scholarly journals Insights into secondary ion formation during dynamic SIMS analysis: Evidence from sputtering of laboratory synthesized uranium compounds with a high-energy O− primary beam on a NanoSIMS 50L

2021 ◽  
Vol 502 ◽  
pp. 164-175
Author(s):  
N. Alex Zirakparvar ◽  
Tyler L. Spano ◽  
Andrew Miskowiec ◽  
Julie B. Smith ◽  
Cole R. Hexel ◽  
...  
Keyword(s):  
High Energy ◽  
Primary Beam ◽  
Ion Formation ◽  
Uranium Compounds ◽  
Sims Analysis ◽  
Secondary Ion

scholarly journals A NanoSIMS 50 L Investigation into Improving the Precision and Accuracy of the 235U/238U Ratio Determination by Using the Molecular 235U16O and 238U16O Secondary Ions

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 307 ◽  
Author(s):  
N. Zirakparvar ◽  
Cole Hexel ◽  
Andrew Miskowiec ◽  
Julie Smith ◽  
Michael Ambrogio ◽  
...  
Keyword(s):  
Reference Materials ◽  
The Other ◽  
Primary Beam ◽  
Uranium Compounds ◽  
Accuracy And Precision ◽  
Secondary Ions ◽  
Precision And Accuracy ◽  
Improved Accuracy ◽  
Secondary Ion ◽  
238U Ratio

A NanoSIMS 50 L was used to study the relationship between the 235U/238U atomic and 235U16O/238U16O molecular uranium isotope ratios determined from a variety of uranium compounds (UO2, UO2F2, UO3, UO2(NO3)2·6(H2O), and UF4) and silicates (NIST-610 glass and the Plesovice zircon reference materials, both containing µg/g uranium). Because there is typically a greater abundance of 235U16O+ and 238U16O+ molecular secondary ions than 235U+ and 238U+ atomic ions when uranium-bearing materials are sputtered with an oxygen primary ion beam, the goal was to understand whether use of 235U16O/238U16O has the potential for improved accuracy and precision when compared to the 235U/238U ratio. The UO2 and silicate reference materials showed the greatest potential for improved accuracy and precision through use of the 235U16O/238U16O ratio as compared to the 235U/238U ratio. For the UO2, which was investigated at a variety of primary beam currents, and the silicate reference materials, which were only investigated using a single primary beam current, this improvement was especially pronounced at low 235U+ count rates. In contrast, comparison of the 235U16O/238U16O ratio versus the 235U/238U ratio from the other uranium compounds clearly indicates that the 235U16O/238U16O ratio results in worse precision and accuracy. This behavior is based on the observation that the atomic (235U+ and 238U+) to molecular (235U16O+ and 238U16O+) secondary ion production rates remain internally consistent within the UO2 and silicate reference materials, whereas it is highly variable in the other uranium compounds. Efforts to understand the origin of this behavior suggest that irregular sample surface topography, and/or molecular interferences arising from the manner in which the UO2F2, UO3, UO2(NO3)2·6(H2O), and UF4 were prepared, may be a major contributing factor to the inconsistent relationship between the observed atomic and molecular secondary ion yields. Overall, the results suggest that for certain bulk compositions, use of the 235U16O/238U16O may be a viable approach to improving the precision and accuracy in situations where a relatively low 235U+ count rate is expected.

Depth Profiles of High-energy Recoil Implantation of Boron into Silicon

2000 ◽  
Vol 610 ◽  
Author(s):  
Lin Shao ◽  
Xinming Lu ◽  
Jianyue Jin ◽  
Qinmian Li ◽  
Irene Rusakova ◽  
...  
Keyword(s):  
Ion Beam ◽  
High Energy ◽  
Implantation Energy ◽  
Strong Function ◽  
Recoil Implantation ◽  
Depth Profiles ◽  
Calculation Results ◽  
Energy Incident ◽  
Sims Analysis ◽  
Secondary Ion

AbstractWe have studied boron profiles by using the ion beam recoil implantation. A boron layer was first deposited onto Si, followed by irradiation with Si ions at various energies to knock the boron. Conventional belief is that the higher the implantation energy, the deeper the recoil profiles. While this is true for low-energy incident ions, we show here that the situation is reversed for incident Si ions of higher energy due to the fact that recoil probability at a given angle is a strong function of the energy of the primary projectile. Our experiments show that 500-keV high-energy recoil implantation produces a shallower B profile than lower-energy implantation such as 10 keV and 50 keV. The secondary-ion-massspectrometry (SIMS) analysis shows that the distribution of recoiled B atoms scattered by the energetic Si ions agrees with our calculation results. Sub-100 nm p+/n junctions have been realized with a 500-keV Si ion beam.

Compact back-scattered electrons' energy analyzer for standard SEM

1994 ◽  
Vol 52 ◽  
pp. 488-489
Author(s):  
S. Likharev ◽  
A. Kramarenko ◽  
V. Vybornov
Keyword(s):  
Depth Resolution ◽  
High Energy ◽  
Primary Beam ◽  
Layer By Layer ◽  
Energy Analyzer ◽  
High Energy Part ◽  
Small Window ◽  
Energy Part ◽  
Wide Range ◽  
High Voltage Supply

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.

An Effective SIMS Methodology for GOI Contamination Analysis

2013 ◽  
Author(s):  
Yanhua Huang ◽  
Lei Zhu ◽  
Kenny Ong ◽  
Hanwei Teo ◽  
Younan Hua
Keyword(s):  
Oxide Layer ◽  
Secondary Ion Mass Spectrometry ◽  
Gate Oxide ◽  
Sample Surface ◽  
Low Energy ◽  
Cross Contamination ◽  
Common Effect ◽  
Sims Analysis ◽  
Secondary Ion ◽  
Lower Background

Abstract Contamination in the gate oxide layer is the most common effect which cause the gate oxide integrate (GOI) issue. Dynamic Secondary Ion Mass Spectrometry (SIMS) is a mature tool for GOI contamination analysis. During the sample preparation, all metal and IDL layers above poly should be removed because the presence of these layers added complexity for the subsequent SIMS analysis. The normal delayering process is simply carried out by soaking the sample in the HF solution. However, the poly surface is inevitably contaminated by surroundings even though it is already a practice to clean with DI rinse and tape. In this article, TOFSIMS with low energy sputter gun is used to clean the sample surface after the normal delayering process. The residue signals also can be monitored by TOF SIMS during sputtering to confirm the cross contamination is cleared. After that, a much lower background desirable by dynamic SIMS. Thus an accurate depth profile in gate oxide layer can be achieved without the interference from surface.

Hb Neuilly-Sur-Marne, a New Human Hemoglobin Variant with Ser-Asp-Leu Inserted between α86(F7) Leu and α87(F8) His: Characterization by High-Energy Collision-Induced Dissociation Liquid Secondary Ion Mass Spectrometry and Low Energy Collision-Induced Dissociation Tandem Mass Spectrometry in An Ion Trap Fitted with a Nanospray Ionization Source

2000 ◽  
Vol 6 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Danielle Promé ◽  
Jean-Claude Promé ◽  
Henri Wajcman ◽  
Jean Riou ◽  
Frédéric Galactéros ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Ion Trap ◽  
High Energy ◽  
Sequence Information ◽  
Energy Collision ◽  
Ionization Source ◽  
Nanospray Ionization ◽  
Singly Charged ◽  
Secondary Ion

Hemoglobin (Hb) Neuilly-sur-Marne is a new α-chain variant found during a systematic screening. Electrospray mass measurements showed the presence of an abnormal α-chain displaying a shift of +315 u relative to the normal value. Tryptic cleavage of this chain and molecular weight determination of the peptides indicated that the 315 u shift was located into the αT-9 peptide, the molecular weight of which is higher than 3000 Da. High-energy collision spectra of MH+ ions generated by liquid secondary ion mass spectrometry from the normal and abnormal αT-9 afforded mainly amino-terminal containing ions. They indicated that these two peptides have an identical amino acid sequence from their 1st to 25th residues, the mass increase being thus located beyond this point. Too few ions were formed to establish reliably the sequence forward. It was hypothesized that this mass shift could result from a repeated sequence since the sum of the mass of the three residues—leucine, serine and aspartic acid—preceding position 25 is exactly 315 u. To get sequence information above position 25, decomposition of multicharged species was attempted. An ion trap fitted with a nanospray ionization source was used. It produced mainly triply- and quadruply-charged ions. Decomposition of the triply-charged ion afforded a series of singly-charged Y-ions in the expected region, giving a readily interpretable sequence. It confirmed the insertion of a Ser-Asp-Leu sequence above position 25. Surprisingly, decomposition of the quadruply-charged molecular ion gave too few ions to provide sequence information in the expected region. Spectra were dominated by some multicharged Y ions arising from cleavages close to the amino end. Tandem mass spectrometry experiments were performed on the abundant Y303+ ion and produced again a singly-charged Y ion series in the suitable domain which confirmed the above result. In Hb Neuilly-sur Marne this insertion of the Ser-Asp-Leu residues. between positions α-86 and α-87 is very likely due to a slipped strand mispairing mechanism.

Molecular secondary ion formation and H/D exchange in amino acid-metal systems

1987 ◽  
Vol 182 (3) ◽  
pp. A145
Author(s):  
M. Jirikowsky ◽  
D. Holtkamp ◽  
P. Klüsener ◽  
M. Kempken ◽  
A. Benninghoven
Keyword(s):  
Amino Acid ◽  
Ion Formation ◽  
Secondary Ion

scholarly journals Applications of ToF-SIMS in surface chemistry analysis of lignocellulosic biomass: A review

BioResources ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. 5581-5599
Author(s):  
Hong Yan Mou ◽  
Shubin Wu ◽  
Pedro Fardim
Keyword(s):  
Surface Chemistry ◽  
Lignocellulosic Biomass ◽  
Secondary Ion Mass Spectrometry ◽  
Critical Factor ◽  
Tof Sims ◽  
Biomass Components ◽  
Current Article ◽  
Sims Analysis ◽  
Secondary Ion

Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) is an advanced surface-sensitive technique that can provide both spectral and imaging information about materials. Recently, ToF-SIMS has been used for advanced studies of lignocellulosic biomass. In the current article, the application of ToF-SIMS to the characterization of the surface chemical composition and distribution of biomass components in lignocelluloses is reviewed. Moreover, extended applications of ToF-SIMS in the study of pretreatments, modification of biomaterials, and enzyme activity of lignocellulosic materials are presented and discussed. Sample preparation prior to ToF-SIMS analysis and subsequent interpretation of results is a critical factor in ensuring reliable results. The focus of this review is to give a comprehensive understanding of and offer new hints about the effects of processing conditions on the surface chemistry of lignocellulosic biomass.

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