scholarly journals Artifacts from manganese reduction in rock samples prepared by focused ion beam (FIB) slicing for X-ray microspectroscopic analysis

2018 ◽  
Author(s):  
Dorothea S. Macholdt ◽  
Christopher Pöhlker ◽  
Jan-David Förster ◽  
Maren Müller ◽  
Bettina Weber ◽  
...  

Abstract. Manganese (Mn)-rich natural rock coatings, so-called rock varnishes, are discussed controversially regarding their genesis. Biogenic and abiogenic mechanisms, as well as a combination of both, have been proposed to be responsible for the Mn oxidation and deposition process. We conducted scanning transmission X-ray microscopy - near edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS) measurements to examine the abundance and spatial distribution of the different oxidation states of Mn within these nano- to micrometer thick crusts. Such microanalytical measurements of thin and hard rock crusts require sample preparation with minimal contamination risk. Focused ion beam (FIB) slicing, a well-established technique in geosciences, was used in this study to obtain 100–200 nm thin slices of the samples for X-ray transmission spectroscopy. However, even though this preparation is suitable to investigate element distributions and structures in rock samples, we observed that, using standard parameters, modifications of the Mn oxidation states occur in the surfaces of the FIB slices. Based on our results, the preparation technique likely causes the reduction of Mn4+ to Mn2+/3+. We draw attention to this issue, since FIB slicing, SEM imaging, and other preparation and visualization techniques operating in the keV range are well-established in geosciences, but researchers are often unaware of the potential for reduction of Mn and possibly other elements in the samples’ surface layers.

2019 ◽  
Vol 8 (1) ◽  
pp. 97-111
Author(s):  
Dorothea S. Macholdt ◽  
Jan-David Förster ◽  
Maren Müller ◽  
Bettina Weber ◽  
Michael Kappl ◽  
...  

Abstract. The spatial distribution of transition metal valence states is of broad interest in the microanalysis of geological and environmental samples. An example is rock varnish, a natural manganese (Mn)-rich rock coating, whose genesis mechanism remains a subject of scientific debate. We conducted scanning transmission X-ray microscopy with near-edge X-ray absorption fine-structure spectroscopy (STXM-NEXAFS) measurements of the abundance and spatial distribution of different Mn oxidation states within the nano- to micrometer thick varnish crusts. Such microanalytical measurements of thin and hard rock crusts require sample preparation with minimal contamination risk. Focused ion beam (FIB) slicing was used to obtain ∼100–1000 nm thin wedge-shaped slices of the samples for STXM, using standard parameters. However, while this preparation is suitable for investigating element distributions and structures in rock samples, we observed artifactual modifications of the Mn oxidation states at the surfaces of the FIB slices. Our results suggest that the preparation causes a reduction of Mn4+ to Mn2+. We draw attention to this issue, since FIB slicing, scanning electron microscopy (SEM) imaging, and other preparation and visualization techniques operating in the kilo-electron-volt range are well-established in geosciences, but researchers are often unaware of the potential for the reduction of Mn and possibly other elements in the samples.


Author(s):  
T. Yaguchi ◽  
M. Konno ◽  
T. Kamino ◽  
M. Ogasawara ◽  
K. Kaji ◽  
...  

Abstract A technique for preparation of a pillar shaped sample and its multi-directional observation of the sample using a focused ion beam (FIB) / scanning transmission electron microscopy (STEM) system has been developed. The system employs an FIB/STEM compatible sample rotation holder with a specially designed rotation mechanism, which allows the sample to be rotated 360 degrees [1-3]. This technique was used for the three dimensional (3D) elemental mapping of a contact plug of a Si device in 90 nm technology. A specimen containing a contact plug was shaped to a pillar sample with a cross section of 200 nm x 200 nm and a 5 um length. Elemental analysis was performed with a 200 kV HD-2300 STEM equipped with the EDAX genesis Energy dispersive X-ray spectroscopy (EDX) system. Spectrum imaging combined with multivariate statistical analysis (MSA) [4, 5] was used to enhance the weak X-ray signals of the doped area, which contain a low concentration of As-K. The distributions of elements, especially the dopant As, were successfully enhanced by MSA. The elemental maps were .. reconstructed from the maps.


1995 ◽  
Vol 396 ◽  
Author(s):  
P.G. Blauner ◽  
A. Wagner

AbstractThe ion beam induced metal deposition processes now employed by commercial focused ion beam (FIB) tools all demonstrate less than optimal characteristics for use in circuit repair, a major application of these tools. In particular, the processes have low efficiencies, the metals produced have poor conductivity, and some form of clean up is generally required to remove excess material surrounding the repair site. The gold deposition process developed for x-ray mask repair, in contrast, exhibits efficiencies 10-50 times higher with significantly less material deposited in unwanted areas. Unfortunately, the conductivity of the gold is even poorer than that of materials now used for FIB circuit repair.In this paper, an annealing step which improves the conductivity of FIB deposited Au is described. Results are presented demonstrating resistivities of 5-15 μΩ-cm while maintaining the high efficiency of the gold deposition process. The suitability of the process for use in FIB circuit repair is discussed.


2020 ◽  
Author(s):  
Motoo Ito ◽  
Naotaka Tomioka ◽  
Kentaro Uesugi ◽  
Masayuki Uesugi ◽  
Yu Kodama ◽  
...  

Abstract We developed universal sample holders (the Kochi grid, Kochi clamp, and Okazaki cell) and a transfer vessel (facility-to-facility transfer container (FFTC)) to analyze sensitive and fragile samples, such as extremely small extraterrestrial materials. The holders and container prevent degradation, contamination due to terrestrial atmosphere (water vapor and oxygen gas) and small particles, as well as mechanical sample damages. The FFTC can isolate the samples from the effects of the atmosphere for more than a week. The Kochi grid and clamp were made for a coordinate micro/nano-analysis that utilize a focused-ion beam apparatus, transmission electron microscope, and nanoscale secondary ion mass spectrometry. The Okazaki cell was made as an additional attachment for a scanning transmission X-ray microscope that uses near edge X-ray absorption fine structure. The coordinated analysis involving these holders was successfully carried out without any sample damage or loss, thereby enabling us to obtain sufficient quality of analytical datasets of textures, crystallography, elemental/isotopic abundances, and molecular functional groups for µm-sized minerals and organics in both an Antarctic micrometeorite and a carbonaceous chondrite. We will apply the coordinated analysis to acquire the complex characteristics in samples that obtain by the future spacecraft sample return mission.


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 546
Author(s):  
Sina Mayr ◽  
Simone Finizio ◽  
Joakim Reuteler ◽  
Stefan Stutz ◽  
Carsten Dubs ◽  
...  

We employ xenon (Xe) plasma focused ion beam (PFIB) milling to obtain soft X-ray transparent windows out of bulk samples. The use of a Xe PFIB allows for the milling of thin windows (several 100 nm thick) with areas of the order of 100 µm × 100 µm into bulk substrates. In addition, we present an approach to empirically determine the transmission level of such windows during fabrication by correlating their electron and soft X-ray transparencies. We perform scanning transmission X-ray microscopy (STXM) imaging on a sample obtained by Xe PFIB milling to demonstrate the conceptual feasibility of the technique. Our thinning approach provides a fast and simplified method for facilitating soft X-ray transmission measurements of epitaxial samples and it can be applied to a variety of different sample systems and substrates that are otherwise not accessible.


2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Motoo Ito ◽  
Naotaka Tomioka ◽  
Kentaro Uesugi ◽  
Masayuki Uesugi ◽  
Yu Kodama ◽  
...  

Abstract We developed universal sample holders [the Kochi grid, Kochi clamp, and Okazaki cell) and a transfer vessel (facility-to-facility transfer container (FFTC)] to analyze sensitive and fragile samples, such as extremely small extraterrestrial materials. The holders and container prevent degradation, contamination due to the terrestrial atmosphere (water vapor and oxygen gas) and small particles, as well as mechanical sample damage. The FFTC can isolate the samples from the effects of the atmosphere for more than a week. The Kochi grid and clamp were made for a coordinated micro/nano-analysis that utilizes a focused-ion beam apparatus, transmission electron microscope, and nanoscale secondary ion mass spectrometry. The Okazaki cell was developed as an additional attachment for a scanning transmission X-ray microscope that uses near-edge X-ray absorption fine structure (NEXAFS). These new apparatuses help to minimize possible alterations from the exposure of the samples to air. The coordinated analysis involving these holders was successfully carried out without any sample damage or loss, thereby enabling us to obtain sufficient analytical datasets of textures, crystallography, elemental/isotopic abundances, and molecular functional groups for µm-sized minerals and organics in both the Antarctic micrometeorite and a carbonaceous chondrite. We will apply the coordinated analysis to acquire the complex characteristics in samples obtained by the future spacecraft sample return mission.


2020 ◽  
Author(s):  
Motoo Ito ◽  
Naotaka Tomioka ◽  
Kentaro Uesugi ◽  
Masayuki Uesugi ◽  
Yu Kodama ◽  
...  

Abstract We developed universal sample holders (the Kochi grid, Kochi clamp, and Okazaki cell) and a transfer vessel (facility-to-facility transfer container (FFTC)) to analyze sensitive and fragile samples, such as extremely small extraterrestrial materials. The holders and container prevent degradation, contamination due to terrestrial atmosphere (water vapor and oxygen gas) and small particles, as well as mechanical sample damages. The FFTC can isolate the samples from the effects of the atmosphere for more than a week. The Kochi grid and clamp were made for a coordinate micro/nano-analysis that utilize a focused-ion beam apparatus, transmission electron microscope, and nanoscale secondary ion mass spectrometry. The Okazaki cell was made as an additional attachment for a scanning transmission X-ray microscope that uses near edge X-ray absorption fine structure. The coordinated analysis involving these holders was successfully carried out without any sample damage or loss, thereby enabling us to obtain sufficient quality of analytical datasets of textures, crystallography, elemental/isotopic abundances, and molecular functional groups for µm-sized minerals and organics in both an Antarctic micrometeorite and a carbonaceous chondrite. We will apply the coordinated analysis to acquire the complex characteristics in samples that obtain by the future spacecraft sample return mission.


2020 ◽  
Author(s):  
Motoo Ito ◽  
Naotaka Tomioka ◽  
Kentaro Uesugi ◽  
Masayuki Uesugi ◽  
Yu Kodama ◽  
...  

Abstract We developed universal sample holders (the Kochi grid, Kochi clamp, and Okazaki cell) and a transfer vessel (facility-to-facility transfer container (FFTC)) to analyze sensitive and fragile samples, such as extremely small extraterrestrial materials. The holders and container prevent degradation, contamination due to the terrestrial atmosphere (water vapor and oxygen gas) and small particles, as well as mechanical sample damage. The FFTC can isolate the samples from the effects of the atmosphere for more than a week. The Kochi grid and clamp were made for a coordinated micro/nano-analysis that utilizes a focused-ion beam apparatus, transmission electron microscope, and nanoscale secondary ion mass spectrometry. The Okazaki cell was developed as an additional attachment for a scanning transmission X-ray microscope that uses near-edge X-ray absorption fine structure (NEXAFS). These new apparatuses help to minimize possible alterations from the exposure of the samples to air. The coordinated analysis involving these holders was successfully carried out without any sample damage or loss, thereby enabling us to obtain sufficient analytical datasets of textures, crystallography, elemental/isotopic abundances, and molecular functional groups for µm-sized minerals and organics in both the Antarctic micrometeorite and a carbonaceous chondrite. We will apply the coordinated analysis to acquire the complex characteristics in samples obtained by the future spacecraft sample return mission.


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