The single-scattering model and spatial resolution in X-ray analysis of thin foils

Reed, S. J. B.

doi:10.1016/0304-3991(82)90263-7

Cited by 95 publications

(47 citation statements)

References 13 publications

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“…In systems with a field emission gun~FEG!, there is enough current in a 2-nm beam to allow successful analysis of exceedingly thin specimens with 2-5-nm spatial resolution~Lyman, 1986; Williams et al, 2002!. However, for all AEMs, beam broadening in thicker specimens~Gold-stein et al, 1977Reed, 1982! will degrade the X-ray spatial resolution up to several times the beam size.…”

Section: Electron-beam Instrumentsmentioning

confidence: 99%

Tutorial Review: X-ray Mapping in Electron-Beam Instruments

Friel

Lyman

2006

Microsc. Microanal.

125

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This review traces the development of X-ray mapping from its beginning 50 years ago through current analysis procedures that can reveal otherwise obscure elemental distributions and associations. X-ray mapping or compositional imaging of elemental distributions is one of the major capabilities of electron beam microanalysis because it frees the operator from the necessity of making decisions about which image features contain elements of interest. Elements in unexpected locations, or in unexpected association with other elements, may be found easily without operator bias as to where to locate the electron probe for data collection. X-ray mapping in the SEM or EPMA may be applied to bulk specimens at a spatial resolution of about 1 mm. X-ray mapping of thin specimens in the TEM or STEM may be accomplished at a spatial resolution ranging from 2 to 100 nm, depending on specimen thickness and the microscope. Although mapping has traditionally been considered a qualitative technique, recent developments demonstrate the quantitative capabilities of X-ray mapping techniques. Moreover, the long-desired ability to collect and store an entire spectrum at every pixel is now a reality, and methods for mining these data are rapidly being developed.

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Section: Electron-beam Instrumentsmentioning

confidence: 99%

Tutorial Review: X-ray Mapping in Electron-Beam Instruments

Friel

Lyman

2006

Microsc. Microanal.

125

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“…One of the most popular approaches to define the spatial resolution is to use the diameter at the midpoint of the truncated cone defined by the incident and exit beam diameters (Michael et al, 1990;Williams et al, 1992). This approach employs a single-scattering model (Goldstein et al, 1977;Reed, 1982) to describe the beam broadening and gives good agreement between experimental and simulated results (Williams et al, 1992), in spite of neglecting the electron intensity distribution in the incident beam or in the interaction volume. Recently, Keast & Williams (2000) evaluated various beam-broadening models by fitting to segregation profiles across grain boundaries and concluded that the Gaussian beam-broadening model (Doig et al, 1980;Doig & Flewitt, 1982) is the best description of the interaction volume.…”

Section: Determination Of Spatial Resolutionmentioning

confidence: 99%

The quantitative analysis of thin specimens: a review of progress from the Cliff‐Lorimer to the new ζ‐factor methods

Watanabe

Williams

2006

Journal of Microscopy

235

210

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SummaryA new quantitative thin-film X-ray analysis procedure termed the ζ -factor method is proposed. This new ζ -factor method overcomes the two major limitations of the conventional CliffLorimer method for quantification: (1) use of pure-element rather than multielement, thin-specimen standards and (2) built-in X-ray absorption correction with simultaneous thickness determination. Combined with a universal, standard, thin specimen, a series of ζ -factors covering a significant fraction of the periodic table can be estimated. This ζ -factor estimation can also provide information about both the detector efficiency and the microscope-detector interface system. Light-element analysis can also be performed more easily because of the built-in absorption correction. Additionally, the new ζ -factor method has several advantages over the Cliff-Lorimer ratio method because information on the specimen thickness at the individual analysis points is produced simultaneously with compositions, thus permitting concurrent determination of the spatial resolution and the analytical sensitivity. In this work, details of the ζ -factor method and how it improves on the Cliff-Lorimer approach are demonstrated, along with several applications.

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“…13 ͑Note that the islands studied here are dislocated.͒ From point A upwards, the Si/Ge ratio remains approximately constant. ͑This variation is not due to the beam broadening, as, using equations given by Reed 14 and the atomic parameters of Ge and Si, 15 a 100 keV electron beam with a 1 nm electron probe size gives a spatial resolution for EDX of better than 2 nm for foils of thickness less than 20 nm.͒ This constant ratio is not seen in the results of Chaparro et al 13 Detailed EDX analysis shows that, throughout the whole island, there is a tendency for the Si/Ge ratio to be higher closer to the substrate. This can be accounted for by the larger atoms ͑Ge͒ tending to be in the tensile regions and the smaller atoms ͑Si͒ to be in the compressive regions, to minimize the strain energy.…”

confidence: 99%

Composition and its impact on shape evolution in dislocated Ge(Si)/Si islands

Liao

Zou

Cockayne

et al. 2000

Applied Physics Letters

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The composition distribution of Ge(Si)/Si (001) islands grown at 700 °C by molecular beam epitaxy is investigated using high-spatial resolution x-ray energy dispersive spectrometry in a scanning transmission electron microscope. Island shapes are investigated using cross-section transmission electron microscopy. Results show nonuniformity of the composition distribution in the islands, which affects the evolution of the aspect ratios of height-to-base diameter of dislocated islands.

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The single-scattering model and spatial resolution in X-ray analysis of thin foils

Cited by 95 publications

References 13 publications

Tutorial Review: X-ray Mapping in Electron-Beam Instruments

Tutorial Review: X-ray Mapping in Electron-Beam Instruments

The quantitative analysis of thin specimens: a review of progress from the Cliff‐Lorimer to the new ζ‐factor methods

Composition and its impact on shape evolution in dislocated Ge(Si)/Si islands

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