Nanofabrication of tungsten zone plates with integrated platinum central stop for hard X-ray applications

We present a nanofabrication process for producing tungsten zone plates used in hard X-ray applications including a method of integrating a high-energy absorbing central stop with the optic. Tungsten zone plates are structured with electron-beam lithography and subsequent reactive ion etching. The central stop originates from a platinum wire. It is cut to dimension by focused ion beam etching, and afterwards attached to the zone plate center using ion beam induced deposition of platinum. A zone plate with integrated central stop will simplify alignment in hard X-ray scanning microscope arrangements where the 0th order light must be eliminated. The focusing performance of the zone plate device was investigated by scanning coherent diffraction imaging (ptychography) at 8keV photon energy. We could demonstrate a diffraction-limited focus size of 53nm diameter full-width-at-half-maximum. Tungsten zone plates with integrated central stops show promising results for use in hard X-ray microscopes at high-brightness facilities.

[1]  Manuel Guizar-Sicairos,et al.  Characterization of high-resolution diffractive X-ray optics by ptychographic coherent diffractive imaging. , 2011, Optics express.

[2]  Weilun Chao,et al.  Demonstration of 12 nm resolution Fresnel zone plate lens based soft x-ray microscopy. , 2009, Optics express.

[3]  Anatoly Snigirev,et al.  Synchrotron hard x-ray microprobe: Fluorescence imaging of single cells , 2001 .

[4]  H. Hertz,et al.  Twelve nanometer half-pitch W–Cr–HSQ trilayer process for soft x-ray tungsten zone plates , 2011 .

[5]  Christian Bressler,et al.  Molecular structural dynamics probed by ultrafast X-ray absorption spectroscopy. , 2010, Annual review of physical chemistry.

[6]  Jörg Raabe,et al.  Advanced thin film technology for ultrahigh resolution X-ray microscopy. , 2009, Ultramicroscopy.

[7]  Elina Färm,et al.  Ultra-high resolution zone-doubled diffractive X-ray optics for the multi-keV regime. , 2011, Optics express.

[8]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[9]  Georg Weidenspointner,et al.  Femtosecond X-ray protein nanocrystallography , 2011, Nature.

[10]  P. Charalambous.  Fabrication and characterization of Tungsten zone plates for multi KeV X-rays , 2000 .

[11]  Christian G. Schroer,et al.  Hard X-ray nanoprobe at beamline P06 at PETRA III , 2010 .

[12]  Andrew G. Glen,et al.  APPL , 2001 .

[13]  O. Bunk,et al.  High-Resolution Scanning X-ray Diffraction Microscopy , 2008, Science.

[14]  J. Rodenburg,et al.  An improved ptychographical phase retrieval algorithm for diffractive imaging. , 2009, Ultramicroscopy.

[15]  Tim Salditt,et al.  Hard x-ray nanobeam characterization by coherent diffraction microscopy , 2010 .

[17]  Michael Feser,et al.  Nanofabrication of high aspect ratio 24nm x-ray zone plates for x-ray imaging applications , 2007 .