SECRETS OF NANO WORLD: REVEAL BY SUPER X RAY MICROSCOPE

Researchers have been working on such super-resolution microscopy concepts for electrons and x-rays for many years. A novel super-resolution X-ray microscope developed by a team of researchers from Paul Scherrer Institute (PSI) and EPFL (ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE). They combine the high penetration power of x-rays with high spatial resolution, thereby creating possibility to shed light on the detailed interior composition of semiconductor devices and cellular structures.

The new instrument uses a Megapixel Pilatus detector which has excited the synchrotron community for its ability to count millions of single x-ray photons over a large area. This key feature makes it possible to record detailed diffraction patterns while the sample is raster-scanned through the focal spot of the beam. In contrast, conventional x-ray (or electron) scanning microscopes measure only the total transmitted intensity.

These diffraction data are then treated with an algorithm. An image reconstruction algorithm was developed that deals with the several tens of thousands of diffraction images and combines them into one super-resolution x-ray micrograph explains PSI researcher Pierre Thibault, first author on the publication. Even in order to achieve images of the highest precision, the algorithm not only reconstructs the sample but also the exact shape of the light probe resulting from the x-ray beam.

Conventional electron scanning microscopes can provide high-resolution images, but usually only for the surface of the specimen, and the samples must be kept in vacuum. The Swiss team's new super-resolution microscope bypasses these requirements, meaning that scientists will now be able to look deeply into semiconductors or biological samples without altering them. It can be used to non-destructively characterize nanometer defects in buried semiconductor devices and to help improve the production and performance of future semiconductor devices with sub-hundred-nanometer features. A further very promising application of the technique is in high-resolution life science microscopy, where the penetration power of X-rays can be used to investigate embedded cells or sub-cellular structures. Finally, the approach can also be transferred to electron or visible laser light, and help in the design of new and better light and electron microscopes.