HIGH-RESOLUTION ZONE-DOUBLED transmission X-ray microscopy, and focusing diffraction
FRESNEL ZONE PLATES FOR X-RAY RADIATION efficiencies of 7.5% at 6.2-keV photon energy [3]. These
developments represent a significant step towards 10 nm
Joan Vila-Comamala1 spatial resolution for hard X-ray energies. In addition to
X-Ray Science Division, Argonne National Laboratory, conventional characterization techniques, we have used
9700 South Cass Ave., Argonne, IL 60439 ptychographic scanning coherent diffractive imaging to
obtain a 3D reconstruction of the hard X-ray beam focus
INTRODUCTION of a high-resolution Fresnel zone plate with an outermost
zone width of 20 nm, with high spatial resolution and
X-ray microscopy based on Fresnel zone plates is a dynamic range.
powerful technique for sub-100-nm resolution imaging of
biological and inorganic materials. Here, we report on the ACKNOWLEDGMENTS
modeling, fabrication, and characterization of zone-
doubled Fresnel zone plates (FZPs) for the multi-keV The research leading to these results has received funding
regime (4―12 keV), as shown in the figure. from the European Community’s Seventh Framework
Programme (FP7/2007-2013) under grant agreement No.
EXPERIMENTAL 226716.
REFERENCES
The FZPs were fabricated by combining electron-beam
lithography and atomic layer deposition of iridium [1,2]. 1. K. Jefimovs, J. Vila-Comamala, T. Pilvi, J. Raabe, M.
The experiments to test the fabricated devices were Ritala, and C. David. Phys. Rev. Lett. 99, 264801 (2007).
carried out at the coherent small angle X-ray scattering
(cSAXS) beamline of the Swiss Light Source, Paul 2. J. Vila-Comamala, S. Gorelick, V. A. Guzenko, E.
Scherrer Institut. F¨arm, M. Ritala, and C. David. Nanotechnology 21,
285305 (2010).
RESULTS
3. J. Vila-Comamala, S. Gorelick, E. F¨arm, C. M.
We demonstrate unprecedented spatial resolution by Kewish, A. Diaz, R. Barrett, V. A. Guzenko, M. Ritala,
resolving 15-nm lines and spaces in scanning and C. David. Opt. Express 19, 175–184 (2011).
Figure.
Scanning electron micrographs of a
zone-doubled Fresnel zone plate
made of HSQ resist and iridium
(100 um diameter, outermost zone
width of w = dr = 20 nm and height
of h ~ 550 nm). (a) Overview image
of the diffractive X-ray lens. (b)
High magnification top image of the
outermost region of the HSQ resist
template before the iridium
deposition. The pattern is made of
20 nm-wide lines and 80 nm period.
(c) and (d) show tilted views of the
edge of the zone-doubled Fresnel
zone plate before and after the
iridium coating by atomic layer
deposition (tilt angle of 50). The
resulting structure contains an
effective iridium grating made of 20
nm lines and spaces with an aspect
ratio of h = w > 27.5.
1
Former address:
Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland