bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Solution Processing and Device Integration of Two-Dimensional Black Phosphorus
Authors: Hersam Mark C. 
Published: February 2020

Two-dimensional black phosphorus (2D BP) has emerged as a promising candidate for next-generation electronics and optoelectronics. As is common for new materials, much of the early work on 2D BP has focused on measuring and optimizing intrinsic properties on small samples under idealized conditions. However, real-world devices and systems inevitably require large-area samples that are integrated with dielectrics, contacts, and other semiconductors at standard temperature and pressure conditions. These requirements are particularly challenging to realize for 2D BP since its properties are highly sensitive to surface chemistry, defects, and the surrounding environment. This talk will thus explore methods for improving the uniformity of solution-based 2D BP with an eye toward realizing scalable processing of large-area thin-films. Specifically, methods for exfoliating black phosphorus in anhydrous organic solvents will be discussed such that the resulting 2D BP flakes show field-effect transistor mobilities and on/off ratios that are comparable to micromechanically exfoliated flakes [1]. In addition to solution processing, this talk will also report on the integration of 2D BP with dielectrics and other materials. In particular, atomic layer deposition of alumina dielectrics on 2D BP suppresses ambient degradation, thereby preserving electronic properties in field-effect transistors at atmospheric pressure conditions [2].
[1] J. Kang, J. D. Wood, S. A. Wells, J.-H. Lee, X. Liu, K.-S. Chen, and M. C. Hersam, “Solvent exfoliation of electronic-grade, two-dimensional black phosphorus,” ACS Nano, DOI: 10.1021/acsnano.5b01143 (2015).
[2] J. D. Wood, S. A. Wells, D. Jariwala, K.-S. Chen, E. Cho, V. K. Sangwan, X. Liu, L. J. Lauhon, T. J. Marks, and M. C. Hersam, “Effective passivation of exfoliated black phosphorus transistors against ambient degradation,” Nano Lett., 14, 6964 (2014).
Extreme Bottom-up in Through Silicon Vias by Leveler Pre-adsorption
Authors: Ishii Takao , Egoshi Haruki , Hayase Masanori 
Published: February 2020

In the TSV copper filling process, combination of several additives, such as suppressor, accelerator and levelers, are used in the electroplating bath. Besides, strong agitation is often applied to achieve good bottom-up feature. From past studies, it is considered that levelers, which show strong suppression effect in the electroplating, have an essential role in the bottom-up feature. It is assumed that the bottom-up TSV filling is achieved based on diffusion-adsorption model, in which less suppression in the via bottom is caused by diffusional limitation of the leveler and preferential deposition happens around via bottom. However, in the practical filling process, in addition to the leveler, other additives are used, and the filling mechanism is not clear yet. In this study, only leveler is added in the plating bath, and the effect of leveler on filling feature is discussed.

Experimental

The leveler used in this study is a commercial product,and the composition is not opened. Besides, the product name is neither provided. At first, in order to grasp the suppression effect of the leveler, chronoamperometry was carried out with addition of only leveler in an acid copper sulfate plating bath ( 1M CuSO4 + 0.3 M H2SO4+ 1mM HCl ). It was assumed that initial adsorption of the leveler on plating surface has some impacts, and pre-immersion time before the plating start was varied. -520mV vs. MSE was applied with a rotating disk electrode at a rotational speed of 400rpm. Leveler concentrations of manufacture’s standard (x1) and 5 times concentrated one (x5) were examined. Figure 1 shows the results. Strong suppression was not obtained with standard leveler concentration, and suppression became stronger along plating time. Less current density at initial plating period was observed with longer pre-immersion. Stronger suppression was observed with 5x leveler concentration. From these results, it was supposed that suppression is limited by mass transfer of leveler. In order to clarify the diffusion-adsorption effect, TSV filling experiment with pre-immersion was performed. Figure 2 shows example results. With short pre-immersion, it is supposed that little leveler adsorbed inside the via, while strong suppression was observed on upper area of the via with 30min pre-immersion, and it was found that the leveler diffused deeper with long pre-immersion. Figure 3 shows an example result after some optimization. Extreme bottom-up was achieved with relatively high aspect ratio vias.

Figure 1
Dielectric Spectroscopic Detection of Early Failures in 3-D Integrated Circuits
Authors: Obeng Yaw S. , Okoro Chukwudi A. , Ahn Jung-Joon , You Lin , Kopanski Joseph J. 
Published: February 2020

The commercial introduction of three dimensional integrated circuits (3D-ICs) has been hindered by reliability challenges, such as stress related failures, resistivity changes, and unexplained early failures[i]. In this talk, we will discuss a new RF-based metrology, based on dielectric spectroscopy[ii], for detecting and characterizing electrically active defects in fully integrated 3D devices. These defects are traceable to the chemistry of the insolation dielectrics used in the through silicon via (TSV) construction. We will show that these defects may be responsible for some of the unexplained early reliability failures observed in TSV enabled 3D devices. While the immediate application has been in characterizing the reliability of prototypical 3D integrated circuits, the utility of this new technique could be extended to material characterization in general, for probing buried material interfaces in particular.
This low frequency RF technique could be optimized to compete favorably with other thin film metrology techniques, such as ellipsometry and FTIR, for mass production environments. Unlike the current state of the art spectroscopic methods, this new method does not need ‘line of sight’ of the analyte, and can be used to interrogate buried structures and interfaces.

[i](a) K.N. Tu, Microelectronics Reliability, 51( 3), 2011, Pages 517–523; (b) Papers in MRS Bulletin special issue on “Material Challenges in 3D IC Technology”, 40(3), 2015
[ii] F. Kremer, A. Schönhals “Broadband dielectric spectroscopy” Springer, Berlin, 2003.
Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy
Authors: Hung Mao-Chun , Chan Po-Fan , Dow Wei-Ping , Lee Hsiao-Yen , Lin Yi-Sheng , Yang Ping-Feng 
Published: February 2020

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load.
In this study, we adopt Ni-Fe alloy film as the shielding material and manufacture it by electroplating. We intend to explore the effects of plating solution composition, plating parameter and plating additives on structural strength and magnetic properties of the Ni-Fe alloy film. In electroplating, plating additives play important roles. The results suggest that various additives lead to different crystalline orientations, grain sizes, and surface roughness. A correlation between the plated structure and the magnetic properties is studied. Additionally, anti-corrosion is improved by doping a few boron in the film. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing Ni-Fe alloy with high permeability and good corrosion resistance.
Highly Adhesive Displacement Plated Cu Seed on Cowb Barrier for All-Wet TSV Fill Process
Authors: Ohta Kohei , Inoue Fumihiro , Shimizu Tomohiro , Shingubara Shoso 
Published: February 2020

Fabrication of TSV is one of key technology for 3D-ICs. For realizing conformal barrier layers against Cu diffusion with a low temperature process is important to achieve highly reliable TSVs. Electroless plated metals such as Co-alloy and Ni-alloy are considered to have a high potential as a barrier layer.
We succeeded in conformal electroless plating of CoWB on SiO2, using DMAB as a reducing agent after forming self-assembled monolayer (SAM) of silane coupling agent (APTES) on SiO2 [1-2], assisted with Pd nanoparticle catalyst. The adhesion strength of CoWB decreased with an increase in film thickness [1], which might be due to an increase in film intrinsic stress. Electroless Cu plated film using reducing agent on the CoWB layer showed a very poor adhesion property. In this study, we studied to form electroless Cu seed layer with a high adhesion strength by displacement reaction without reducing agent, and furthermore examined the barrier and seed formation into a high aspect ratio TSVs.
The electroless CoWB plating bath composed of cobalt sulfate and tungstic acid as a metal salt, citric acid as a complex agent, DMAB as a reduction agent. The Cu displacement plating bath composed of sulfuric acid and copper sulfate, and its pH was 3.5. The adhesion strength was evaluated by the stud-pull test. Table 1 shows the adhesion strengths of various films such as CoWB (70nm) only, displacement plated Cu on CoWB, electroless Cu plated with reducing agent (glyoxylic acid) on CoWB. The adhesion strength of the 70 nm CoWB film was 20MPa. That of displacement plated Cu/CoWB was 50 MPa. The adhesion strength of electroless plated Cu with reducing agent was very poor. We succeeded in obtaining a high adhesion strength by Cu displacement plating.
Figure 1 shows the displacement plated Cu seed layer on 80 nm electroless CoWB layer in TSV. The diameter is 3 μm and aspect ratio is 10. Displacement plated Cu film was formed almost uniformly from top to bottom of TSV. The sidewall and bottom coverages of Cu/CoWB bilayer in TSV was 70 to 80 % against that of the flat area. At the bottom of TSV, Cu(40nm)/CoWB(40nm) bilayer was formed succesfully without delamination.
We succeeded in the formation of highly adhesive electroless plated Cu seed layer on CoWB layer. Further study of complete fill of TSV with ECP Cu is in progress.
References
[1] F. Inoue, T. Shimizu, H. Miyake, R. Arima, T. Ito, H.Seki, Y. Shinozaki, T. Yamamoto, and S.Shingubara, Microelectronic Engineering, 106 (2013) 164–167.
[2] F.Inoue, T.Shimizu, T. Yokoyama, H. Miyake, K. Kondo, T. Saito, T. Hayashi, S. Tanaka, T. Terui and S. Shingubara, Electrochimica Acta, 56-17 ,6245-6250, (2011).

Figure 1
(Invited) Probing Oxygen Activities and Their Effects on Cation Migration in Li Rich Mn Rich Layered Oxides
Authors: Meng Shirley 
Published: February 2020

Combining first principles computation with STEM/EELS experimental observations, we demonstrated that in the Li-excess materials oxygen vacancies are present in surface regions and assist the TM ion migration through a novel mechanism: during first cycle charging, after most TM ions are fully oxidized, oxygen ions start to participate in the oxidation process (lose electron) and oxygen vacancies would form with a formation energy about 0.5–0.6 eV. Possibly due to the slow oxygen migration, oxygen vacancies mostly form near the material surfaces and sub-surfaces with 5–6 atomic layers. A significant fraction of the TM ions in these regions therefore are subjected to five (or even less) O-coordination due to the presence of either oxygen vacancies or the broken TM–O bonds on the particle surfaces. TM ions in those five (or less) coordinated defect polyhedral sites become much unstable and will spontaneously migrate to the fully-coordinated polyhedral sites nearby in the Li layer. On the other hand, although many of the Li ions are extracted upon charging, stable Li–Li dumbbells are formed leaving only certain sites in Li layers that are available for TM occupation. Combination of the above two reactions therefore causes the formation of a spinel-like phase from the material surface towards the bulk until reaching a region (2–3 nm beneath the surface after the first cycle) where oxygen vacancy concentrations are too low to assist the TM ion migration. It is reported that although it might be subjected to a further phase change, this TM-ion-migrated region is present for 50 cycles with its thickness mostly unchanged.
Based on these in-depth understanding, we will report a novel approach in optimizing the lithium excess manganese rich layered oxides whose first cycle columbic efficiency and long term cycling stability and voltage stability could be significantly improved.

Acknowledgement: This work is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. DOE under Contract No. DE-AC02-05CH11231, Subcontract No. 7056412, under the Batteries for Advanced Transportation Technologies (BATT) Program
Modeling of LiFePO4 Charging/Discharging Dynamics Based on the Many-Unit Concept: Validation Against Operando XRD Data
Authors: Delacourt Charles , Farkhondeh Mohammad , Pritzker Mark , Fowler Michael 
Published: February 2020

LiFePO4 (LFP) was proposed as a battery material over 15 years ago and has been implemented in commercial cells for about 10 years now. In spite of its maturity, LFP is still the subject of intensive research, particularly related to the phase-separating nature of the material. A number of interesting and unusual experimental features of the LFP system have been reported in the literature, including the zero-current potential hysteresis,1 rate-dependent lithiation/delithiation mechanism,2 cycle-path dependence3 and the memory effect.4 All of these observations were successfully predicted using a simple mesoscopic model that we recently published and that relies on a many-unit approach.5 In this presentation, we demonstrate an extended mesoscopic model for phase-change materials and its validation by simulating operando X-ray diffraction results recently reported in the literature.6,7 This validation step helps refine the physical representation of the electrode because it simultaneously accounts for phase dynamics as revealed by the XRD data and the electrochemical features of LFP. This work paves the way towards a mathematical model that unifies all the experimental observations reported for this material over the years.
References:
1. W. Dreyer, J. Jamnik, C. Guhlke, R. Huth, J. Moskon and M. Gaberscek, Nature Mater., 2010, 9, 448–453.
2. R. Malik, A. Abdellahi and G. Ceder, J. Electrochem. Soc., 2013, 160, A3179–A3197.
3. V. Srinivasan and J. Newman, Electrochem. Solid State Lett., 2006, 9, A110–A114.
4. T. Sasaki, Y. Ukyo and P. Novak, Nature Mater., 2013, 12, 569–575.
5. M. Farkhondeh, M. Pritzker, M. Fowler, M. Safari, and C. Delacourt, Phys. Chem. Chem. Phys., 2014, 16, 22555.
6. H. Liu, F. C. Strobridge, O. J. Borkiewicz, K. M. Wiaderek, K. W. Chapman, P. J. Chupas, C. P. Grey, Science, 2014, 344, 1480.
7. X. Zhang, M. van Hulzen, D. P. Singh, A. Brownrigg, J. P. Wright, N. H. van Dijk, and M. Wagemaker, NanoLett., 2014, 14, 2279.
Implementation of Porous Media Flow Model in Sodium Sulfur Battery Simulations
Authors: Mason Jerry Hunter , Celik Ismail Bektas 
Published: February 2020

Sodium sulfur batteries are comprises of liquid electrode materials suspended in porous media. The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the presence of porous media, capillary pressure and the resulting capillary action become important. Because of the exponential dependence of capillary pressure on wetting phase saturation, sharp concentration gradients are possible between the inert gas and the sulfur/sodium polysulfide liquid within the cathode. These gradients may result in areas of high electrical potential variation leading to increased reaction rates which in turn can cause overconsumption of sodium in the cathode during discharge, thus preventing sodium from penetrating the entire depth of the cathode. During charge, high reaction rates cause sulfur to accumulate on the electrolyte surface at a rate faster than the sodium-polysulfide can displace it producing an insulating effect. Both of these occurrences can lead to even higher potential variations, which can lead to decreased efficiency and even cause failures due to effects of overheating.
A porous media flow model is implemented into a three-dimensional, time dependent, multiphysics model for sodium sulfur batteries in order to study the aforementioned phenomena. Transport equations for charge, mass and heat transport are discretized using the finite volume method and then solved simultaneously in a time marching fashion. Properties required for solving the transport equations, including fluid density, heat capacity and ionic conductivity, are calculated and updated at each grid location as a function of time based on the volumetric content and phase of each species within each control volume. Electro-chemical boundary conditions range from prescribed voltage to external circuitry, including resistance, power consuming and power producing loads (for the purpose of charging). Mass transport is coupled with charge transport via Faraday’s law. Darcy’s law is used to model capillary action within the porous media between the wetting phase (liquid) and non-wetting phase (inert gas). The porous media model is coupled with the continuity equation and with a separate diffusion equation which is solved only within the liquid phase. The porous media model has been verified and validated by simplified analytical solutions and numerical results from similar models found in the literature. This validated model is being applied to sodium sulfur batteries currently. A comparison study will be performed to analyze the importance of porous media effects in multiphysics sodium sulfur battery modelling.
Mesoscale Modeling and Simulation of Composition, Manufacturing, and Microstructure Effects on Electrical Conduction in Thermal Battery Cathodes
Authors: Reinholz Emilee Lolita , Roberts Scott A. , Schunk P. Randall , Apblett Christopher A. 
Published: February 2020

Li/FeS2 thermal batteries provide a stable, robust, and reliable power source capable of long-term electrical energy storage without performance degradation. These systems rely on a eutectic salt that melts at elevated temperature, activating the cell. When the electrolyte melts, the cathode becomes a suspension, with cathode particles suspended in a liquid molten salt. This suspension experiences mechanical deformation, or “slumping.” This slump changes the mechanical compression of the cell, as well as the tortuosity and electronic and ionic conductivity of the cell as the mesostructure of the cathode is reordered in response to the external compressive stress. The combined effect of deformation, component composition, and manufacturing conditions on electrical conduction has not been studied, yet the cathode electrical properties are critically important to battery performance.
We present simulation results from a computer model validated with experiments to elucidate the effects of conduction in FeS2 cathode pellets when composition and manufacturing parameters are varied. Experimental validation was achieved through impedance spectroscopy measurements of pressed-powder cathode pellets. Pellets were manufactured in-house with variations in pellet density, FeS2 particle size distribution, and ratio of FeS2 to electrolyte content. Impedance measurements of solid-state pellets were taken at 25, 100, and 200°C before and after slumping. We observed that electrical conductivity increased with relative FeS2 content and decreased with the FeS2 particle size distribution, but that the density of the pellets did not demonstrate a clear effect. Slumped pellets exhibited greater electrical conductivity at all temperatures and pellet thickness decreased by 1.8% on average due to slumping.
Sandia’s novel conformal decomposition finite element method (CDFEM) was applied to surface-meshed geometric representations of cathode microstructures generated from microcomputed tomography (MicroCT) reconstructions. MicroCT was performed on all pellet types before and after slumping, with approximately 0.5 μm pixel size achieved for >0.1 mm3 volumes. A particle surface mesh was generated for each volume using FEI Avizo software and combined with the CDFEM background mesh. Results from the SIERRA/Aria finite element code will be presented, including the effects of anisotropy, mesh size, system volume, and manufacturing conditions on electrical conduction through cathode models, and compared with the experimental trends that were observed in the laboratory. The understanding of manufacturing effects on battery performance is not well developed, and this effort represents a step forward in correlated and predicting performance of cells based upon observed manufacturing trends.

Figure 1
Real Time Multi-Cell Multiple Chemistry Simulation of Reformulated Electrochemical Battery Models for EV and Grid Applications
Authors: Lee Seong Beom , Pathak Manan , Lawder Matthew T , Subramanian Venkat 
Published: February 2020

The porous electrode pseudo-two-dimensional (P2D) model which includes several meaningful internal variables (including potentials and concentrations in solid and liquid phase) provides good predictive capability for battery simulation1. We have performed an orthogonal collocation reformulation of the P2D model for lithium-ion batteries2,3 . The accuracy and short computation time of the reformulated model4are well suited for electric vehicle (EV) and grid application. The use of a electrochemical based model allows for the inclusion of additional physics based phenomena in the model such as temperature, stress, and capacity fade mechanisms.
EV and Grid application involve large battery modules. In order to perform the most accurate simulation and control of these systems the model must include multiple cells in series parallel combination. For large modules charge balancing becomes problematic. Not all the cells will be at the same state of charge and health. In addition, for grid applications, one might visualize a situation in which lithium-ion batteries with different chemistries being used simultaneously, sometimes even flow batteries in combination with lithium-ion batteries. Systems like these require a thorough multiple cell system model to understand all of these effects.
This talk will present progress in real-time simulation of physics based models for batteries in hybrid environments.

Acknowledgements

The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS).

References

1. M. Doyle, T. F. Fuller, and J. Newman, J. Electrochem. Soc., 140, 1526 (1993)

2. Venkat R. Subramanian, Vijayasekaran Boovaragavan, Venkatasailanathan Ramadesigan, and Mounika Arabandi, J. Electrochem. Soc.,
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(4) A260-A271
(2009)

3. Paul W. C. Northrop, Venkatasailanathan Ramadesigan, Sumitava De, and Venkat R. Subramanian, J. Electrochem. Soc., 158 (12) A1461-A1477 (2011)

4. Venkatasailanathan Ramadesigan, Kejia Chen, Nancy A. Burns, Vijayasekaran Boovaragavan, Richard D. Braatz, and Venkat R. Subramanian, J. Electrochem. Soc., 158 (9) A1048-A1054 (2011)