High-efficiency fresnel zone plates for hard X-rays by 100 keV e-beam lithography and electroplating

The fabrication and characterization of Fresnel zone plates (FZPs) for hard X-ray microscopy applications are reported. High-quality 500 nm- and 1 m-thick Au FZPs with outermost zone widths down to 50 nm and 70 nm, respectively, and with diameters up to 600 m were fabricated. The diffraction efficiencies of the fabricated FZPs were measured for a wide range of X-ray energies (2.8-13.2 keV) showing excellent values up to 65-75% of the theoretical values, reflecting the good quality of the FZPs. Spatially resolved diffraction efficiency measurements indicate the uniformity of the FZPs and a defect-free structure.