Analysis Using FE-EPMA
(Field Emission-Electron Probe Micro-Analyser)

Measurement/Analysis Method

Overview

FE-EPMA enables element analysis in a minute area of approx. 100 nm in size. Also, using EDX, it is possible to analyze element combinations that are difficult to analyze since the peaks of elements overlap each other (Fe and F, Cr and O, Si, Ta and W, Mo and S) by separating them.

Quantitative evaluation of film thickness distribution in thin film is possible as well.

• Features of FE-EPMA

  • Element qualitative analysis of minute area
    Spatial resolution: 150 nm (370 nm conventionally)
  • High-definition element mapping analysis
    Maximum magnification: 20,000x (5,000x conventionally)
  • High-sensitivity analysis
    Analysis sensitivity: several hundred ppm (0.5% in SEM-EDX)
    C quantitative analysis precision: 0.1% (unavailable in SEM-EDX)
  • Applicable to almost all combinations from B to U(separation is impossible with SEM-EDX)
    Analysis of combinations Cr and O, Fe and F, Mo and S, and Ag and Pd is possible.
  • Analysis software with abundant functions
    Phase distribution, particle size distribution, film thickness evaluation, determination of thin film, etc.
  • Capable of handling large-size sample
    Maximum size: 100 mm x 100 mm x 75 mm in height

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Example Cases of Analysis to which FE-EPMA can be Applied

Analysis Case 1: Distribution of Fine Precipitates Dispersed in Pb-Free Free-Cutting Steel

The following is a case example where the element mappings were conducted in the same location under the same conditions by FE-EPMA and a conventional equipment (W-type EPMA). In mapping by FE-EPMA, as electron beams can be sufficiently narrowed even with a high current of 100 nA during analysis, it is possible to clearly identify the shape and size of fine precipitates of 1 μm or less in size. JFE-TEC is capable of proposing data analysis, including histograms and particle size distribution, using particle measurement software and phase analysis software according to the customer's needs.

Mn and S plane distribution in Pb-free free-cutting steel - comparison between FE-EPMA and conventional EPMA - (accelerating voltage: 10 kV, current value: 100 nA)

Analysis Case 2: Concentration Distribution of Cr-Depleted Layer in Sensitized Stainless Steel

In ferrite-based stainless steel, the way Cr-depleted layer was produced near Cr carbide precipitated in the crystal grain boundary could be observed. The observation reveals the concentration difference by several percent in submicron areas.

Cr and Fe concentration plane distribution and grain boundary line distribution in surface of sensitized ferrite-based stainless steel
(accelerating voltage: 10 kV, current value: 100 nA)

Analysis Case 3: Section Observation Case of Light-Emitting Diode Mounted on Cellular Phone

The following is a case example of SEM observation and line analysis by FE-EPMA and LaB6-type EPMA in the same condition. In FE-EPMA, the interface is clearly visible and fine multilayer structure of several tens of nanometers in size can be confirmed. If the spatial resolution is evaluated on the basis of interface between GaP and AlPIn, it has been enhanced 2.5 times from the conventional equipment.

• Backscattered electron image (20,000X)

  

• Distance from interface (nm)

  

SEM photograph and Ga line distribution of section of light-emitting diode and interface resolution -
omparison between FE-EPMA and conventional EPMA - (accelerating voltage: 5 kV)

• 		FE-EPMA	Conventional EPMA
  Electron gun		ZrO/W chip	W, LabB6, CeB6
  Accelerating voltage		3 - 25kV	10 - 25kV
  Minimum beam diameter	During observation	8 nm	W 40 nm LaB6 25 nm
  	During analysis	0.1 μm	W 0.5 μm LaB6 0.3 μm
  Minimum plane analysis area		5 μm	30μm

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