Computational analysis of the surface permittivity and charging of dielectrics with the SEM-mirror technique

Sudarshan, Tangali S.; Wang, J.

doi:10.1109/14.204863

Cited by 14 publications

(5 citation statements)

References 10 publications

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“…13 We can estimate the effect of the chamber as follows. We replace the actual chamber by a fictitious spherical chamber having a radius H. Close to the charge under investigation, the field lines will reflect the structure of the charge distribution.…”

Section: A Effect Of the Chambermentioning

confidence: 99%

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Analysis of the scanning electron microscope mirror method for studying space charge in insulators

Wintle

1999

Journal of Applied Physics

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Articles you may be interested inMeasurement of surface potential of insulating film on a conductive substrate in a scanning electron microscope specimen chamberWe give a detailed analysis of the scanning electron microscope mirror method for studying a cloud of charge stored near the surface of an insulator, paying particular attention to the approximations that are often made. We discuss the effect of the finite size of the experimental chamber, of the thickness of the sample, and of relativistic corrections, and we demonstrate that interpretation of the observations cannot be unique. By making a detailed computation of the electron orbits in the presence of extended sources, we then test the commonly made assumption that the method measures the radius of curvature of the equipotentials, and we show that this is only partially true. Finally, we show that the sensitivity could be improved by increasing the scattering angle.

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Section: A Effect Of the Chambermentioning

confidence: 99%

“…This can be taken into account by calculating the field above the sample surface, either by use of the charge simulation method, 13 or by using the geometric images. 9 These methods can be used for films mounted on a ground plane ͑the usual geometry͒ or for self-supporting films in space.…”

Section: Thin Samplesmentioning

confidence: 99%

Analysis of the scanning electron microscope mirror method for studying space charge in insulators

Wintle

1999

Journal of Applied Physics

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“…According to the electric field distribution in the insulation material, some methods to reduce the electric field distortion at the electrode triple junction can be carried out by changing the material characteristic. For example, the permittivity has a nonnegligible effect on the surface flashover performance in vacuum reported in some researches [9][10][11][12][13][14]. Regardless of whether in the organic material [10] or the inorganic material [11], the higher the relative permittivity of the insulation material is, the worse the insulation performance in vacuum is generally.…”

Section: Functionally Graded Insulator Systemmentioning

confidence: 99%

Improvement of surface flashover in vacuum

2020

High Voltage

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Surface flashover of insulation systems is a basic issue in the field of high voltage and electrical insulation. To improve the surface flashover performance is of great significance for the development of advanced power transmission equipment and insulation materials. This study reviews the research progress of surface flashover in vacuum regarding to effective methods to improve the surface flashover performance in vacuum, including insulation system optimisation and material modification. The former one is beneficial to reduce the electric field distortion, and the later one is able to adjust the surface trap parameters of the material through physical and chemical methods. In addition, the 'U-shaped' curve is proposed to reveal the relationship between surface flashover voltage and surface trap level, discovering the synthetic effects of surface traps on surface flashover. It is expected that the 'U-shaped' curve will become a guidance to improve surface flashover performance through adjusting trap parameters. Moreover, several suggestions are made to build unified surface flashover model which is suitable to the range from high vacuum to high pressure.

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“…All these treatments can result in various degrees of near-surface deformation which is known to be accompanied by the generation of different densities and distributions of point defects [3]. To study the relation between structural modifications of the material surface and the electron dosedependent surface potential, charge-up of dielectrics has also intentionally been generated (SEM mirror effect [4]).…”

Section: Introductionmentioning

confidence: 99%

Scanning electron microscopical inspection of uncoated CaF2 single crystals

Johansen

Gogoll

Stenzel

et al. 1995

Phys. Stat. Sol. (a)

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Cleaved and mechanically polished surfaces of CaF2 single crystals in the uncoated state are investigated by means of secondary (SE) and backscattered (BE) electron imaging in the scanning electron microscope with respect to their strongly different charge‐up properties. There is a relationship between the density of preparation‐induced defects and the amount of surface charge detectable by characteristic image disturbances. Different electrical contacting techniques of the crystals are tested to obtain imaging free of charge. For the cleavage face the relatively low electrical resistance of the bulk material of ϱ ≈ 1013 Ω cm controls the imaging conditions rather than the electron trapping by cleavage‐induced surface defects. On mechanically polished surfaces already during the first slow scan with Ep > 5 keV an equipotential surface is formed leading to a pronounced electron mirror effect detectable by SE and BE. However, also in this case imaging of selected crystal areas free of disturbances succeeds if they are located within an electrical deceleration field.

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Computational analysis of the surface permittivity and charging of dielectrics with the SEM-mirror technique

Cited by 14 publications

References 10 publications

Analysis of the scanning electron microscope mirror method for studying space charge in insulators

Analysis of the scanning electron microscope mirror method for studying space charge in insulators

Improvement of surface flashover in vacuum

Scanning electron microscopical inspection of uncoated CaF2 single crystals

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