News Article
FEI ChemiSTEM technology enables atomic-level spectroscopy
The combination of high detection sensitivity and high spectral rates are enabling better EDX mapping of materials that are highly sensitive to electron beam damage, such as composition analysis in nanometre-scale InGaN quantum wells used in LEDs and other compound semiconductor devices.
FEI, a leading instrumentation company providing systems for research and industry, is extending its ChemiSTEM Technology to enable, what it says for the first time, atomic-level energy dispersive X-ray (EDX) spectroscopy across the periodic table.
The combination of increased current in an atomic-sized probe by Caesium-correction and the increase in X-ray detection sensitivity and beam current of the ChemiSTEM Technology allows results to be obtained within minutes.
The images show atomic-level EDX spectroscopy of the material Strontium Titanate; the individual atomic positions of the crystal structure can be easily distinguished by their chemical signal (red is Strontium, green is Titanium).
"The powerful combination of the groundbreaking ChemiSTEM Technology and an aberration corrector offers unique capabilities for material science," said Ferdinand Hofer of Graz University of Technology, Austria. "One of the most important applications for the new technology will be element-specific imaging at atomic resolution. We will apply the technology to study interfaces in semiconductors, solar cell materials, LEDs and ceramic materials with previously unknown detection sensitivity and accuracy.
George Scholes, FEI's vice president for product management, adds, "The ChemiSTEM Technology will enable breakthough results in many key application areas for our customers, such as catalysis, metallurgy, microelectronics, and green energy materials, to name a few. For example, in a recent experiment with ChemiSTEM Technology, our customer was able to clearly resolve the core-shell structure of 5nm catalyst nanoparticles in about three minutes and with three times greater pixel resolution than a previous experiment with conventional technology. And the conventional technology failed after three hours of data collection to clearly resolve the same structure."
ChemiSTEM Technology achieves a factor of 50 or more enhancement in speed of EDX elemental mapping on scanning/transmission electron microscopes (S/TEMs) compared to conventional technology employing standard EDX Silicon-drift detectors (SDDs) and standard Schottky-FEG electron sources.
It combines FEI's proprietary X-FEG high brightness electron source, providing up to five times more beam current at a given spatial resolution; the patent-pending Super-X detection system, providing up to ten times or more detection sensitivity in EDX; and fast scanning electronics, capable of achieving EDX spectral rates of up to 100,000 spectra per second. Additionally, the windowless detector design employed for each of ChemiSTEM Technology's four integrated SDD detectors has proven to optimize the detection of both light and heavy elements.
This combination of high detection sensitivity and high spectral rates of up to 100,000 spectra per second are enabling better EDX mapping of materials that are highly sensitive to electron beam damage, such as composition analysis in nanometre-scale InGaN quantum wells used in LED devices, and semiconductor devices with potentially mobile dopant materials, as well as many others devices used in emerging nanotechnologies.
