Quantitative EPMA of element depth distribution

In its conventional application the electron probe microanalysis (EPMA) is a suitable technique for the quantitative microanalysis of samples, which are homogeneous inside the excited volume. Depending on the beam energy and the target composition the measured x-ray intensities are emerging from depths between about 50 nm and some microns. They contain an integral information about the composition of the excited volume. Nevertheless, the sensitivity of this technique also allows the detection of thin films on substrates with thicknesses even less than one monolayer. For such samples composed inhomogeneously near the surface, e.g. thin layers on substrates or sandwich structures, detailed quantitative informations can only be obtained when the integral information can be deconvoluted properly from the intensities. A necessary prerequisite to solve this problem is the exact knowledge of the depth distribution of the generated x-ray intensities ϕ(ρz) in samples which are inhomogeneous inside the excited volume. Up to now ϕ(ρz) is rather unknown for such samples.

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Applications of SIMS to electronic materials and devices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133047 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1682-1683

Author(s):

S.F. Corcoran

Keyword(s):

Depth Distribution ◽

Secondary Ion Mass Spectrometry ◽

Semiconductor Device ◽

Electronic Materials ◽

Profile Analysis ◽

Semiconductor Industry ◽

Small Diameter ◽

Depth Resolution ◽

Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

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Fluorescence effects in quantitative microprobe analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134533 ◽

1990 ◽

Vol 48 (2) ◽

pp. 188-189

Author(s):

S.J.B. Reed

Keyword(s):

Microprobe Analysis ◽

Depth Distribution ◽

Exciting Radiation ◽

Primary Radiation ◽

List Type ◽

Type Number ◽

Computing Power ◽

X Ray ◽

Fluorescent Radiation

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.

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Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132741 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1622-1623

Author(s):

G.F. Bastin ◽

H.J.M. Heijligers

Keyword(s):

Background Subtraction ◽

Electron Probe ◽

Detection System ◽

Higher Order ◽

Light Elements ◽

Strong Suppression ◽

Electron Probe Microanalyzer ◽

Quantitative Epma ◽

Peak Count ◽

Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

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A New Numerical Model for Electron-Probe Analysis at High Depth Resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016491x ◽

1996 ◽

Vol 54 ◽

pp. 490-491

Author(s):

P.-F. Staub ◽

C. Bonnelle ◽

F. Vergand ◽

P. Jonnard

Keyword(s):

Electron Probe ◽

Surface Segregation ◽

Depth Distribution ◽

Computing Time ◽

Depth Resolution ◽

Physical Parameters ◽

Electron Probe Analysis ◽

Interface Phases ◽

Excitation Conditions ◽

High Depth

Characterizing dimensionally and chemically nanometric structures such as surface segregation or interface phases can be performed efficiently using electron probe (EP) techniques at very low excitation conditions, i.e. using small incident energies (0.5<E0<5 keV) and low incident overvoltages (1<U0<1.7). In such extreme conditions, classical analytical EP models are generally pushed to their validity limits in terms of accuracy and physical consistency, and Monte-Carlo simulations are not convenient solutions as routine tools, because of their cost in computing time. In this context, we have developed an intermediate procedure, called IntriX, in which the ionization depth distributions Φ(ρz) are numerically reconstructed by integration of basic macroscopic physical parameters describing the electron beam/matter interaction, all of them being available under pre-established analytical forms. IntriX’s procedure consists in dividing the ionization depth distribution into three separate contributions:

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Climate warming affects the depth distribution of marine ectotherms

Marine Ecology Progress Series ◽

10.3354/meps13595 ◽

2020 ◽

Author(s):

S Thatje

Keyword(s):

Climate Warming ◽

Depth Distribution

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A STUDY ON SNOW DEPTH DISTRIBUTION ON WINDWARD SLOPE AND LEEWARD SLOPE USING AIRBORNE LASER SCANNING

Journal of Japan Society of Civil Engineers Ser B1 (Hydraulic Engineering) ◽

10.2208/jscejhe.74.i_883 ◽

2018 ◽

Vol 74 (4) ◽

pp. I_883-I_888

Author(s):

Terumasa NISHIHARA ◽

Atsushi TANISE

Keyword(s):

Snow Depth ◽

Laser Scanning ◽

Depth Distribution ◽

Airborne Laser Scanning ◽

Airborne Laser ◽

Windward Slope

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Depth distribution of algal species on the deep insular fore reef at Lee Stocking Island, Bahamas

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/s0967-0637(01)00011-5 ◽

2001 ◽

Vol 48 (10) ◽

pp. 2185-2194 ◽

Cited By ~ 32

Author(s):

Nilda E. Aponte ◽

David L. Ballantine

Keyword(s):

Depth Distribution ◽

Algal Species ◽

Fore Reef

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Measurement And Simulation Of X-Ray Emission From Multilayered Structures In Electron Probe Microanalysis.

Microscopy and Microanalysis ◽

10.1017/s1431927600013714 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 78-79

Author(s):

C. Merlet ◽

X. Llovet ◽

F. Salvat

Keyword(s):

Electron Probe ◽

Numerical Models ◽

Carbon Layer ◽

Single Element ◽

Surface Ionization ◽

Copper Films ◽

Multilayered Structures ◽

X Ray ◽

Electron Probe Microanalyzer ◽

Quantitative Epma

Studies of x-ray emission from thin films on substrates using an electron probe microanalyzer (EPMA) provide useful information on the characteristics of x-ray generation by electron beams. In this study, EPMA measurements of multilayered samples were performed in order to test and improve analytical and numerical models used for quantitative EPMA. These models provide relatively accurate results for samples consisting of layers with similar average atomic numbers, because of their similar properties regarding electron transport and x-ray generation. On the contrary, these models find difficulties to describe the process when the various layers have very different atomic numbers. In a previous work, we studied the surface ionization of thin copper films of various thicknesses deposited on substrates with very different atomic numbers. In the present communication, the study is extended to the case of multilayered specimens.The studied specimens consisted of thin copper films deposited on a carbon layer which, in turn, was placed on a variety of single-element substrates, ranging from Be to Bi.

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