Three-dimensional compositional mapping using ion microscopy and volume-rendering techniques

Author(s):  
Richard W. Linton

Secondary ion mass spectrometry (SIMS), using ion microprobe or microscope instrumentation, couples lateral imaging and dynamic ion beam sputtering to provide 3-D compositional maps (image depth profiles). A data set acquired with an ion microscope may involve more than 100 massresolved ion images, each containing at least 64,000 pixels, with typical lateral and depth resolutions of 1 μm and 10 nm, respectively. The vast majority of prior quantitative surface analysis studies have addressed depth profiling, thin film, or overlayer measurements without the additional feature of laterally resolved imaging. The ability to create 3-D compositional maps using SIMS creates enormous challenges for quantification. In principle, each volume element requires individual calibration reflecting the combined effects of spatial resolution, sample heterogeneity, and variations in instrumental response. An overview of analytical considerations will be presented involving aspects of data acquisition, display, and processing, with a special emphasis on sector field mass spectrometers that provide high dynamic range image depth profiles.

Author(s):  
J.-J. Lee ◽  
J.L. Hunter ◽  
W.-J. Lin ◽  
R.W. Linton

Since the sample surface region is continuously sputtered in dynamic secondary ion mass spectrometry (SIMS), three dimensional (3D) chemical maps can be obtained by acquiring a series of two dimensional (2D) images. Owing to the limitations of the ion beam sputtering technique, SIMS analysis artifacts resulting from factors such as surface roughness, matrix effects, and atomic mixing are present in the 3D volume data. One potential advantage of using 3D display is to provide visual feedback regarding the elimination of artifacts by utilizing correction algorithms as well as correlative information obtained from other surface imaging techniques. In this paper, SIMS 3D maps are displayed by a volume rendering technique in which more information is retained in the image processing steps.Various 3D display methods have been proposed for SIMS and other microscopic imaging techniques. Some of the previous methods can not display the complete 3D spatial distribution of mass-selected ion intensities.


Chemosensors ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 246
Author(s):  
Alfio Torrisi ◽  
Jiří Vacík ◽  
Giovanni Ceccio ◽  
Antonino Cannavò ◽  
Vasily Lavrentiev ◽  
...  

Chemiresistors based on thin films of the Li-doped CuO–TiO2 heterojunctions were synthesized by a 2-step method: (i) repeated ion beam sputtering of the building elements (on the Si substrates and multisensor platforms); and (ii) thermal annealing in flowing air. The structure and composition of the films were analyzed by several methods: Rutherford Backscattering (RBS), Neutron Depth Profiling (NDP), Secondary Ion Mass Spectrometry (SIMS), and Atomic Force Microscopy (AFM), and their sensitivity to gaseous analytes was evaluated using a specific lab-made device operating in a continuous gas flow mode. The obtained results showed that the Li doping significantly increased the sensitivity of the sensors to oxidizing gases, such as NO2, O3, and Cl2, but not to reducing H2. The sensing response of the CuO–TiO2–Li chemiresistors improved with increasing Li content. For the best sensors with about 15% Li atoms, the detection limits were as follows: NO2 → 0.5 ppm, O3→ 10 ppb, and Cl2→ 0.1 ppm. The Li-doped sensors showed excellent sensing performance at a lower operating temperature (200 ∘C); however, even though their response time was only a few minutes, their recovery was slow (up to a few hours) and incomplete.


Author(s):  
Mark Denker ◽  
Jennifer Wall ◽  
Mark Ray ◽  
Richard Linton

Reactive ion beams such as O2+ and Cs+ are used in Secondary Ion Mass Spectrometry (SIMS) to analyze solids for trace impurities. Primary beam properties such as energy, dose, and incidence angle can be systematically varied to optimize depth resolution versus sensitivity tradeoffs for a given SIMS depth profiling application. However, it is generally observed that the sputtering process causes surface roughening, typically represented by nanometer-sized features such as cones, pits, pyramids, and ripples. A roughened surface will degrade the depth resolution of the SIMS data. The purpose of this study is to examine the relationship of the roughness of the surface to the primary ion beam energy, dose, and incidence angle. AFM offers the ability to quantitatively probe this surface roughness. For the initial investigations, the sample chosen was <100> silicon, and the ion beam was O2+.Work to date by other researchers typically employed Scanning Tunneling Microscopy (STM) to probe the surface topography.


2011 ◽  
Vol 148-149 ◽  
pp. 54-57
Author(s):  
Xiao Ping Lin ◽  
Yun Dong ◽  
Lian Wei Yang

The Al2O3 nano-films of different thicknesses (1~100nm) were successfully deposited on the monocrystalline Si surface by using ion beam sputtering deposition. The surface topography and the component of nano-films with different thickness were analyzed. The quality of the surface of nano-films was systematically studied. When the films’ thickness increase, the studies by atomic force microscope (AFM), X-ray photoelectron spectrum(XPS) show that the gathering grain continually grows up and transits from acerose cellula by two-dimensional growth to globularity by three-dimensional growth. The elements O, Al and Si were found on the surface of Al2O3 nano-films. With the thickness of the films increasing, the content of Al gradually increases and the intensity peak of Si wears off, the surface quality of the deposited films is ceaselessly improved


2001 ◽  
Vol 19 (10/12) ◽  
pp. 1303-1354 ◽  
Author(s):  
H. Rème ◽  
C. Aoustin ◽  
J. M. Bosqued ◽  
I. Dandouras ◽  
B. Lavraud ◽  
...  

Abstract. On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS) experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+) from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF), giving the mass per charge composition with medium (22.5°) angular resolution, and a Hot Ion Analyser (CIS2/HIA), which does not offer mass resolution but has a better angular resolution (5.6°) that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range. First tests of the instruments (commissioning activities) were achieved from early September 2000 to mid January 2001, and the operation phase began on 1 February 2001. In this paper, first results of the CIS instruments are presented showing the high level performances and capabilities of the instruments. Good examples of data were obtained in the central plasma sheet, magnetopause crossings, magnetosheath, solar wind and cusp measurements. Observations in the auroral regions could also be obtained with the Cluster spacecraft at radial distances of 4–6 Earth radii. These results show the tremendous interest of multispacecraft measurements with identical instruments and open a new area in magnetospheric and solar wind-magnetosphere interaction physics.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetopheric configuration and dynamics; solar wind - magnetosphere interactions)


Author(s):  
W. N. P. Hung ◽  
M. M. Agnihotri ◽  
M. Y. Ali ◽  
S. Yuan

Traditional micromanufacturing has been developed for semiconductor industry. Selected micro electrical mechanical systems (MEMS) have been successfully developed and implemented in industry. Since current MEMS are designed for manufacture using microelectronics processes, they are limited to two-dimensional profiles and semiconductor based materials. Such shape and material constraints would exclude many applications that require biocompatibility, dynamic stress, and high ductility. New technologies are sought to fabricate three dimensional microcomponents using robust materials for demanding applications. To be cost effective, such microdevices must be economically mass producible. Molding is one of the promising replication techniques to mass produce components from polymers and polymer-based composites. This paper presents the development of a micromolding process to produce thermoplastic microcomponents. Mold design required precision fitting and was integrated with a vacuum pump to minimize air trap in mold cavities. Nickel and aluminum mold inserts were used for the study; their cavities were fabricated by combinations of available micromachining processes like laser micromachining, micromilling, micro electrical discharge machining, and focused ion beam sputtering. High and low density polyethylene, polystyrene polymers were used for this study. The effects of polymer molecular structures, molding temperature, time, and pressure on molding results were studied. Simulation of stress in the microcomponents, plastic flow in microchannels, and mold defects was performed and compare with experimental data. The research results showed that a microcomponent can be fabricated to the minimum size of 10 ± 1μm (0.0004 inch) with surface roughness &lt;10 nm Rt. Molding of micro-size geartrains and orthopedic meso-size fasteners was completed to illustrate the capability of this process.


Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1250
Author(s):  
Darina Manova ◽  
Patrick Schlenz ◽  
Jürgen W. Gerlach ◽  
Stephan Mändl

Expanded austenite γN formed after nitrogen insertion into austenitic stainless steel and CoCr alloys is known as a hard and very wear resistant phase. Nevertheless, no single composition and lattice expansion can describe this phase with nitrogen in solid solution. Using in situ X-ray diffraction (XRD) during ion beam sputtering of expanded austenite allows a detailed depth-dependent phase analysis, correlated with the nitrogen depth profiles obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS) or glow discharge optical emission spectroscopy (GDOES). Additionally, in-plane XRD measurements at selected depths were performed for strain analysis. Surprisingly, an anomalous peak splitting for the (200) expanded peak was observed for some samples during nitriding and sputter etching, indicating a layered structure only for {200} oriented grains. The strain analysis as a function of depth and orientation of scattering vector (parallel/perpendicular to the surface) is inconclusive.


2009 ◽  
Vol 15 (3) ◽  
pp. 216-219 ◽  
Author(s):  
Hee Jae Kang ◽  
Dae Won Moon ◽  
Hyung-Ik Lee

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