High Spatial Resolution Low Energy Electron Beam X-ray Microanalysis

Abstract

<jats:p>Conventionally, x-ray microanalysis on scanning electron microscopes (SEM) with energy dispersive spectrometers (EDS) has been performed with relatively high primary energies (&gt;10 kv). for most samples this results in reasonably good separation of the generated x-ray line series from different elements enabling unambiguous identification and therefore accurate qualitative analysis. Under these circumstances it is widely accepted that quantitative analysis of polished bulk samples is possible on a routine basis with relative errors around 1-5% and detection limits of the order of 0.1%.</jats:p><jats:p>However, in order to address the analysis requirements of new advanced materials with sub-micron features, there is growing interest in performing x-ray microanalysis at low beam energies(&lt;5kv). this is now a more realistic goal due to the routine availability of field emission sem's which can operate with much improved beam sizes at low beam energies with sufficient beam current to perform practical microanalysis, in conjunction with the improved low energy performance of current, commercially available EDS systems.</jats:p>

Comprehensive Comparison of Various Techniques for the Analysis of Elemental Distributions in Thin Films

“…Cu, In, Ga, and Se distribution profiles across the Cu(In,Ga)Se 2 layer were extracted from corresponding EDX maps (256 × 196 pixels) acquired by use of a Thermo Noran X-ray detector and the Thermo Fisher Scientific software Noran System Six in a LEO GEMINI 1530 SEM, which is equipped with a field-emission gun. It has been shown (Barkshire et al, 2000) that spatial resolutions of down to 100 nm and below may be obtained in SEM-EDX measurements by reducing the acceleration voltage down to few kV. One prerequisite is that the acceleration voltage still is sufficient to excite the signals of all elements of interest in a sample, where in the present case, it is the In-L line, which exhibits the highest energy of the L lines of all matrix elements, of about 3.4 keV.…”

“…acquired by use of a Thermo Noran X-ray detector and the Thermo Fisher Scientific software Noran System Six in a LEO GEMINI 1530 SEM, which is equipped with a field-emission gun. It has been showñ Barkshire et al, 2000! that spatial resolutions of down to 100 nm and below may be obtained in SEM-EDX measurements by reducing the acceleration voltage down to few kV.…”

Electron Probe Microanalysis: A Review of the Past, Present, and Future

“…An FEG electron source yields a finely focused (<100 nm) electron beam with relatively high current (up to100 nA) even at low beam energies (<5 keV). At such energies, the effective ionization range of incident electrons drops from the conventional micrometer scale down to the sub-micrometer scale and leads to significant improvement in the lateral resolution and surface sensitivity of the technique (Barkshire et al, 2000; Newbury, 2002; Merlet & Llovet, 2012).…”

Interfacial Energy-Dispersive Spectroscopy Profile X-Ray Resolution Measurements in Variable Pressure SEM

“…Unfortunately, few attempts have been made to propose an estimate of the X-ray lateral resolution (Willich & Bethke, 1996; Reed, 1997; Barkshire et al, 2000). All of these estimations are based on using the X-ray generation range calculated by the expression of Castaing.…”

“…where E 0 (keV) is the primary beam energy, E c (keV) the critical excitation energy, ρ (g/cm 3 ) the density, and A and Z the mean atomic weight and mean atomic number, respectively. Unfortunately, few attempts have been made to propose an estimate of the X-ray lateral resolution (Willich & Bethke, 1996;Reed, 1997;Barkshire et al, 2000). All of these estimations are based on using the X-ray generation range calculated by the expression of Castaing.…”