bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) The Impedance of Bioelectrochemical Interfaces
Authors: Rueda Manuela , Prieto Francisco , Alvarez-Malmagro Julia 
Published: February 2020

Biological relevant molecules are known to get adsorbed at the electrode/electrolyte interface and the study of their adsorption is interesting in relation to biosensors design and development of supra-molecular vectors for drugs delivery. On the other hand, the structure and electrical properties of biomembranes are frequently modeled by modifying electrode surfaces with lipidic films. The study of these lipidic film coated electrodes is also relevant in relation to drugs delivery vectors. Both cases of electrode interfaces are usually characterized by capacitance measurements as a function of potential with the implicit assumption of a serial RC model circuit for the metal/solution interface. However, the application of the electrochemical impedance spectroscopy (EIS) and the corresponding analysis of data as a function of the frequency and of the applied potential to the electrode can provide detailed information about the kinetics of adsorption1,2, biomembrane reorganization phenomena and electron transfers through the film3.
In this communication the application of EIS to bioelectrochemical interfaces is illustrated by studying examples of the two kinds of electrode interfaces. The adsorption of adenine, one of the DNA bases, on single crystal Au(111) electrode is presented as an example of a Gibbs adsorption electrode interface, in which the adsorbate is present in the metal and the electrolyte phases, while the study of modified electrodes with phospholipid films exemplifies the electrochemical behavior of organized biomembrane coating the metal with the polar heads of the lipidic chains directed towards the electrolyte solution part of the interface.
The experimental procedures In the case of the two kinds of interfaces have to be designed in order to avoid interference of surface reconstruction phenomena (in the case of the work with single crystal electrodes) or film reorganization phenomena (in the case of phospholipids modified electrodes).
The results about adenine adsorption as a function of the pH of the solution allow us to evaluate the kinetics of the adsorption and their correlation with results previously obtained by the authors using FT-IR-spectro-electrochemical methods1,2. The results about phospholipids film coated electrodes allows us to conclude about the stability of the film as a function of the electric field and to analyze the plausible electron transfer through them, when adding electroactive compounds to the solution phase.
[1].- M. Rueda, F. Prieto, A. Rodes, J.M. Delgado, Electrochim. Acta, 82 (2012) 534
[2].- J. Alvarez-Malmagro, F. Prieto, M. Rueda, A. Rodes, Electrochim. Acta, 140 (2014) 476
[3].- M. Rueda, F. Prieto, I. Navarro, R. Romero, J. Electroanal. Chem. 649 (2010) 42
EIS Study on Solid Electrolyte Deposition of Copper Film
Authors: Narui Yuka , Kojima Kenta , Iwabuchi Toru , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki , Yanagimoto Hiroshi , Hiraoka Motoki , Iisaka Hirofumi 
Published: February 2020

Copper plating is generally used for the fabrication of a printed circuit board of electronic device. The patterning is carried out by masking with insulator for the partial plating on the substrate. Solid electrolyte deposition (SED) method using solid electrolyte instead of liquid electrolyte is strong candidate for an alternative plating technique without masking because the copper is deposited only on the substrate contacted with solid electrolyte. Figure 1 shows the scheme of electrochemical cell for copper SED. The electrochemical cell is quite simple, namely, a thin solid electrolyte membrane is sandwiched by substrate and counter electrode. The substrate works as a cathode during copper deposition. Copper plate is used for the counter electrode because cupric ions are dissolved into the solid electrolyte membrane by the anodic reaction. Cation-exchange membrane is used for the solid electrolyte since the mass transfer of cupric ions is controlled by migration originating from the voltage between two electrodes. The solid electrolyte membrane is immersed in CuSO4solution to absorb cupric ion by ion-exchange for over 24 hours before the polarization. The copper is deposited on the substrate when the potentiostatic polarization is performed.
Advantages of SED comparing with common electro-deposition are written as follows.
・Electrochemical cell is very simple.
・Post-processing is simple because of no masking.
・It’s environment-friendly because of a small quantity of liquid．
・The deposition rate is very fast because driving force of mass transfer of cupric ions is migration and the concentration of cupric ions is maintained constantly in the solid electrolyte membrane.
The deposition rate is determined by three steps, which are anodic dissolution of copper counter electrode, the mass transfer of cupric ions in solid electrolyte membrane and the cathodic reaction on the substrate. Therefore, the measurements of 3D electrochemical impedance were carried out to discriminate above-mentioned three contributions to the deposition rate of copper by SED.
Reference:
1) K. Akamatsu, Y. Fukumoto, T. Taniyama, T. Tsuruoka, H. Yanagimoto, H. Nawafune, Langumuir, 27, 11761-11766 (2011).

Figure 1
Analysis of Warburg Impedance of Lithium-Ion Rechargeable Batteries By Wavelet Transformation
Authors: Gamano Yusuke , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

An electrochemical impedance spectroscopy (EIS) is useful method to investigate the electrode structures in the lithium-ion Rechargeable batteries (LIRBs) because time constants in the electrochemical impedance can be discriminated. The impedance spectrum is usually measured by using a Frequency Response Analyzer (FRA) whose principle is based on Fourier Transformation (FT). In the present paper, we calculated Warburg impedance from time series data of voltage and current of batteries by Wavelet Transformation (WT). WT is one of the calculation methods to transform data in time domain to those in frequency domain. We selected complex Morlet mother wavelet (CMMW) to determine impedance spectrum because CMMW is composed of complex sinusoidal wave and Gaussion window function1).
The voltage response after current step imposed to battery is calculated by the following equation.
V(t) = V0
’
+RT/(nF)ln((c
E
*-2i√t)/(nFA√(πD
E)))/(c
S(0,t)) (1)
In the equation (1), V0’
is voltage at steady-state, R is gas constant, T is room temperature, F is Faraday constant, cE* is Lithium-ion concentration in the electrolyte, i is current, t is time, A is electrode surface area, D
E is diffusion coefficient and c
S is Lithium-ion concentration in the active material. This equation was derived from the Fick’s second law of diffusion. The Warburg impedance was determined from time series data calculated by theoretical equation (1), indicating that the electrode reactions are under diffusion control. The procedure to determine electrochemical impedance by WT is described as follows. First, a current step signal of 0.372 [A] was applied to the system. Then, the voltage response was calculated by the equation (1) after current step at 100 s. The wavelet coefficients of current and voltage were obtained by WT. The complex impedance was calculated by cross-spectrum of the wavelet coefficients. Finally, we obtained the impedance spectrum. The impedance spectrum determined by above-mentioned procedure indicated a typical locus of Warburg impedance, which is straight line whose slope is 45 degree. This method was applied to determination of the impedance spectra of a commercial battery (UR18650A). The diffusion coefficient of lithium-ion was estimated by the impedance spectrum.
References:
[1] Y. Hoshi, N. Yakabe, K. Isobe, T. Saito, I. Shitanda, M. Itagaki, J. Power Sources, 315, 351-358 (2016).
Trials, Tribulations, and Some Success in Developing Modeling Tools for the Electrochemical Industry
Authors: Landau Uziel 
Published: February 2020

The fundamentals of computational modeling of current distribution in electrochemical cells have been known and practiced in academic settings since the early 50’s. However, unlike conventional chemical facilities, electrochemical cells were still being designed empirically in the 80’s and 90’s, and to significant extent, empiricism prevails in the electrochemical industry even today. The underlying reasons for this slow penetration of modeling applications are discussed.
The advent of personal computers in the early 80’s presented an opportunity to provide wide access to quantitative modeling throughout the electrochemical industry. The considerations that guided the design of the first commercial CAD software package of electrochemical cells, “Cell-Design”, and its commercialization strategy are presented, including the roles of industry and government in this endeavor. By the late 80’s and throughout the 90’s additional software packages, with different features and marketing strategies became available. The relatively recent introduction of an electrochemical module to Comsol, presented yet another stage in modeling capabilities of electrochemical cells that became accessible to the industry. The different features and marketing strategies of the different modeling packages are described.
A major barrier to wide-spread penetration of quantitative modeling within the electrochemical industry has been the lack of property data, particularly as related to many different plating solutions with proprietary additives. To overcome this limitation, that affects mostly the small plating companies with limited access to electroanalytical tools and expertise, the “L-Cell”, a device for fast determination of kinetics parameters, has been introduced. The capabilities, advantages, and limitations of this instrument, in comparison to other tools, ranging from automated and specialized devices to the aging and simplistic, but still widely used, “hull-Cell”, are discussed.
Challenges facing the electrochemical industry and opportunities that will enable it to meet future technological needs, including, but not limited to modeling capabilities, are critically discussed. Tasks that can be best carried out in academic institutions and others that are more effectively accomplished in industry and the interactions between the two, based on the author’s experience, are presented.
(Invited) Electrokinetic Separations to Increase the Percent Solids of the Effluent from a Phosphate Mine
Authors: Orazem Mark E. , Kong Rui , Huang Yuelong , Dizon Arthur , Moghaddam Saeed , Bloomquist David 
Published: February 2020

Phosphate mining operations create a waste product, consisting of a dilute clay/sand/phosphate suspension that, due to the properties of the suspended solids (primarily clay), requires 25 to 50 years to densify via hindered settling and self-weight consolidation. The objective of this research was to develop and apply an effective electrokinetic separation process to phosphatic clay suspensions, generated during the beneficiation of phosphate ore, a major component of fertilizer. The use of an electric field to separate the water from the solids is attractive because the inherent stability of the clay suspension is due, in part, to the surface charges residing on the platelets.
Previous work by others has demonstrated the feasibility of batch-wise electrokinetic separation of phosphatic clay suspensions, but the process is widely regarded as uneconomical. The present research is predicated on the assumption that an economically feasible separation requires a continuous, electrokinetic separation procedure.
Solid-liquid separation represents a significant problem for the phosphate mining industry The waste suspensions, initially containing 3-5 wt% solids, are pumped to large impoundment areas termed clay settling ponds. When incorporated, the addition of flocculating agents produce a rapid, but partial, separation, to approximately 10 wt% solids. A further increase in solids content proceeds very slowly. Hindered settling, followed by self-weight consolidation, requires as much as 25 years to reach a solids content of 40 wt%. This is an important target value, because its shear strength will then allow the addition of a surcharge (typically a sand cap) to increase the consolidation rate and magnitude.
Through a systematic development of prototypes, from batch to semi-continuous with emphasis on water clarification to semi-continuous with emphasis on solids extraction, our team has developed a fully continuous electrokinetic dewatering prototype. The system takes advantage of the charged nature of the suspended solids. When subjected to an applied electric field, the solids are attracted to the anode and clarified water is collected at the cathode. The process is capable of generating a 40 wt% clay cake and clarified water with turbidity levels below 1 NTU within hours rather than years. Optimization of the design was possible by developing a constitutive relationship between the final solids content, the applied electric field, and the residence time.
Successful implementation of a continuous electrokinetic separation process will reduce the vast amount of water consumed by industry. While the process was developed for phosphatic clay suspensions, it is anticipated that electrokinetic dewatering may be applicable to other mining operations such as those associated with the oil sand tar tailings in Canada.
This presentation will describe the current state of development, including energy and power requirements.
(Invited) Ceramic Membranes for Gas Separation and Electro-Synthesis: Effect of Surface and Interfaces
Authors: Chen Yu , Liu Meilin 
Published: February 2020

Electrochemical cells based on membranes represent a highly efficient and economically viable approach to gas (hydrogen and oxygen) separation and electrosynthesis. For example, a cermet membrane consisting of a ceramic proton conductor and a metal (e.g., nickel) could be used for recovery of high-purity hydrogen from synthetic gas mixtures during various industrial processes such as coal gasification and water gas-shift reaction. Similarly, a cell based on proton conductor can be used for hydrogen production and ammonia synthesis. In particular, yttrium/ytterbium doped barium zirconate-cerate (BZCYYb) exhibits the highest proton conductivity in the intermediate temperature range. Further, BZCYYb-based materials have high tolerance to sulfur poisoning and coking under typical conditions for hydrocarbon reformation. To date, however, there is little mechanistic understanding of the surface electrochemical reactions. A fundamental understanding of the charge and mass transport processes associated with surface reactions is vital to achieving rational design of a new generation of membranes for gas separation and electro-synthesis. In this presentation, we will highlight our recent progress in understanding the effects of surface and interfaces on gas separation processes, aiming at elucidating the mechanisms that control ionic transport and selectivity to desired product formation.
(Invited) Electrospun Nanofiber Composite Bipolar Membranes
Authors: Pintauro Peter N. , Wycisk Ryszard , Cunningham Marc , Shen Chunhui 
Published: February 2020

Bipolar membranes, typically a laminate of an anion-exchange and cation-exchange membrane, have the unique capability to split water at a potential as low as 0.8 V while conventional electrolysis requires at least 1.2 V. Such membranes are employed in a number of important industrial processes, including the production of mineral acids, the recovery of organic acids from fermentation processes, pH control, and ion-exchange resin regeneration. The use of bipolar membranes in electrodialysis separations eliminates unwanted salt efflux and disposal problems and offers significant savings in electrical energy consumption. Recently, bipolar membranes have also been examined for use in self-humidifying hydrogen/air fuel cells, where the recombination of electrochemically generated hydroxide ions and protons at the bipolar junction produces water that improves membrane hydration, with higher power output at reduced feed gas humidity conditions.
We report here for the first time on the design, fabrication, and testing of a new bipolar membrane that was made by polymer nanofiber electrospinning, where the anion-exchange polymer is quaternized poly(phenylene oxide) and the cation-exchange polymer is sulfonated poly(ether ether ketone). This new membrane has a 3-D nanofiber bipolar junction with a very high interfacial area, unlike the typical 2D planar junction. This extended junction morphology is important for two reasons: (1) it improves the attachment (adhesion) of the two ion-exchange layers so that ballooning/delamination is minimized or eliminated and (2) the increased bipolar junction surface area will lead to a better distribution of the water splitting reaction and lower membrane voltage drop for the same operating current density. The procedure for membrane fabrication will be described and the performance of electrospun films will be compared to bipolar membranes in the literature.
A Method for Effective Work Function Monitoring
Authors: Marinskiy Dmitriy , Loy Thye Chong , Edelman Piotr , Lagowski Jacek 
Published: February 2020

The effective work function (EWF) is a critical gate parameter dependent on metal, dielectric, and interaction between them. As such, it requires stringent control, both in R&D stage and in manufacturing of advanced MOSFET’s. In this work we present non-contact charge-based EWF monitoring that brings advantages of cost-effectiveness and fast data feedback. The method extends our micro corona-Kelvin testing of dielectrics and interfaces in scribe-line boxes to EWF suitable configuration with a thin metal layer on a top of a dielectric.
Two key elements are used in the present method: 1) corona charge deposition on metal surface and 2) surface voltage measurement by Kelvin force microscopy. In a dynamic version of the flatband voltage determination, the surface voltage decay after corona charging is measured under modulated light conditions enabling parameter free extraction of VFB. Results for n- and p-type metals show sensitivity of VFBto EWF and agreement with results at end of the line CV measurements.
The micro corona-Kelvin method allows quantification of two more work function sensitive parameters: the silicon surface barrier, Vsb, and the tunneling barrier related to the band offset at the metal / high-k dielectric interface. Results for n- and p-type metals correlate with the expected behavior. Measurement of the silicon surface barrier, Vsb, can be especially attractive since it can be done on a blanket wafer with a thin metal layer over the high-k dielectric, providing means for high resolution mapping.
The third EWF sensitive parameter is obtained from the analysis of the tunneling current across the dielectric under negative bias condition, i.e. tunneling of electrons from the metal gate through the dielectric. Measured shifts of the tunneling barrier were consistent with EWF.
a Study on Via Filling Performance in a High-Aspect-Ratio Though-Silicon Via with Various Conditions of Leveler
Authors: Jin SangHoon , Lee Woon-Young , Lee Dong-Ryul , Lee Yu-Jin , Lee SangYul , Lee Min-Hyung 
Published: February 2020

The void-free filling of high-aspect-ratio through silicon via (TSV) is one of the technical challenges for 3D integration. In order to fill the TSV without void, generally, copper was electroplated into an acid bath including organic additives of accelerator, suppressor and leveler. Especially, organic additives play important role on inhibiting the TSV internal void by interaction between them [1-4].
In this research, we investigate the effect of chemical properties of levelers in copper electroplating bath on TSV filling performance. As the result, it was determined that TSV filling performance was strongly affected by molecular weight (mol. wt.) and nitrogen weight percentage per a monomer (N wt. %) of leveler. Only the levelers having less than mol. wt. 10,000 and over 20 N wt. % can succeed to fill a TSV without void under high speed electroplating of 1.3ASD. This result proves that the leveler with low mol. wt and high N wt. percent can inhibit the faster electroplating at the upper edge of TSV effectively even at the high current density. We confirmed the progress of void-free TSV filling under the optimized leveler condition using cross sectional optical microscope (OM) images according to plating time as shown in Fig.1.

[1] H. Ling, H. Cao, Y Guo, H. Yu, M. Li and D. Mao, International Conference on Electronic Packaging Technology & High Density Packaging (2009) 860-862.
[2] K. Zou, H. Ling, Q. Li, H. Cao, X. Yu, M. Li and D. Mao, International Conference on Electronic Packaging Technology & High Density Packaging (2009) 103-106.
[3] L. Ma, H. Ling, M. Li, J. Sun, X. Yu and Y. Li, 14th International Conference on Electronic Packaging Technology (2013) 356-359
[4] R. Beica, C. Sharbono and Tom Ritzdorf, Electronic Components and Technology Conference (2008) 577-583
Fig.1. cross-sectional OM images of TSV electroplated under optimized leveler condition according to plating time: (a) 150 sec, (b) 300 sec (c) 600 sec (d) 700 sec

Figure 1
Effect of Degraded Additives on Under-Fill TSV
Authors: Ahmed Shafaat , Findeis Paul , Troung Connie Nga , Cheng Tien Jen , Grunow Stephan , Rothkranz Ronald , Oakley Jennifer , Graves-Abe Troy 
Published: February 2020

In the past few years the 3D IC integration (3DI) stacking has emerged as a potentially novel approach for extending computing performance without the high cost of CMOS scaling. The 3DI stacking technology is thought to be the essential technology of the next generation high-end semiconductors which will provides improved performance, and reduced form factor for applications such as logic-memory integration, image sensors, MEMS, and LED. The through silicon via (TSV) is one of the main components for 3DI stacking. Copper plating has been used for TSV metallization due to its low resistivity, low cost, excellent plating efficiency, easy to integrate, excellent reliability and a unique bottom up fill capability in presence of additives in the plating bath. One of the major challenges in the TSV metallization by plating is embedded voids and underfill TSV. Among the many parameters in TSV plating; bath composition especially suppressor to accelerator ratio (S/A) significantly affects TSV under-fill. It has been seen that the additives also degrades over the shelf life aging depends on their storage condition. Since the degradation of both suppressor and accelerator is not happening in the same rate, the S/A ratio vary and thus found to be caused TSV under-fill.
Fig. 1(a) shows a cross-section SEM image of a TSV plated with BKM bath additives for 1600s. In contrast, Fig. 1(b) and 1(c) shows cross-section SEM images those were plated with same amount of BKM accelerator but with 10% and 25% less suppressor than the BKM respectively. It can be seen that the growth of copper inside the TSV increased~ 33% (with 25% lower suppressor) than the POR without increase of Cu film thickness on side wall, Chamfers and field area. Similarly, for a given suppressor, the copper fill rate can also varied by varying the accelerator concentration. In this paper, we will describe how additives affect the TSV under-fill and correlate the TSV under-fill with degradation of additives during their shelf life aging.
Fig. 1(a) Cross-section SEM image of a TSV deposited with BKM plating additives of accelerator and suppressor and plating process for 1600s. Fig.1 (b) and (c) shows cross –section SEM images of a TSV those were plated with same amount of BKM accelerator but 10 and 25% less suppressor respectively than the BKM condition but exactly same plating process and time as Fig 1a

Figure 1