Towards sub-micrometer high aspect ratio X-ray gratings by atomic layer deposition of iridium

Vila‐Comamala, Joan; Romano, Lucia; Guzenko, Vitaliy A.; Kagias, Matias; Stampanoni, Marco; Jefimovs, Konstantins

doi:10.1016/j.mee.2018.01.027

Cited by 42 publications

(29 citation statements)

References 28 publications

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“…In the following section, we address the fabrication of Si templates that can be used directly as phase modulating gratings or be subsequently filled with high X-ray absorbing materials, such as Ir 70 or Au, 71 and used as analyser gratings. Patterned metal layers were produced by following the schematic procedure of Fig.…”

Section: Patterned Structures For X-ray Opticsmentioning

confidence: 99%

Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics

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Section: Patterned Structures For X-ray Opticsmentioning

confidence: 99%

Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics

et al. 2020

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“…The results reported here allow us to extend the application energy range of the absorption gratings. Gold electroplating remains the most popular method for filling the Si trenches, but other methods can also be potentially used for different absorbing materials [ 53 , 54 , 55 ].…”

Section: Discussionmentioning

confidence: 99%

Towards the Fabrication of High-Aspect-Ratio Silicon Gratings by Deep Reactive Ion Etching

et al. 2020

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The key optical components of X-ray grating interferometry are gratings, whose profile requirements play the most critical role in acquiring high quality images. The difficulty of etching grating lines with high aspect ratios when the pitch is in the range of a few micrometers has greatly limited imaging applications based on X-ray grating interferometry. A high etching rate with low aspect ratio dependence is crucial for higher X-ray energy applications and good profile control by deep reactive ion etching of grating patterns. To achieve this goal, a modified Coburn–Winters model was applied in order to study the influence of key etching parameters, such as chamber pressure and etching power. The recipe for deep reactive ion etching was carefully fine-tuned based on the experimental results. Silicon gratings with an area of 70 × 70 mm2, pitch size of 1.2 and 2 μm were fabricated using the optimized process with aspect ratio α of ~67 and 77, respectively.

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“…The setup is expected to have a field of view up to 2 cm and a high spatial resolution (<10 μm) while using an effective X-ray energy of 20 keV and an approximate geometric magnification of a factor of 2. Our most relevant advances are focused in 1) the use of a structured X-ray source developed by SIGRAY, Inc. [4], that removes the requirement of using a G 0 grating; 2) the use of high Talbot orders using small grating periods of 1 μm [5], to greatly increase the phase sensitivity of the interferometer; and 3) the investigation of different sample preparation techniques to optimize the quality and quantitativeness of the phase contrast tomographic reconstructions. Fig.…”

Section: Histopathological Examination Of Tissue Specimens Is a Centrmentioning

confidence: 99%

“…As reported in ref. [5], we have also developed a new microfabrication technique combining deep reactive ion etching of silicon with atomic layer deposition to fabricate gratings with a period of 1 μm and a groove depth of 30 μm. Such gratings can be used to build a system using a high Talbot order interferometer, which enables a much higher phase sensitivity while keeping the total length of the setup short.…”

Section: Histopathological Examination Of Tissue Specimens Is a Centrmentioning

confidence: 99%

Development of Laboratory Grating-based X-ray Phase Contrast Microtomography for Improved Pathology

et al. 2018

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Histopathological examination of tissue specimens is a central diagnostic technique in clinical medicine. The examination relies on the patient's tissue preparation including chemical fixation, very thin sectioning, staining, and subsequent optical microscopy inspection. In this work, we aim to investigate and promote the use of X-ray phase contrast microtomography [1, 2, 3] in histopathology. Taking advantage of the higher sensitivity of X-ray phase contrast is especially well-suited for biological soft tissues, for which standard X-ray absorption does not typically yield enough signal to noise contrast. Furthermore, the use of X-ray phase contrast could possibly reduce the requirement of chemical staining in some conditions, thus enabling an examination of a tissue that is closer to its natural state and X-ray microtomography does not damage the tissue as the sectioning is virtually performed a posteriori on the three-dimensional reconstructed image of the sample.We are developing a new laboratory X-ray grating interferometry system using an X-ray microsource, in-house fabricated X-ray gratings and a high resolution scintillator-based X-ray detector. The setup is expected to have a field of view up to 2 cm and a high spatial resolution (<10 μm) while using an effective X-ray energy of 20 keV and an approximate geometric magnification of a factor of 2. Our most relevant advances are focused in 1) the use of a structured X-ray source developed by SIGRAY, Inc. [4], that removes the requirement of using a G 0 grating; 2) the use of high Talbot orders using small grating periods of 1 μm [5], to greatly increase the phase sensitivity of the interferometer; and 3) the investigation of different sample preparation techniques to optimize the quality and quantitativeness of the phase contrast tomographic reconstructions. Fig. 1(a) shows the current laboratory G 0 -less X-ray phase contrast microtomography setup at the Paul Scherrer Institut using structured X-ray microsource (SIGRAY, Inc.) and fig. 1(b) shows a slice from a phase contrast tomographic reconstruction of the eye of mouse obtained with such a G 0 -less system and with an approximate spatial resolution of 20 μm. The data was acquired combining the structured X-ray anode with a set of gratings G 1 and G 2 with periods of 3 μm. As reported in ref.[5], we have also developed a new microfabrication technique combining deep reactive ion etching of silicon with atomic layer deposition to fabricate gratings with a period of 1 μm and a groove depth of 30 μm. Such gratings can be used to build a system using a high Talbot order interferometer, which enables a much higher phase sensitivity while keeping the total length of the setup short. Finally, fig. 2 and tab. 1 show the quantitative phase tomographic reconstruction of human breast cancer biopsy in formalin demonstrating that biological specimens can be imaged with minimal sample

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Towards sub-micrometer high aspect ratio X-ray gratings by atomic layer deposition of iridium

Cited by 42 publications

References 28 publications

Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics

Metal assisted chemical etching of silicon in the gas phase: a nanofabrication platform for X-ray optics

Towards the Fabrication of High-Aspect-Ratio Silicon Gratings by Deep Reactive Ion Etching

Development of Laboratory Grating-based X-ray Phase Contrast Microtomography for Improved Pathology

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