Dynamic simulation of secondary electron emission and charging up of an insulating material

Ohya, Kaoru; Inai, K.; Kuwada, Hideaki; Hayashi, Teruyuki; Saito, Misako

doi:10.1016/j.surfcoat.2008.06.008

Cited by 40 publications

(22 citation statements)

References 11 publications

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“…4(a)), experimental data from refs [9] and [10] are depicted as well. As demonstrated in [8], the previous simulation in [2] results in much higher yield of SEs (by two to five times) in comparison with the experimental data, like as other simulation model [11]. One reason for the discrepancy should be a polarization effect.…”

Section: Ion Transport and Se Emission Without Charging Of Materialsmentioning

confidence: 83%

“…Some of the created electrons are emitted as a SE, but all the charges remaining in the material can fix traps so that the material charges up. In analogy to the charging model due to the bombardment with an electron [8], we have divided a SiO 2 -vacuum system ( Fig. 2(b)) into 500×500×500 cubic cells, except for the case of He ion bombardment.…”

Section: Charging Model Due To Bombardment Of Materials With Ionsmentioning

confidence: 99%

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Modeling of charging effects in scanning ion microscopes

et al. 2010

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Unwilling deformations of secondary electron (SE) images due to charging of an insulating layer on materials is one of important issues for semiconductor industry applications of scanning ion microscopes (SIM). This paper presents a Monte Carlo model of SE emission from SiO 2 in which the charging induced by ion bombardment at the energy range of tens of keV is taken into account. A self-consistent calculation is carried out for the transport of a projectile ion, recoiled material atoms and SEs, the creation of space charges trapped in the material and the resultant electric field in/out the material. Drift motion of trapped charges is calculated as well, where the recombination with a charge of opposite sign is taken into account. Therefore, the evolution of the charging is simulated with successive arrivals of ions. Since the surface voltage is positive due to ejection of SEs and injection of positive ions, some of ejected SEs are drawn back to the surface and can rebound on it; these SEs are unable to produce a net emission. Dynamic changes in the SE yield and surface voltage are compared among He ions, Ga ions and low-energy (<1 keV) electrons, along with the space charge distributions and the in/out electric fields. The net SE yield is decreased during ion bombardment and finally it vanishes, which is different from the case of electron bombardment where the net SE yield (including BSEs) is kept to one due to a balance between coming and outgoing electrons. Even if there is not net emission of SEs, the surface voltage does not reach any steady-state condition but progressively increases due to successive injection of positive ions. The growth rate of the surface voltage depends on both the SE yield with no charging and the spatial distribution of the ions penetrating into the material.

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Section: Ion Transport and Se Emission Without Charging Of Materialsmentioning

confidence: 83%

Section: Charging Model Due To Bombardment Of Materials With Ionsmentioning

confidence: 99%

Modeling of charging effects in scanning ion microscopes

et al. 2010

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“…Solution to the Boltzmann equation 1provides the energy distribution of electrons in the material. Their ejection from the surface is possible if their energy is larger than the work function which is 0.9 eV for quartz [33,34]. For low energy ejection, surface effects may modify the distribution [35].…”

Section: Kinetic Modeling Of the Laser Induced Electron Dynamicsmentioning

confidence: 99%

Evidence of noncollisional femtosecond laser energy deposition in dielectric materials

et al. 2020

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Electron dynamics in the bulk of large band gap dielectric crystals induced by intense femtosecond laser pulses at 800 nm is studied. With laser intensities (a few 10 TW/cm 2) under the ablation threshold, electrons with unexpected energies in excess of 40-50 eV are observed by using the photoemission spectroscopy. A theoretical approach based on the Boltzmann kinetic equation including state-of-the-art modeling for various particles interactions is developed to interpret these experimental observations. A direct comparison shows that both electron heating in the bulk and a further laser field acceleration after ejection from the material contribute equivalently to the final electron energy gain. The laser energy deposition in the material is shown to be significantly driven by a noncollisional process, i.e., direct multiphoton transitions between subbands of the conduction band. This work also sheds light on the contribution of the standard electron excitation/relaxation collisional processes, providing a new baseline to study the electron dynamics in dielectric materials and associated applications as laser material micromachining. To support such applications, a simple expression to evaluate the energy deposition by noncollisional absorption is provided.

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“…We model that following the approach suggested by Kieft and Bosch. 23 For insulators like SiO 2 , electron trapping due to polaronic effects has been reported by several authors, 12,36,37 but none of them is based on a first principle physics model. In this study, the nominal SE emission is unrealistically high (7 at its maximum) without explicit implementation of trapping cross-sections (Fig.…”

Section: Improvements On Inelastic Scatteringmentioning

confidence: 99%

Model improvements to simulate charging in scanning electron microscope

Arat

Klimpel

Hagen

2019

J. Micro/Nanolith. MEMS MOEMS

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Background: Charging of insulators is a complex phenomenon to simulate since the accuracy of the simulations is very sensitive to the interaction of electrons with matter and electric fields. Aim: In this study, we report model improvements for a previously developed Monte-Carlo simulator to more accurately simulate samples that charge. Approach: The improvements include both modeling of low energy electron scattering by first-principle approaches and charging of insulators by the redistribution of the charge carriers in the material with an electron beam-induced conductivity and a dielectric breakdown model. Results: The first-principle scattering models provide a more realistic charge distribution cloud in the material and a better match between noncharging simulations and experimental results. The improvements on the charging models, which mainly focus on the redistribution of the charge carriers, lead to a smoother distribution of the charges and better experimental agreement of charging simulations. Conclusions: Combined with a more accurate tracing of low energy electrons in the electric field, we managed to reproduce the dynamically changing charging contrast due to an induced positive surface potential.

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Dynamic simulation of secondary electron emission and charging up of an insulating material

Cited by 40 publications

References 11 publications

Modeling of charging effects in scanning ion microscopes

Modeling of charging effects in scanning ion microscopes

Evidence of noncollisional femtosecond laser energy deposition in dielectric materials

Model improvements to simulate charging in scanning electron microscope

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