scholarly journals Origin of the enhanced Nb3Sn performance by combined Hf and Ta doping

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chiara Tarantini ◽  
Fumitake Kametani ◽  
Shreyas Balachandran ◽  
Steve M. Heald ◽  
Laura Wheatley ◽  
...  
Keyword(s):  
High Field ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Field Performance ◽  
Atom Probe ◽  
Pinning Force ◽  
Critical Fields ◽  
Thin Lamella ◽  
X Ray Absorption ◽  
Ta Doping

AbstractIn recent years there has been an increasing effort in improving the performance of Nb3Sn for high-field applications, in particular for the fabrication of conductors suitable for the realization of the Future Circular Collider (FCC) at CERN. This challenging task has led to the investigation of new routes to advance the high-field pinning properties, the irreversibility and the upper critical fields (HIrr and Hc2, respectively). The effect of hafnium addition to the standard Nb-4Ta alloy has been recently demonstrated to be particularly promising and, in this paper, we investigate the origins of the observed improvements of the superconducting properties. Electron microscopy, Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS) and Atom Probe Tomography (APT) characterization clearly show that, in presence of oxygen, both fine Nb3Sn grains and HfO2 nanoparticles form. Although EXAFS is unable to detect significant amounts of Hf in the A15 structure, APT does indeed reveal some residual intragrain metallic Hf. To investigate the layer properties in more detail, we created a microbridge from a thin lamella extracted by Focused Ion Beam (FIB) and measured the transport properties of Ta-Hf-doped Nb3Sn. Hc2(0) is enhanced to 30.8 T by the introduction of Hf, ~ 1 T higher than those of only Ta-doped Nb3Sn, and, even more importantly the position of the pinning force maximum exceeds 6 T, against the typical ~ 4.5–4.7 T of the only Ta-doped material. These results show that the improvements generated by Hf addition can significantly enhance the high-field performance, bringing Nb3Sn closer to the requirements necessary for FCC realization.

scholarly journals Three-Dimensional Nanoscale Mapping of State-of-the-Art Field-Effect Transistors (FinFETs)

2017 ◽  
Vol 23 (5) ◽  
pp. 916-925
Author(s):  
Pritesh Parikh ◽  
Corey Senowitz ◽  
Don Lyons ◽  
Isabelle Martin ◽  
Ty J. Prosa ◽  
...  
Keyword(s):  
Field Effect ◽  
Focused Ion Beam ◽  
Field Effect Transistors ◽  
Ion Beam ◽  
Semiconductor Industry ◽  
Three Dimensional ◽  
Atom Probe ◽  
Physical Structure ◽  
Oxide Semiconductor ◽  
Device Performance

AbstractThe semiconductor industry has seen tremendous progress over the last few decades with continuous reduction in transistor size to improve device performance. Miniaturization of devices has led to changes in the dopants and dielectric layers incorporated. As the gradual shift from two-dimensional metal-oxide semiconductor field-effect transistor to three-dimensional (3D) field-effect transistors (finFETs) occurred, it has become imperative to understand compositional variability with nanoscale spatial resolution. Compositional changes can affect device performance primarily through fluctuations in threshold voltage and channel current density. Traditional techniques such as scanning electron microscope and focused ion beam no longer provide the required resolution to probe the physical structure and chemical composition of individual fins. Hence advanced multimodal characterization approaches are required to better understand electronic devices. Herein, we report the study of 14 nm commercial finFETs using atom probe tomography (APT) and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS). Complimentary compositional maps were obtained using both techniques with analysis of the gate dielectrics and silicon fin. APT additionally provided 3D information and allowed analysis of the distribution of low atomic number dopant elements (e.g., boron), which are elusive when using STEM-EDS.

Automated Sample Depth Targeting with Low kV Cleaning by Focused Ion Beam Microscopy for Atom Probe Tomography

2020 ◽  
Author(s):  
Woo Jun Kwon ◽  
Jisu Ryu ◽  
Christopher H. Kang ◽  
Michael B. Schmidt ◽  
Nicholas Croy
Keyword(s):  
Sample Preparation ◽  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Region Of Interest ◽  
Atom Probe ◽  
Sample Volume ◽  
Cleaning Process ◽  
Site Specific ◽  
Sample Depth

Abstract Focused ion beam (FIB) microscopy is an essential technique for the site-specific sample preparation of atom probe tomography (APT). The site specific APT and automated APT sample preparation by FIB have allowed increased APT sample volume. In the workflow of APT sampling, it is very critical to control depth of the sample where exact region of interest (ROI) for accurate APT analysis. Very precise depth control is required at low kV cleaning process in order to remove the damaged layer by previous high kV FIB process steps. We found low kV cleaning process with 5 kV and followed by 2kV beam conditions delivers better control to reached exact ROI on Z direction. This understanding is key to make APT sample with fully automated fashion.

scholarly journals Practical Issues for Atom Probe Tomography Analysis of III-Nitride Semiconductor Materials

2015 ◽  
Vol 21 (3) ◽  
pp. 544-556 ◽  
Author(s):  
Fengzai Tang ◽  
Michael P. Moody ◽  
Tomas L. Martin ◽  
Paul A.J. Bagot ◽  
Menno J. Kappers ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Laser Energy ◽  
Ion Beam ◽  
Atom Probe ◽  
Specimen Preparation ◽  
Chemical Compositions ◽  
Pole Structure ◽  
Gan Heterostructure ◽  
Ga Content

AbstractVarious practical issues affecting atom probe tomography (APT) analysis of III-nitride semiconductors have been studied as part of an investigation using a c-plane InAlN/GaN heterostructure. Specimen preparation was undertaken using a focused ion beam microscope with a mono-isotopic Ga source. This enabled the unambiguous observation of implantation damage induced by sample preparation. In the reconstructed InAlN layer Ga implantation was demonstrated for the standard “clean-up” voltage (5 kV), but this was significantly reduced by using a lower voltage (e.g., 1 kV). The characteristics of APT data from the desorption maps to the mass spectra and measured chemical compositions were examined within the GaN buffer layer underlying the InAlN layer in both pulsed laser and pulsed voltage modes. The measured Ga content increased monotonically with increasing laser pulse energy and voltage pulse fraction within the examined ranges. The best results were obtained at very low laser energy, with the Ga content close to the expected stoichiometric value for GaN and the associated desorption map showing a clear crystallographic pole structure.

On the Precision Preparation of Samples for Atom Probe Tomography Using a Focused Ion Beam in a SEM

2018 ◽  
Vol 12 (1) ◽  
pp. 87-93 ◽  
Author(s):  
V. V. Khoroshilov ◽  
O. A. Korchuganova ◽  
A. A. Lukyanchuk ◽  
O. A. Raznitsyn ◽  
A. A. Aleev ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atom Probe

scholarly journals Laser-assisted atom probe tomography of semiconductors: The impact of the focused-ion beam specimen preparation

2018 ◽  
Vol 188 ◽  
pp. 19-23 ◽  
Author(s):  
J. Bogdanowicz ◽  
A. Kumar ◽  
C. Fleischmann ◽  
M. Gilbert ◽  
J. Houard ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atom Probe ◽  
Beam Specimen ◽  
Specimen Preparation ◽  
The Impact

Electron Beam-Induced Deposition for Atom Probe Tomography Specimen Capping Layers

2016 ◽  
Vol 23 (2) ◽  
pp. 321-328 ◽  
Author(s):  
David R. Diercks ◽  
Brian P. Gorman ◽  
Johannes J. L. Mulders
Keyword(s):  
Electron Beam ◽  
Atom Probe Tomography ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atom Probe ◽  
Near Surface ◽  
Surface Features ◽  
Dicobalt Octacarbonyl ◽  
Electron Beam Induced Deposition

AbstractSix precursors were evaluated for use as in situ electron beam-induced deposition capping layers in the preparation of atom probe tomography specimens with a focus on near-surface features where some of the deposition is retained at the specimen apex. Specimens were prepared by deposition of each precursor onto silicon posts and shaped into sub-70-nm radii needles using a focused ion beam. The utility of the depositions was assessed using several criteria including composition and uniformity, evaporation behavior and evaporation fields, and depth of Ga+ ion penetration. Atom probe analyses through depositions of methyl cyclopentadienyl platinum trimethyl, palladium hexafluoroacetylacetonate, and dimethyl-gold-acetylacetonate [Me2Au(acac)] were all found to result in tip fracture at voltages exceeding 3 kV. Examination of the deposition using Me2Au(acac) plus flowing O2 was inconclusive due to evaporation of surface silicon from below the deposition under all analysis conditions. Dicobalt octacarbonyl [Co2(CO)8] and diiron nonacarbonyl [Fe2(CO)9] depositions were found to be effective as in situ capping materials for the silicon specimens. Their very different evaporation fields [36 V/nm for Co2(CO)8 and 21 V/nm for Fe2(CO)9] provide options for achieving reasonably close matching of the evaporation field between the capping material and many materials of interest.

scholarly journals Focused ion beam preparation of atom probe specimens containing a single crystallographically well-defined grain boundary

Micron ◽  
2008 ◽  
Vol 39 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Fabián Pérez-Willard ◽  
Daniel Wolde-Giorgis ◽  
Talaát Al-Kassab ◽  
Gabriel A. López ◽  
Eric J. Mittemeijer ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Atom Probe
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