Temperature dependence of secondary electron emission: A new route to nanoscale temperature measurement using scanning electron microscopy

Khan, M. Iltaf; Lubner, Sean; Ogletree, D. Frank; Dames, Chris

doi:10.1063/1.5050250

Cited by 12 publications

(9 citation statements)

References 24 publications

(34 reference statements)

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“…Comparing heating by the e-beam versus Joule heating of a PRT, the e-beam heating approach offers several advantages. First, although the e-beam based k -measurements in this study required additional microfabrication to create the PRT, in principle the temperature could instead be measured directly using the SEM , or TEM − itself. This will greatly simplify the microfabrication and facilitate the e-beam heating and sensing at arbitrary locations and with various shapes.…”

Section: Resultsmentioning

confidence: 99%

“…In this work, we have found the MEEHV by using a PRT to measure the temperature rise, which requires additional microfabrication and instrumentation, but in principle the temperature rise could instead be measured directly by SEM thermometry which is less accurate but simpler and noninvasive. 43 Note also that knowledge of G is not needed because it never enters into the calculation of the MEEHV (recall that the MEEHV was found in Figure 1b using arbitrary units on the E-axis). Knowledge of the MEEHV is also helpful for thermal metrologies which use the e-beam as a heater, because operating at the MEEHV gives the peak heating which maximizes the signal-to-noise ratio.…”

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confidence: 99%

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Adapting the Electron Beam from SEM as a Quantitative Heating Source for Nanoscale Thermal Metrology

Yuan

Ogletree

et al. 2020

Nano Lett.

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The electron beam (e-beam) in the scanning electron microscopy (SEM) provides an appealing mobile heating source for thermal metrology with spatial resolution of ∼1 nm but the lack of systematic quantification of the e-beam heating power limits such application development. Here, we systemically study ebeam heating in LPCVD silicon nitride (SiN x) thin-films with thickness ranging from 200 to 500 nm from both experiments and complementary Monte Carlo simulations using the CASINO software. There is good agreement about the thickness-dependent e-beam energy absorption of thin-film between modeling predictions and experiments. Using the absorption results we then demonstrate adapting e-beam as a quantitative heat source by measuring the thickness-dependent thermal conductivity of SiN x thin-films, with the results validated to within 7% by a separate Joule heating experiment. The results described here will open a new avenue to using SEM e-beams as a mobile heating source for advanced nanoscale thermal metrology development. The interaction between the high-kinetic energy electrons from an electron beam (e-beam) and a sample produces a wealth of signals which provide a variety of insights for scanning electron microscopy (SEM), such as analyzing composition, imaging surface morphology, and investigating the crystalline structures. During the electron−substrate interaction, heat is also generated and this makes it possible to apply the e-beam as a high-quality mobile heat source for generating nanoscale thermal hotspots but also for thermal studies in SEM and transmission electron microscopy (TEM). 1−6 E-beams have several unique characteristics which are appealing for nanoscale thermal metrology. First, an e-beam's potential spatial resolution of ∼1 nm is appealing compared to that of alternate techniques for nanoscale thermal measurements, such as the 3ω method, time/frequency-domain thermoreflectance, and Raman/luminescence-based methods, which are generally limited by the microfabrication length scale or optical diffraction limit. 7−9 Similarly, focusing a high-energy e-beam into such a small area results in nanoscale heat sources with extraordinarily high heat fluxes, easily exceeding ∼1 MW cm −2. This is valuable for the study of heat dissipation from nanoscale hotspots, which is important for both fundamental understanding and engineering design in micro-and nanoelectronics, because nanometer-scale hotspots of up to hundreds of degrees Celsius are believed to influence device performance and reliability. 10 Furthermore, compared to Joule heating by microfabricated heater lines or scanning with a 48 heated atomic force microscope tip, 11,12 the e-beam's 49 dynamically controllable shape and position makes it a more 50 nimble heat source for precise manufacturing and thermal 51 studies.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Adapting the Electron Beam from SEM as a Quantitative Heating Source for Nanoscale Thermal Metrology

Yuan

Ogletree

et al. 2020

Nano Lett.

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“…Figure 1 shows a comparison between the simulated and experimental temperature dependencies of the total electron (TE = SE + backscattering electron [BSE]) yield, aiming to prove the reliability of the MC model. As a statement, although there is currently no temperature‐dependent experimental data reported on the Au element, Figure 1 adopts recent temperature‐dependent TE yield data for the silicon element measured by Khan et al [ 8 ] . It can be observed that the simulated curve is among the experimental data, indicating that an acceptable comparison has been achieved.…”

Section: Resultsmentioning

confidence: 99%

Relation between Temperature and Line‐Scan Profile of a Spherical Nanoparticle under an Electron Beam Irradiation

Zhang

2023

Physica Status Solidi (b)

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The scanning electron microscope (SEM) is primarily used for imaging observation rather than as a tool for thermometry. This study explores the temperature‐dependent electron emission with a main focus on the line‐scan profile of two systems: one consisting of beryllium (Be) nanospheres (Be‐NS) and another consisting of gold (Au) NS (Au‐NS) on a Be substrate using Monte Carlo simulation. The relations between two types of electron signals with the temperature and the sample size at different primary electron (PE) energies are first recorded. This study concludes that the shape of the secondary‐electron line‐scan profile changes with the temperature for various sizes of a NS both in Au/Be and in Be/Be systems. However, the shape of the backscattering electron line‐scan profile remains almost unchanged with the temperature in the Au/Be system, but exhibits obvious changes in the Be/Be system. This work next investigates the spatial distributions of the deposited electron energy resulting from full electrons, the PEs, and the cascaded electrons at different temperatures. It indicates that the inherent temperature exerts different influences on scatterings of PEs and the cascaded electrons. Utilizing the electron–solid interaction theory, a systematic explanation is provided for these findings. This study potentially offers a possibility for thermometry in nanostructures using SEMs.

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“…Third, photoabsorption-induced heating or strain can also change the scattering processes in the sample and affect the net secondary electron yield. 37 For a monolayer of silicon nanoparticles, the absorbed laser power is less than 2.5% of the total incident power at 532 nm. The bulk aluminum-coated silicon substrate also provides good thermal conductance.…”

mentioning

confidence: 99%

“…The first two mechanisms (photon-impact-first electron-assisted and electron-impact-first photon-assisted) could be important in SUEM experiments but are unlikely to be relevant for the experimental conditions used here. Third, photoabsorption-induced heating or strain can also change the scattering processes in the sample and affect the net secondary electron yield . For a monolayer of silicon nanoparticles, the absorbed laser power is less than 2.5% of the total incident power at 532 nm.…”

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confidence: 99%

Photoabsorption Imaging at Nanometer Scales Using Secondary Electron Analysis

Zhang

Martis

et al. 2021

Nano Lett.

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Optical imaging with nanometer resolution offers fundamental insights into light–matter interactions. Traditional optical techniques are diffraction limited with a spatial resolution >100 nm. Optical super-resolution and cathodoluminescence techniques have higher spatial resolutions, but these approaches require the sample to fluoresce, which many materials lack. Here, we introduce photoabsorption microscopy using electron analysis, which involves spectrally specific photoabsorption that is locally probed using a scanning electron microscope, whereby a photoabsorption-induced surface photovoltage modulates the secondary electron emission. We demonstrate spectrally specific photoabsorption imaging with sub-20 nm spatial resolution using silicon, germanium, and gold nanoparticles. Theoretical analysis and Monte Carlo simulations are used to explain the basic trends of the photoabsorption-induced secondary electron signal. Based on our current experiments and this analysis, we expect that the spatial resolution can be further improved to a few nanometers, thereby offering a general approach for nanometer-scale optical spectroscopic imaging and material characterization.

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Temperature dependence of secondary electron emission: A new route to nanoscale temperature measurement using scanning electron microscopy

Cited by 12 publications

References 24 publications

Adapting the Electron Beam from SEM as a Quantitative Heating Source for Nanoscale Thermal Metrology

Adapting the Electron Beam from SEM as a Quantitative Heating Source for Nanoscale Thermal Metrology

Relation between Temperature and Line‐Scan Profile of a Spherical Nanoparticle under an Electron Beam Irradiation

Photoabsorption Imaging at Nanometer Scales Using Secondary Electron Analysis

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