Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Quantitative TEM characterizations of La/B4C and Mo/B4C ultrathin multilayer gratings by the geometric phase method

: Häussler, D.; Spiecker, E.; Jäger, W.; Störmer, M.; Bormann, R.; Michaelsen, C.; Wiesmann, J.; Zwicker, G.; Benbalagh, R.; Andre, J.-M.; Jonnard, P.


Spinella, C. ; European Materials Research Society -EMRS-:
Nanoscale imaging and metrology of devices and innovative materials : Proceedings of the European Materials Research Society 2006 - Symposium F, EMRS volume 195 ; Nice, France, 29 May - 2 June 2006
Amsterdam: Elsevier, 2007 (Microelectronic engineering 84.2007, Nr.3)
Symposium F "Nanoscale Imaging and Metrology of Devices and Innovative Materials" <2006, Nice>
Conference Paper, Journal Article
Fraunhofer ISIT ()

Artificially fabricated multilayers that exploit the effect of Bragg diffraction at long wavelengths are used as X-ray optical components. Periodic ultrathin bilayer stacks of, alternatingly, a metallic reflection layer and a non-metallic spacer layer prepared as ?m-scaled surface grating promise particularly high performance in applications as X-ray filters for high-resolution spectroscopy. Such gratings can be prepared by multilayer deposition onto Si(0 0 1) gratings or by coating flat Si(0 1 1) substrate surfaces with a multilayer, followed by subsequent etching of a grating structure. The structural quality of ultrathin multilayer gratings of both types has been characterized quantitatively combining TEM bright-field imaging of specimen cross-sections and applying a geometric phase method. The geometric phase method has been originally developed for the analysis of local displacement fields from HREM images and allows to obtain the relevant structure parameters. The application of this method to the characterization of Mo/B4C and La/B4C multilayer systems shows that the functionally decisive structure parameters, such as layer perfection, layer periodicity, and layer orientation, can be obtained with high precision from evaluation of TEM bright-field images. The essential role of such data analyses for a quantitative characterization of multilayer systems and for optimising the layer deposition techniques in the fabrication of X-ray optical layer systems will be demonstrated and discussed.