Beyond conventional secondary electron imaging using spectromicroscopy and its applications in dopant profiling

Han, Weiding; Srinivasan, Anand; Banerjee, Amartya; Chew, Michael Yit Lin; Khursheed, Anjam

doi:10.1016/j.mtadv.2019.100012

Cited by 6 publications

(11 citation statements)

References 31 publications

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“…Figure 5c indicates that as the level of contamination increases, the overall height of the spectral signal falls. This is consistent with other investigations of contamination effects inside the SEM 46,59,60 . However, the form of the spectral signal also changes, as indicated in Fig.…”

Section: Resultssupporting

confidence: 93%

“…The NRMSD seems to vary logarithmically as a function of increasing levels of contamination (number of spectra per irradiated area). This is in agreement with prior investigations that monitored changes in shape of the SE energy spectral signal as levels of contamination were increased on doped Si samples 46 . It indicates that there is a fast contamination layer rate of growth initially, but it then subsequently slows down.…”

Section: Resultssupporting

confidence: 93%

“…Figure 5f quantifies the effects of shot noise by monitoring how the NRMSD changes as a function of the number of spectra used in the final averaging procedure. These results are consistent with prior experience of the role of shot noise in the SEM, both for SE imaging and SE spectral acquisition, where shot noise signal-to-noise ratio (SNR) have been observed to follow 1/√N Poisson/Normal distribution statistics 46,61,62 . The corresponding shot noise effects for Al and Si are presented in Supplementary Fig.…”

Section: Resultssupporting

confidence: 90%

“…The technique was previously reported as a means of improving the analyser output signal-to-noise ratio, and making the SE peak narrower and more symmetric. It was used to enhance dopant contrast and surface/trapped charge contrast [45][46][47][48] . Figure 1e,f demonstrate how biasing the specimen and its surrounding electrode by − 10 V in this context is similarly capable of enhancing material contrast information at a primary beam voltage of 1 kV, causing the negatively biased Au spectral signal height to be greater than the one for Pt, while making the Pt spectral signal broader than the Au spectral signal, overcoming the inconsistent results of the unbiased case shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The work reported here utilises a small wide-angle electric toroidal energy analyser SEM attachment design 29 , which has formerly been used to track small changes in the SE energy spectral signal shape for applications such as quantifying dopant concentration 45,46 and mapping interface/surface charge distributions 47,48 . It is used here to perform quantitative material analysis in a variety of different ways.…”

mentioning

confidence: 99%

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Quantitative material analysis using secondary electron energy spectromicroscopy

Han

Zheng

Banerjee

et al. 2020

Sci Rep

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This paper demonstrates how secondary electron energy spectroscopy (SEES) performed inside a scanning electron microscope (SEM) can be used to map sample atomic number and acquire bulk valence band density of states (DOS) information at low primary beam voltages. The technique uses an electron energy analyser attachment to detect small changes in the shape of the scattered secondary electron (SE) spectrum and extract out fine structure features from it. Close agreement between experimental and theoretical bulk valance band DOS distributions was obtained for six different test samples, where the normalised root mean square deviation ranged from 2.7 to 6.7%. High accuracy levels of this kind do not appear to have been reported before. The results presented in this paper point towards SEES becoming a quantitative material analysis companion tool for low voltage scanning electron microscopy (LVSEM) and providing new applications for Scanning Auger Microscopy (SAM) instruments.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Quantitative material analysis using secondary electron energy spectromicroscopy

Han

Zheng

Banerjee

et al. 2020

Sci Rep

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Characterization of materials using the secondary electron energy spectromicroscopy technique

Srinivasan¹,

Han²,

Zheng³

et al. 2021

Optical Materials: X

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Optimized dopant imaging for GaN by a scanning electron microscopy

Ban

Yuan

Huang

2023

Journal of Microscopy

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Two-dimensional dopant profiling is vital for the modelling, design, diagnosis and performance improvement of semiconductor devices and related research and development. Scanning electron microscopy (SEM) has shown great potential for dopant profiling. In this study, the effects of secondary electron (SE) detectors and imaging parameters on the contrast imaging of multilayered p-n and p-i junction GaN specimens via SEM were studied to enable dopant profiling. The doping contrast of the image captured by the in-lens detector was superior to that of the image captured by the side-attached Everhart-Thornley detector at lower acceleration voltages (V acc ) and small working distances (WD). Furthermore, the doping contrast levels of the in-lens detector-obtained image under different combinations of V acc and WD were studied, and the underlying mechanism was explored according to local external fields and the refraction effect. The difference in the angular distributions of SEs emitted from different regions, the response of the three types of SEs to detectors, and the solid angles of detectors toward the specimen surface considerably influenced the results. This systematic study will enable the full exploitation of SEM for accurate dopant profiling, improve the analysis of the doping contrast mechanism, and further improve doping contrast for semiconductors.

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Beyond conventional secondary electron imaging using spectromicroscopy and its applications in dopant profiling

Cited by 6 publications

References 31 publications

Quantitative material analysis using secondary electron energy spectromicroscopy

Quantitative material analysis using secondary electron energy spectromicroscopy

Characterization of materials using the secondary electron energy spectromicroscopy technique

Optimized dopant imaging for GaN by a scanning electron microscopy

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