.003

Cited by 18 publications

(16 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This happens because, as the specimen becomes more negative, low energy secondaries are deflected upwards by accelerating sample fields, causing some electrons to be pulled away from the analyzer entrance slit, as illustrated in Figure 1b, and some (smaller angle) electrons, to be pulled into the analyzer. These analyzer signals are very different than the ones obtained for V S = V C1 (field free region above the specimen), as shown in Figure 2b, where the SE analyzer signal shifts to the right, but grows significantly in height, similar to the results reported previously by Hoang et al (2011). This is because these electrons go into the analyzer at steeper entrance angles than the previous ones (absence of specimen fields), and they as a result, strike the analyzer deflector plates, and do not contribute to the SE signal output.…”

Section: Experimental Analyzer Se Signals In Presence Of Specimen Fieldssupporting

confidence: 87%

“…The Rau and Robinson toroidal analyzer has first-order focusing charcteristics and requires multi-channel detection in the azimuthal angular direction. Initial results from a prototype of this analyzer were reported subsequently by Hoang et al (2011), demonstrating that the analyzer has an inherently high signal-to-noise capability, able to detect specimen voltage changes well into the sub-mV region. Initial results from a prototype of this analyzer were reported subsequently by Hoang et al (2011), demonstrating that the analyzer has an inherently high signal-to-noise capability, able to detect specimen voltage changes well into the sub-mV region.…”

Section: Introductionmentioning

confidence: 99%

“…Initial results from a prototype of this analyzer were reported subsequently by Hoang et al (2011), demonstrating that the analyzer has an inherently high signal-to-noise capability, able to detect specimen voltage changes well into the sub-mV region. It is the same setup reported by Hoang et al (2011) except that the specimen holder, which also supports entrance electrodes for the analyzer, is modified from the previous inner/outer cap hemispherical arrangement to be a concentric conical structure in which the specimen and inner/ outer caps can be independently biased. For more realistic specimens, a variety of different electric fields exist at the specimen surface and in the region below the analyzer entrance, and they will significantly change the form of the SE analyzer's output signals.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Voltage and Dopant Concentration Measurements of Semiconductors using a Band-Pass Toroidal Energy Analyzer Inside a Scanning Electron Microscope

Srinivasan

Khursheed

2015

Microsc Microanal

View full text Add to dashboard Cite

This paper presents experimental results obtained from a scanning electron microscope (SEM) second-order focusing toroidal electron energy analyzer attachment. The results demonstrate that the analyzer can be used to obtain high signal-to-noise voltage and dopant concentration measurements on semiconductors in the presence of different electric field conditions at the sample. The experimentally calculated relative error of measurement typically varies from 31 to 63, corresponding to secondary electron (SE) signal mean shifts of 9-18 mV. The millivolt accuracy of these results is over one order of magnitude better than earlier quantitative dopant concentration measurements made by a retarding field analyzer.

show abstract

Section: Experimental Analyzer Se Signals In Presence Of Specimen Fieldssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Voltage and Dopant Concentration Measurements of Semiconductors using a Band-Pass Toroidal Energy Analyzer Inside a Scanning Electron Microscope

Srinivasan

Khursheed

2015

Microsc Microanal

View full text Add to dashboard Cite

show abstract

“…The SE energy filtering in SEM has been widely used for many applications. In general, this method can be used as a technique for spectroscopy of low-energy secondary electrons emitted from many different materials [6,7] and for observing atomically thin films on metal substrates [8].…”

Section: Introductionmentioning

confidence: 99%

In-Lens Band-Pass Filter for Secondary Electrons in Ultrahigh Resolution SEM

et al. 2019

View full text Add to dashboard Cite

Scanning electron microscopes come equipped with different types of detectors for the collection of signal electrons emitted from samples. In-lens detection systems mostly consist of several auxiliary electrodes that help electrons to travel in a direction towards the detector. This paper aims to show that a through-the-lens detector in a commercial electron microscope Magellan 400 FEG can, under specific conditions, work as an energy band-pass filter of secondary electrons that are excited by the primary beam electrons. The band-pass filter properties verify extensive simulations of secondary and backscattered electrons in a precision 3D model of a microscope. A unique test sample demonstrates the effects of the band-pass filter on final image and contrast with chromium and silver stripes on a silicon substrate, manufactured by a combination of e-beam lithography, wet etching, and lift-off technique. The ray tracing of signal electrons in a detector model predicate that the through-the-lens detector works as a band-pass filter of the secondary electrons with an energy window of about 3 eV. By moving the energy window along the secondary electron energy spectrum curve of the analyzed material, we select the energy of the secondary electrons to be detected. Energy filtration brings a change in contrast in the image as well as displaying details that are not otherwise visible.

show abstract

“…Hoang et al recently reported a way to further enhance the signal-to-noise performance of the toroidal SE energy analyzer [13]. This technique is based upon creating an acceleration field at the entrance of the analyzer, which acts to pull in wider angle low energy secondaries into the analyzer.…”

mentioning

confidence: 99%

Energy Analyzer Attachments for the Scanning Electron Microscope

Khursheed

2015

Microsc Microanal

Self Cite

View full text Add to dashboard Cite

The Scanning Electron Microscope (SEM) is a high resolution imaging instrument, indispensable to research and development in Nano Science and Nano Technology. By integrating electron energy analyzers into its specimen chamber, it has the potential to become a powerful analytical tool that can map material science information on the Nano-Scale. This paper will review some selected aspects of research work aimed at developing electron energy analyzers attachments for the SEM. One of the most important requirements for energy analyzer attachments in the SEM is that they must be small. Figure 1a is a schematic diagram illustrating the limited space around the specimen. The distance between the final lens lower pole-piece and the specimen, the working distance, usually ranges between 3 to 20 mm, and for high resolution, it should be as small as possible. This means that the analyzer attachment height should typically be less than 20 mm. Another important requirement for the analyzer is that it should have a wide angular range of collection and detection, since the scattered electrons from the specimen travel back in all directions. Ideally, the analyzer should have a 2π radian azimuthal angle collection/detection range. The analyzer's ability to accept and detect electrons emitted over a wide range of angles is the main factor which limits its transport efficiency, which in turn, determines how short its data-acquisition times can be.

show abstract

A high signal-to-noise ratio toroidal electron spectrometer for the SEM

Cited by 18 publications

References 10 publications

Voltage and Dopant Concentration Measurements of Semiconductors using a Band-Pass Toroidal Energy Analyzer Inside a Scanning Electron Microscope

Voltage and Dopant Concentration Measurements of Semiconductors using a Band-Pass Toroidal Energy Analyzer Inside a Scanning Electron Microscope

In-Lens Band-Pass Filter for Secondary Electrons in Ultrahigh Resolution SEM

Energy Analyzer Attachments for the Scanning Electron Microscope

Contact Info

Product

Resources

About