Recent developments in secondary electron imaging

Howie, A.

doi:10.1111/j.1365-2818.1995.tb03678.x

Cited by 74 publications

(39 citation statements)

References 35 publications

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“…Castell et al 5 and Perovic et al 6,7 suggested that this phenomenon is due to surface band-bending. Howie 8 and Sealy et al 9 proposed that local external electric fields called patch fields are important for doping contrast. Patch fields can exist outside a semiconductor specimen due to charge variations on the surface.…”

Section: Introductionmentioning

confidence: 98%

A quantitative model for doping contrast in the scanning electron microscope using calculated potential distributions and Monte Carlo simulations

Chee

Broom

Humphreys

et al. 2011

Journal of Applied Physics

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This paper describes the use of a Monte Carlo model incorporating a finite-element method computing the electrostatic fields inside and outside a semiconductor, plus a ray-tracing algorithm for determining the doping contrast observed in a scanning electron microscope (SEM). This combined numerical method also enables the effects on the doping contrast of surface band-bending to be distinguished from those of external patch fields outside the specimen, as well as any applied macroscopic external fields from the detection system in the SEM. Good agreement of our new theory with experiment is obtained. The contrast characteristics in energy-filtered secondary electron images are also explained. The results of this work lead to a more advanced understanding of the doping contrast mechanisms, thereby enabling quantitative dopant profiling using the SEM.

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Section: Introductionmentioning

confidence: 98%

A quantitative model for doping contrast in the scanning electron microscope using calculated potential distributions and Monte Carlo simulations

Chee

Broom

Humphreys

et al. 2011

Journal of Applied Physics

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show abstract

“…Over the last decade attention has been devoted to direct secondary electron (SE) imaging of dopants [2][3][4][5][6][7][8][9][10][11][12][13]. The contrast between the p-and n-type semiconductor (mostly silicon) was found to reach as much as 10%.…”

Section: Introductionmentioning

confidence: 99%

The injected-charge contrast mechanism in scanned imaging of doped semiconductors by very slow electrons

Frank

Müllerová

2005

Ultramicroscopy

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“…Even after liquid water has been removed from a specimen surface, many materials can retain several layers of physisorbed water. It has been postulated that the local organization of these water molecules could alter the escape depth of secondary electrons, giving rise to unusual contrast effects (Howie, 1995).…”

Section: Implications For Imagingmentioning

confidence: 99%

An improved model for gaseous amplification in the environmental SEM

Thiel

Bache

Fletcher

et al. 1997

Journal of Microscopy

103

150

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SummaryWe present a new model for the gas amplification effect used in many environmental scanning electron microscopes, wherein molecular complexity is shown to be the critical factor. Monte Carlo simulations, based on experimental electron scattering cross-sections, are used to deduce a predictive model for the amplification process that is superior to the Townsend gas capacitor model. These predictions are compared with experimentally obtained amplification curves. Significantly, it is shown that the ionization efficiency of the electrons changes dramatically over the gap distance, and a constant value cannot be assumed. Atomic and molecular excitations affect the amplification process in two ways: first, they serve to lower the average kinetic energy of the imaging electrons, thereby keeping a greater fraction near the ionization threshold energy. Second, molecular normal modes determine the effectiveness of positive gas ions in producing additional secondaries upon surface impact. Practical implications such as signal gain and fraction of useful signal as a function of operating conditions are discussed in the light of the new model. Finally, we speculate on potential new contrast mechanisms brought about by the presence of an imaging gas.

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Recent developments in secondary electron imaging

Cited by 74 publications

References 35 publications

A quantitative model for doping contrast in the scanning electron microscope using calculated potential distributions and Monte Carlo simulations

A quantitative model for doping contrast in the scanning electron microscope using calculated potential distributions and Monte Carlo simulations

The injected-charge contrast mechanism in scanned imaging of doped semiconductors by very slow electrons

An improved model for gaseous amplification in the environmental SEM

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