Number of found documents: 578
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Nanopatterning of Silicon Nitride Membranes
Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
2017 - English
Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The principle of silicon nitride membranes preparation is based on the wet anisotropic etching of the bottom side of the silicon wafer with crystallographic orientation (100). While the basic procedure for the preparation of such membranes is well known, the nano patterning of thin membranes presents quite important challenges. This is partially due to the mechanical stress which is typically presented within such membranes. The resolution requirements of the\nmembrane patterning have gradually increased. Advanced lithographic techniques and etching procedures had to be developed. This paper summarizes theoretical aspects, technological issues and achieved results. The application potential of silicon nitride membranes as a base for multifunctional micro system (MMS) is also\ndiscussed. Keywords: e-beam writer; silicon nitride membranes; nano patterning; anisotropic etching Available at various institutes of the ASCR
Nanopatterning of Silicon Nitride Membranes

Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The ...

Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
Ústav přístrojové techniky, 2017

Parameter Optimization of Multi-Level Diffraction Gratings
Matějka, Milan; Kolařík, Vladimír; Horáček, Miroslav; Král, Stanislav
2017 - English
Originally, the e-beam lithography (EBL) is a technique for creating high-resolution black and white masks for the optical lithography. Multi-level relief structures can be also prepared using EBL patterning. Their preparation is based on the image patterning with a gradient of exposure doses. Large-area multi-level structures can be effectively prepared using the electron beam pattern generator with a variable shaped beam. We present several writing strategies. Basically, the main writing strategy uses one stamp (i.e. one elementary exposure of the shaped electron beam) per one elementary area with the same exposure dose. This simple approach is fast and flexible, however it does not guarantee optimal results. The main problem is an imperfection of the stamps (size, shape, and homogeneity). Advanced algorithms are based on multiple\nexposure of the same elementary area, the total local exposure dose is a sum of several different elementary exposures (stamps). Using these algorithms, a smoother surface of the structure can be achieved. On the other hand, the writing speed is considerably decreased. Tradeoff between the achieved parameters and the writing speed is discussed for selected set of writing strategy algorithms. Keywords: e-beam pattern generator; variable shaped beam; grayscale lithography; multi-level grating Available at various institutes of the ASCR
Parameter Optimization of Multi-Level Diffraction Gratings

Originally, the e-beam lithography (EBL) is a technique for creating high-resolution black and white masks for the optical lithography. Multi-level relief structures can be also prepared using EBL ...

Matějka, Milan; Kolařík, Vladimír; Horáček, Miroslav; Král, Stanislav
Ústav přístrojové techniky, 2017

Nežádoucí metabolické účinky aripiprazolu v poly I:C modelu schizofrenie u potkana
Horská, K.; Rudá-Kučerová, J.; Dražanová, Eva; Pistovčáková, J.; Karpíšek, M.; Kotolová, H.; Demlová, R.; Kašpárek, T.
2017 - English
The aim of this study was to evaluate metabolic phenotype of poly I:C rat model and asses metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of energy homeostasis. Altered lipid profile in poly I:C model was observed. Leptin and GLP-1 serum levels were significantly reduced, while ghrelin level was elevated. Our data indicate that dysregulation of adipose tissue endocrine function and gastrointestinal hormones is implicated in metabolic adverse effects of antipsychotics. Keywords: metabolic syndrome; aripiprazole; rat; poly I:C animal model Available at various institutes of the ASCR
Nežádoucí metabolické účinky aripiprazolu v poly I:C modelu schizofrenie u potkana

The aim of this study was to evaluate metabolic phenotype of poly I:C rat model and asses metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of ...

Horská, K.; Rudá-Kučerová, J.; Dražanová, Eva; Pistovčáková, J.; Karpíšek, M.; Kotolová, H.; Demlová, R.; Kašpárek, T.
Ústav přístrojové techniky, 2017

Phyllotactic Model Linking Nano and Macro World
Horáček, Miroslav; Meluzín, Petr; Krátký, Stanislav; Urbánek, Michal; Bok, Jan; Kolařík, Vladimír
2017 - English
Recently, the arrangement of diffraction primitives according to a phyllotactic model was presented. This arrangement was used to benchmarking purposes of the e-beam writer nano patterning. The phyllotactic arrangement has several interesting properties. One of them is related with the coherence between the nanoor microscopic domain of individual optical primitives and the properties of visually perceived images crated by these structures in the macro domain. This paper presents theoretical analysis of the phyllotactic arrangement in the referred context. Different approaches enabling the creation of diffractive optically variable images are proposed. The practical part of the presented work deals with the nano patterning of such structures using two different types of the e-beam pattern generators. One of them is a system with a variable shaped beam of electrons, while the other one is a system with a Gaussian-shaped beam. E-beam writing strategies and the use of inherent spiral patterns for exposure ordering and partitioning are also discussed. Keywords: nano patterning; spiral grating structure; phyllotactic pattern; e-beam writer Available at various institutes of the ASCR
Phyllotactic Model Linking Nano and Macro World

Recently, the arrangement of diffraction primitives according to a phyllotactic model was presented. This arrangement was used to benchmarking purposes of the e-beam writer nano patterning. The ...

Horáček, Miroslav; Meluzín, Petr; Krátký, Stanislav; Urbánek, Michal; Bok, Jan; Kolařík, Vladimír
Ústav přístrojové techniky, 2017

Structural Colors of Self-Similar Nano Patterns
Meluzín, Petr; Horáček, Miroslav; Krátký, Stanislav; Kolařík, Vladimír
2017 - English
E-beam lithography is a flexible technology for various diffraction gratings origination. The e-beam patterning typically allows for the creation of optical diffraction gratings in the first diffraction order. However, the very high resolution enables also the patterning of structures providing the zero-order diffraction. Recently, we presented a work on the structural colors of metallic layers covering both regular-line structures and CGH (computer generated hologram) structures. This work presents a study dealing with zero-order diffraction structures with self-similar properties. The practical part of the work is focused on two aspects: design parameters and technological issues. Variations in design parameters include the tone of the structure (positive or negative),\nthe density of filling, the filling factor, and the depth of the structures. The achieved gamut of colors may by primarily extended by the proper selection of metal deposition technology and its parameters, and further by the proper selection of the metal and the thickness of its layer; these are the technological issues. Keywords: e-beam writer; nano patterning; self similarity; diffraction grating Available at various institutes of the ASCR
Structural Colors of Self-Similar Nano Patterns

E-beam lithography is a flexible technology for various diffraction gratings origination. The e-beam patterning typically allows for the creation of optical diffraction gratings in the first ...

Meluzín, Petr; Horáček, Miroslav; Krátký, Stanislav; Kolařík, Vladimír
Ústav přístrojové techniky, 2017

Blaze Gratings with a Ribbed Back Slope
Krátký, Stanislav; Meluzín, Petr; Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Chlumská, Jana; Král, Stanislav
2017 - English
Binary relief phase-modulated gratings provide symmetrical diffraction of the incoming light beam. Asymmetrical gratings, e.g. asymmetrical triangular blazed gratings, are characteristic by an asymmetrical diffraction behavior, where one of the first diffraction orders is more important than the other one. Electron beam lithography is a suitable and flexible tool for patterning of such kind of gratings. High quality results can be readily obtained when the period of the grating is relatively large and the relief depth is relatively low, this is the case of gratings with a small blaze angle. As the blaze angle increases, the quality of result suffers from several patterning-related issues. One of the problems is a reflection of the incoming light beam from the back slope (anti-blaze facet) of the blaze grating. We propose a novel configuration, with a ribbed modulation of the back slope. This modulation is perpendicular to the direction of the grating grooves. This paper presents an analysis of the proposed blazed grating configuration. E-beam pattern generators were used to prepare a few\nsamples of blaze gratings with a ribbed back slope. One part of the experiment was performed with a Gaussianshaped beam and another one with the variable-shaped beam. Results of the experiment are presented.\nFinally, we discuss the optical performance of two blaze gratings with similar parameters, one of them is with the flat back slope and another one is with the ribbed back slope. Keywords: nano patterning; blazed diffraction grating; Gaussian-type beam; variable-shaped beam; electron beam writer Available at various institutes of the ASCR
Blaze Gratings with a Ribbed Back Slope

Binary relief phase-modulated gratings provide symmetrical diffraction of the incoming light beam. Asymmetrical gratings, e.g. asymmetrical triangular blazed gratings, are characteristic by an ...

Krátký, Stanislav; Meluzín, Petr; Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Chlumská, Jana; Král, Stanislav
Ústav přístrojové techniky, 2017

Scanning transmission microscopy at very low energies
Müllerová, Ilona; Mikmeková, Eliška; Konvalina, Ivo; Frank, Luděk
2016 - English
To operate down to units of eV with a small primary spot size, a cathode lens with a biased specimen was introduced into the SEM. The reflected signal, accelerated secondary and backscattered electrons, is collected by detectors situated above the specimen.\nWhen we insert a detector below the specimen, the transmitted electron signal can also be used for imaging down to zero energy. Fig. 1 also shows an example of the simulated signal trajectories of electrons that impact on the detector of reflected electrons, based on an Yttrium Aluminium Garnet (YAG) crystal, and trajectories of electrons transmitted through the specimen and incident on a semiconductor detector based on the PIN structure. Keywords: electron microscopy; SEM Available at various institutes of the ASCR
Scanning transmission microscopy at very low energies

To operate down to units of eV with a small primary spot size, a cathode lens with a biased specimen was introduced into the SEM. The reflected signal, accelerated secondary and backscattered ...

Müllerová, Ilona; Mikmeková, Eliška; Konvalina, Ivo; Frank, Luděk
Ústav přístrojové techniky, 2016

Optimal X-ray detection for thin samples in low-energy STEM
Rozbořil, Jakub; Oral, Martin; Radlička, Tomáš
2016 - English
In many applications it is desirable to perform energy-dispersive X-ray spectroscopy (EDS) on very thin samples at low primary beam energies in a STEM. Thin samples, or lamellae, with the thickness of about 10 nm, are mostly prepared in focused ion beam instruments (FIBs), and they are used to evaluate experiments in the development of thin films and coatings, in the semiconductor industry, and in other applications. EDS then provides a map of different chemical elements or compounds in the sample, obtained by scanning the electron beam in a raster. Often the qualitative composition is known as a limited set of materials and only their distribution on the sample is to be determined. For large batches of samples fast measurements are desired to maximize utilization of expensive equipment. In this study we found a method to minimize the time needed to reliably acquire an elemental map by determining the optimal detector placement and the minimal necessary primary electron dose per pixel. Keywords: electron microscopy; EDS; STEM Available at various institutes of the ASCR
Optimal X-ray detection for thin samples in low-energy STEM

In many applications it is desirable to perform energy-dispersive X-ray spectroscopy (EDS) on very thin samples at low primary beam energies in a STEM. Thin samples, or lamellae, with the thickness of ...

Rozbořil, Jakub; Oral, Martin; Radlička, Tomáš
Ústav přístrojové techniky, 2016

Large-area gray-scale structures in e-beam writer versus area current homogeneity and deflection uniformity
Kolařík, Vladimír; Horáček, Miroslav; Matějka, Milan; Krátký, Stanislav; Bok, Jan
2016 - English
The high stability and good current homogeneity in the spot of the e-beam writer is crucial to the exposure quality, particularly in the case of large-area structures when gray-scale lithography is used. Even though the deflection field distortion is calibrated regularly and beam focus and beam astigmatism is dynamically corrected over the entire deflection field,\nwe can observe disturbances in the exposed relief for both nowadays types of e-beam writers, the shaped e-beam writing system and the Gaussian e-beam writing system. A stable and homogeneous angular current density distribution in the spot is important especially in the case of shaped e-beam lithography systems. A non-homogeneity of the spot over deflection field is seen alongside the field boundaries of both lithography systems. Keywords: e-beam writer; Gaussian e-beam writing system Available at various institutes of the ASCR
Large-area gray-scale structures in e-beam writer versus area current homogeneity and deflection uniformity

The high stability and good current homogeneity in the spot of the e-beam writer is crucial to the exposure quality, particularly in the case of large-area structures when gray-scale lithography is ...

Kolařík, Vladimír; Horáček, Miroslav; Matějka, Milan; Krátký, Stanislav; Bok, Jan
Ústav přístrojové techniky, 2016

Principal component analysis of Raman spectroscopy data for determination of biofilm forming bacteria and yeasts
Šiler, Martin; Samek, Ota; Bernatová, Silvie; Mlynariková, K.; Ježek, Jan; Šerý, Mojmír; Krzyžánek, Vladislav; Hrubanová, Kamila; Holá, M.; Růžička, F.; Zemánek, Pavel
2016 - English
Many microorganisms (e.g., bacteria, yeast, and algae) are known to form a multi-layered structure composed of cells and extracellular matrix on various types of surfaces. Such a formation is known as the biofilm. Special attention is now paid to bacterial biofilms that are formed on the surface of medical implants, surgical fixations, and artificial tissue/vascular\nreplacements. Cells contained within such a biofilm are well protected against antibiotics and phagocytosis and, thus, effectively resist antimicrobial attack.\nA method for in vitro identification of individual bacterial cells as well as yeast colonies is presented. Figure 1 shows an an example of the biofilm formed by Staphylococcus epidermidis bacteria and Candida parapsilosis yeasts known for forming biofilms. The\npresented method is based on analysis of spectral “Raman fingerprints” obtained from the single cell or whole colony, see figure 2(top). Here, Raman spectra might be taken from the biofilm-forming cells without the influence of an extracellular matrix or directly form the bacterial/yeast colony. Keywords: electron microscopy; biofilm; Raman spectra Available at various institutes of the ASCR
Principal component analysis of Raman spectroscopy data for determination of biofilm forming bacteria and yeasts

Many microorganisms (e.g., bacteria, yeast, and algae) are known to form a multi-layered structure composed of cells and extracellular matrix on various types of surfaces. Such a formation is known as ...

Šiler, Martin; Samek, Ota; Bernatová, Silvie; Mlynariková, K.; Ježek, Jan; Šerý, Mojmír; Krzyžánek, Vladislav; Hrubanová, Kamila; Holá, M.; Růžička, F.; Zemánek, Pavel
Ústav přístrojové techniky, 2016

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