scholarly journals Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures

RSC Advances ◽  
2018 ◽  
Vol 8 (23) ◽  
pp. 12628-12634 ◽  
Author(s):  
Rabia Akan ◽  
Karolis Parfeniukas ◽  
Carmen Vogt ◽  
Muhammet S. Toprak ◽  
Ulrich Vogt
Keyword(s):  
Reaction Kinetics ◽  
Chemical Etching ◽  
Zone Plate ◽  
X Ray ◽  
Zone Plates ◽  
Aspect Ratios ◽  
Metal Assisted Chemical Etching ◽  
Silicon Based

Specially designed X-ray zone plates with high aspect-ratios have been fabricated via metal-assisted chemical etching, by controlling the reaction kinetics.

scholarly journals Metal-Assisted Chemical Etching and Electroless Deposition for Fabrication of Hard X-ray Pd/Si Zone Plates

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 301 ◽  
Author(s):  
Rabia Akan ◽  
Thomas Frisk ◽  
Fabian Lundberg ◽  
Hanna Ohlin ◽  
Ulf Johansson ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Chemical Etching ◽  
Electroless Deposition ◽  
Low Cost ◽  
Zone Plate ◽  
X Ray ◽  
Zone Plates ◽  
Aspect Ratios ◽  
Plate Design ◽  
Metal Assisted Chemical Etching

Zone plates are diffractive optics commonly used in X-ray microscopes. Here, we present a wet-chemical approach for fabricating high aspect ratio Pd/Si zone plate optics aimed at the hard X-ray regime. A Si zone plate mold is fabricated via metal-assisted chemical etching (MACE) and further metalized with Pd via electroless deposition (ELD). MACE results in vertical Si zones with high aspect ratios. The observed MACE rate with our zone plate design is 700 nm/min. The ELD metallization yields a Pd density of 10.7 g/cm 3 , a value slightly lower than the theoretical density of 12 g/cm 3 . Fabricated zone plates have a grid design, 1:1 line-to-space-ratio, 30 nm outermost zone width, and an aspect ratio of 30:1. At 9 keV X-ray energy, the zone plate device shows a first order diffraction efficiency of 1.9%, measured at the MAX IV NanoMAX beamline. With this work, the possibility is opened to fabricate X-ray zone plates with low-cost etching and metallization methods.

scholarly journals Investigation of Metal-Assisted Chemical Etching for Fabrication of Silicon-Based X-Ray Zone Plates

2018 ◽  
Vol 24 (S2) ◽  
pp. 290-291 ◽  
Author(s):  
Rabia Akan ◽  
Karolis Parfeniukas ◽  
Carmen Vogt ◽  
Muhammet S. Toprak ◽  
Ulrich Vogt
Keyword(s):  
Chemical Etching ◽  
X Ray ◽  
Zone Plates ◽  
Metal Assisted Chemical Etching ◽  
Silicon Based

scholarly journals Optimization of Metal-Assisted Chemical Etching for Deep Silicon Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2806
Author(s):  
Rabia Akan ◽  
Ulrich Vogt
Keyword(s):  
Aspect Ratio ◽  
Reaction Kinetics ◽  
Chemical Etching ◽  
Mechanical Stability ◽  
Zone Plate ◽  
Processing Temperature ◽  
Brick Wall ◽  
Wide Range ◽  
Metal Assisted Chemical Etching ◽  
Si Nanostructures

High-aspect ratio silicon (Si) nanostructures are important for many applications. Metal-assisted chemical etching (MACE) is a wet-chemical method used for the fabrication of nanostructured Si. Two main challenges exist with etching Si structures in the nanometer range with MACE: keeping mechanical stability at high aspect ratios and maintaining a vertical etching profile. In this work, we investigated the etching behavior of two zone plate catalyst designs in a systematic manner at four different MACE conditions as a function of mechanical stability and etching verticality. The zone plate catalyst designs served as models for Si nanostructures over a wide range of feature sizes ranging from 850 nm to 30 nm at 1:1 line-to-space ratio. The first design was a grid-like, interconnected catalyst (brick wall) and the second design was a hybrid catalyst that was partly isolated, partly interconnected (fishbone). Results showed that the brick wall design was mechanically stable up to an aspect ratio of 30:1 with vertical Si structures at most investigated conditions. The fishbone design showed higher mechanical stability thanks to the Si backbone in the design, but on the other hand required careful control of the reaction kinetics for etching verticality. The influence of MACE reaction kinetics was identified by lowering the oxidant concentration, lowering the processing temperature and by isopropanol addition. We report an optimized MACE condition to achieve an aspect ratio of at least 100:1 at room temperature processing by incorporating isopropanol in the etching solution.

scholarly journals High-efficiency zone-plate optics for multi-keV X-ray focusing

2014 ◽  
Vol 21 (3) ◽  
pp. 497-501 ◽  
Author(s):  
Istvan Mohacsi ◽  
Petri Karvinen ◽  
Ismo Vartiainen ◽  
Vitaliy A. Guzenko ◽  
Andrea Somogyi ◽  
...  
Keyword(s):  
Optical Transmission ◽  
High Efficiency ◽  
Fresnel Zone ◽  
Transmission Function ◽  
Zone Plate ◽  
X Rays ◽  
Fresnel Zone Plates ◽  
X Ray ◽  
Zone Plates ◽  
The Ideal

High-efficiency nanofocusing of hard X-rays using stacked multilevel Fresnel zone plates with a smallest zone width of 200 nm is demonstrated. The approach is to approximate the ideal parabolic lens profile with two-, three-, four- and six-level zone plates. By stacking binary and three-level zone plates with an additional binary zone plate, the number of levels in the optical transmission function was doubled, resulting in four- and six-level profiles, respectively. Efficiencies up to 53.7% focusing were experimentally obtained with 6.5 keV photons using a compact alignment apparatus based on piezoelectric actuators. The measurements have also been compared with numerical simulations to study the misalignment of the two zone plates.

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

2020 ◽  
Vol 5 (5) ◽  
pp. 869-879 ◽  
Author(s):  
Lucia Romano ◽  
Matias Kagias ◽  
Joan Vila-Comamala ◽  
Konstantins Jefimovs ◽  
Li-Ting Tseng ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Gas Phase ◽  
Chemical Etching ◽  
Pt Catalyst ◽  
Ray Optics ◽  
X Ray ◽  
Metal Assisted Chemical Etching

Gas-MacEtch of Si with a Pt catalyst allows vertical etching nanostructures with an extreme aspect ratio up to 10 000 : 1.

Germanium Phase Zone Plates with High Aspect Ratios for X-Ray Microscopy Experiments

1992 ◽  
pp. 83-86 ◽  
Author(s):  
J. Thieme ◽  
D. Rudolph ◽  
G. Schmahl ◽  
P. Guttmann ◽  
B. Greinke ◽  
...  
Keyword(s):  
Phase Zone ◽  
X Ray ◽  
Zone Plates ◽  
Aspect Ratios

Metal-Assisted Chemical Etching of Multicrystalline Silicon in HF/ Na2S2O8 Produces Porous Silicon

2005 ◽  
Vol 480-481 ◽  
pp. 139-144 ◽  
Author(s):  
T. Hadjersi ◽  
N. Gabouze ◽  
A. Ababou ◽  
M. Boumaour ◽  
W. Chergui ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Chemical Etching ◽  
Multicrystalline Silicon ◽  
Etching Time ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
External Bias ◽  
Etching Method ◽  
Metal Assisted Chemical Etching

A new metal-assisted chemical etching method using Na2S2O8 as an oxidant is proposed to form a porous layer on a multicrystalline silicon (mc-Si). This method does not need an external bias and enables formation of uniform porous silicon layers, more rapidly than the conventional stain etching method. A thin layer of Pd is deposited on the mc-Si surface prior to immersion in a solution of HF and Na2S2O8. The characterisations of etched layer formed by this method as a function of etching time were investigated by scanning electron microscopy, X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) and reflectance spectroscopy. It shows that the surface is porous and the etching is independent of grain orientation. In addition, reflectance measurements made with a variety of etching conditions show a lowering of the reflectance from 25 % to 6 % measured with respect to the bare as-cut substrate. However, this result can be improved by changing the experimental conditions (concentration, time, temperature, …).

scholarly journals Construction of Apodised Zone Plates for Solar X-Ray Image Formation

1971 ◽  
Vol 41 ◽  
pp. 207-210
Author(s):  
J. H. Dijkstra ◽  
W. De Graaff ◽  
L. J. Lantwaard
Keyword(s):  
Fresnel Zone ◽  
Image Formation ◽  
Zone Plate ◽  
Fresnel Zone Plate ◽  
X Ray ◽  
Zone Plates ◽  
Circular Rings

A Fresnel zone plate (sometimes called a Fresnel-Soret zone plate) is an image formation device consisting of a large number of concentric circular rings which are alternatively transparent and opaque for the radiation concerned.

scholarly journals Measurement and compensation of misalignment in double-sided hard X-ray Fresnel zone plates

2020 ◽  
Vol 27 (3) ◽  
pp. 583-589
Author(s):  
Viktoria Yurgens ◽  
Frieder Koch ◽  
Mario Scheel ◽  
Timm Weitkamp ◽  
Christian David
Keyword(s):  
Fresnel Zone ◽  
Back Side ◽  
Fresnel Zone Plates ◽  
X Ray ◽  
Zone Plates ◽  
Recording Efficiency ◽  
Aspect Ratios ◽  
Diffractive Lenses ◽  
Tilting Angle ◽  
Tungsten Anode

Double-sided Fresnel zone plates are diffractive lenses used for high-resolution hard X-ray microscopy. The double-sided structures have significantly higher aspect ratios compared with single-sided components and hence enable more efficient imaging. The zone plates discussed in this paper are fabricated on each side of a thin support membrane, and the alignment of the zone plates with respect to each other is critical. Here, a simple and reliable way of quantifying misalignments by recording efficiency maps and measuring the absolute diffraction efficiency of the zone plates as a function of tilting angle in two directions is presented. The measurements are performed in a setup based on a tungsten-anode microfocus X-ray tube, providing an X-ray energy of 8.4 keV through differential measurements with a Cu and an Ni filter. This study investigates the sources of the misalignments and concludes that they can be avoided by decreasing the structure heights on both sides of the membrane and by pre-programming size differences between the front- and back-side zone plates.

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