bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Novel, Environmentally Compliant Magnesium Coating System for Corrosion Protection of Magnesium Alloys
Authors: Nunez Michael , Naccarelli Anthony , Sikora Elizabeth , Shaw Barbara A
Published: February 2020

Due to its low density and good mechanical properties, Mg and its alloys are very attractive materials for aerospace applications. However since Mg is the most electrochemically active structural metal, protecting it from environmental degradation presents a real challenge. Corrosion of Mg alloys depends on their chemical composition and microstructure. The intermetallic phases formed during production processes are more noble than the Mg matrix and result in the establishment of microgalvanic cells within the Mg alloy; thus, accelerating the overall corrosion of the Mg. To shield Mg and its alloys from corrosive environments, their surfaces are usually protected by chemical and conversion inorganic coatings, sol-gel coatings, anodization, or thermal spraying. But one has to be aware that defects present in the coating or developed during operation often result in the formation of galvanic cells leading to accelerated corrosion of Mg component.

An ideal, effective coating should be able to simultaneously provide corrosion protection through: sacrificial anode-based cathodic protection, active corrosion protection to minimize corrosion at defects (for example by releasing active inhibitors), and formation of a protective barrier layer on the substrate surface. Producing a protective coating which could fulfill the above requirements is extremely challenging. For example, creation of sacrificial coatings for Mg substrate is not an easy task, because there are not many engineering materials more active than Mg alloys. However physical vapor deposition technology can be employed to produce anodic coatings capable of sacrificially protecting Mg alloy components.

Our preliminary results show that physical vapor deposition process indeed can produce thin films of Mg alloys with sacrificial properties. These thin films were tested in artificial sea water in ambient conditions:

Alloy

Form

OCP (V vs. SCE)

Corrosion rate, mpy

Pure Mg
bulk
-1.6
131.3

Thin film
-1.9
27.6

AZ31
bulk
-1.6
34.3

Thin film
-1.8
3.6

AZ91
bulk
-1.6
9.5

Thin film
-1.8
6.3

The electrochemical parameters show that thin films not only exhibit lower corrosion potential (on average lower by 200 mV) but also have lower corrosion rate. Obviously, the corrosion performance of the thin film is a function of the microstructure of the deposits and this in turn depends on deposition parameters. The key factors in deposition process which enable production of films with tailored properties will be discussed.
The Effects of Oxygen Concentration and pH on the Galvanic Protection of Tin
Authors: Geary Steven , McMurray Hamilton Neil , de Vooys Arnoud C.A. , Wint Natalie
Published: February 2020

SVET is used to investigate rapid detinning processes affecting commercial tinplate (produced by TATA steel) in the malic acid solutions, commonly found in tinned food products. In malic acid concentrations ≥ 0.1 mol dm-3 tin was found to become sacrificial with respect to iron, reversing the polarity predictions on the basis of tabulated Eo values. The tin dissolution mechanism in aerated solutions is shown to be cathodically controlled by the mass transport of oxygen to the exposed steel cathode [1]. The sweeping removal of the tin coating is represented in Figure 1 which shows SVET-derived current density maps, the localised anodic dissolution of tin intensifies with an increasing cathodic steel surface area supporting the oxygen reduction reaction.

Particular emphasis is given to the effects in low partial pressures of oxygen replicating the conditions occurring inside a food can. A novel, Environmentally controlled Scanning Vibrating Electrode Technique (E-SVET) is described which allows the measurement of localised corrosion current flux under conditions of controlled oxygen partial pressure. Experiments undertaken using the E-SVET show that reducing the oxygen partial pressure significantly reduces the detinning rate due to the limited oxygen supply for the cathodic oxygen reduction reaction. Polarity reversal and oxygen reduction kinetics are confirmed using global electrochemical techniques such as RDE and OCP [2,3].

[1] S. Geary, H. N. McMurray and A. C. A. de Vooys. ECS Transactions, (2013), 50, p37-51.

[2] M. S. Abdel-Aal and M. H. Wahdan. British Corrosion Journal, (1988), 23, p25-28.

[3] V. Jovancicevic and J. O'M. Bockris. Journal of The Electrochemical Society, (1986), 133, p1797-1807.

Figure 1. 3D SVET-derived maps showing the distribution of normal current density J above a detinning 2.5gm-2 non-reflowed tinplate sample in 0.1 mol dm-3 malic acid at (a) 3 hours, (b) 3.9 hours and (c) 4.8 hours and (d) 5.1 hours of immersion.
Organometallic Deposition of Nickel: An Electroless Route to Nanoscale Films
Authors: Shviro Meital , Paszternak Andras , Zitoun David
Published: February 2020

We have demonstrated that designed reactive organometallic precursors could be decomposed to form metallic coatings on almost any substrate with unique control. This approach allows direct synthesis on any substrate, with the use of standard coating equipment such as spin coating. The synthetic pathway has been very successful with copper and nickel alloys and compounds, together with the discovery of enhanced electronic properties (magnetic moment, anisotropy, plasmon). These complex materials are now studied as catalyst layers in electrocatalysis of H2 oxidation and O2 reduction in fuel cells.

M. Shviro and D. Zitoun* Nanoscale

2012

, 4,
762-767

M. Shviro and D. Zitoun* RSC Adv.,
2013
, 3 (5), 1380 - 1387

M. Shviro, A. Paszternák, A. Chelly, D. Zitoun

*

J. Nano. Res.
2013
, 15, 1823
An Investigation of Electrodeposited Platinum Metal Monolayer Catalysts By X-Ray Photoelectron Spectroscopy and Cyclic Voltammetry
Authors: Vitale Adam , Alamgir Faisal M
Published: February 2020

Platinum group metals (PGM) are the catalyst of choice in a wide variety of catalytic reactions, including the oxygen reduction reaction. We present here our research on tailoring the near-surface electronic structure of core/shell catalytic systems under low-loading limits of PGM overlayers fabricated via surface-limited redox replacement. Synchrotron-based XPS allowed us to profile the transitions in the electronic structure from the surface down to the adlayer/support interface and beyond. Catalyst durability is also a significant aspect for further consideration, with catalyst instability oftentimes caused by metal dissolution or corrosion. It is has been shown that Au as a supporting metal can have a stabilizing effect on Pt even under high oxidizing conditions and thus can suppress Pt dissolution, resulting in improved durability of the Pt catalysts. This study looks at the durability of Pt monolayer catalysts by subjecting them to aggressive cyclic voltammetry cycling and by examining the activity of the surfaces towards the ORR during potential cycling in an oxygen environment. Samples with an overlayer thickness of 2 monolayers or less show a more dramatic decay in electrochemically active surface area under aggressive cycling, indicating poor durability. However, Pt surface retention is significantly improved once it is at least 3 ML, indicating increased durability due to chemical state and thickness of the surface. The cycling in oxygen-rich media show markedly enhanced currents for the ORR once a 2 monolayer Pt overlayer thickness is achieved, showing the highest activity towards the ORR relative to the amount of platinum present.
Electroless Deposition of Low-Cost Reusable Transition Metal Active Catalyst on Oxide Supports for Hydrogen Generation from Hydrides
Authors: Anderson Shannon , Deravil Latia , Rakap Murat , Kalu Egwu Eric , Onyeozili Edith N
Published: February 2020

Catalytic hydrolysis of alkaline NaBH4 solution and ammonia borane using electroless-based transition metal catalysts have been studied. The transition metal catalysts were synthesized by Pd catalyzation and activation of Al2O3 or TiO2 substrates and subsequent electroless plating of the transition metals. Results will be presented on the effect of Pd loading, annealing temperature of the catalyst, electroless plating time on the catalyst activity for hydrogen generations. Kinetic data of the hydrolysis reaction will also be discussed.
Investigation of CdS Thin Films Deposition by the SILAR Method Using Cd(II) Organic Salt as Precursor
Authors: Tamasauskaite-Tamasiunaite Loreta , Simkunaite-Stanyniene Birute , Zieliene Albina , Naruskevicius Leonas , Selskis Algirdas , Norkus Eugenijus
Published: February 2020

In the present study thin cadmium sulfide (CdS) films were prepared by means of the successive ionic layer adsorption and reaction (SILAR) method. Cadmium 2,4-pentanedionate and sodium sulfide precursors were used to prepare CdS thin films.

The morphology and composition of CdS thin films were characterized using Field-Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and X-ray Photoelectron Spectroscopy. The optical properties of CdS thin films deposited on the glass sheets were investigated by measuring optical absorbance in the wavelength range 300 to 800 nm.

The thin CdS films having a crystalline structure with CdS particles of ca. 20-80 nm in size were deposited on the glass sheet by the SILAR method. The data of optical properties of CdS films deposited with different thickness are compared and presented.

Acknowledgement

The work was carried out within the project VP1-3.1-ŠMM-08-K-01-009 that is partly supported by the National Programme “An improvement of the skills of researchers” launched by the Lithuanian Ministry of Education and Science.
Electrochemical Deposition of Mo-Se Thin Films
Authors: Kowalik Remigiusz , Kutyła Dawid , Mech Krzysztof , Zabinski Piotr , Wróbel Mirosław , Tokarski Tomasz
Published: February 2020

Semiconductors based on selenium are an important class of semiconducting systems which have been widely studied due to their electronic and optical properties. Among them the special attention is focused on molybdenum-selenium system now. The molybdenum chalcogenides are potential electrode materials for photovoltaic and photoelectrochemical applications due to their light absorbing properties in the visible region. Moreover this material has also been used as a catalyst for hydrogen evolution reaction instead of expensive platinum. Usually, thin films of these materials are prepared by high temperature and vacuum techniques. However electrodeposition has been found to be a very good and low-cost method to fabricate thin films of these compounds.

The electrodeposition of thin films of Mo-Se phases from aqueous baths were studied. The effect of different concentrations of selenious acid, sodium molybdate, pH and temperature were examined. Additionally different complexing agents embracing ammonia and citrate were tested. A conventional three-electrode cell: Pt-sheet as counter electrode and Saturated Calomel Electrode (SCE) or Ag/AgCl as reference electrodes were used. The different substrates were used as working electrode: gold, copper and ITO.

Electrodeposition mechanism and kinetics of Mo-Se system deposition were studied by the conventional electrochemical methods. Chronoamperometry and cyclic voltammetry techniques were combined with electrochemical quartz crystal microbalance to analyze this process in details. According to the obtained results the potentiostatic conditions were applied to deposit Mo-Se thin-films. The proper adjustment of the process of electrolysis has a crucial role on the composition and structure of the deposited films, which decide about their properties. The applied potential of electrolysis were changed systematically in ranges within which it significantly effects on the composition and structure of the Mo-Se thin films. The composition and the structure of the deposited thin films were identified by XRF, EDS, XRD and grazing incidence XRD techniques. Moreover the morphology of the samples were analyzed by SEM.

This work was supported by the Polish National Center of Science under grants 2011/01/D/ST5/05743, 2011/01/N/ST5/05509 and AGH University of Science and Technology contract no. 11.11.180.509.
Long Term Degradation of the Crystalline Silicon Solar Cells with Electroplated Cu Grids
Authors: Huang Qiang
Published: February 2020

One of the main cost in the silicon solar cell manufacturing is the silver paste for the screen-printed front-side grids. Furthermore, the aspect ratio and the conductivity the silver lines have been limited by the screen-printing process and the composite nature of the paste. The low aspect ratio and the low conductivity of the grids dictate a limitation of footprint of the grids and therefore a limitation of cell efficiency. In addition, the process of screen-printing involves high risk of wafer breakage, which further contributes the final cost of solar energy.

Electroplated Cu together with Ni silicide contact layer was proposed decades ago as an alternative for the front-side grid.[1] Light induced electroplating[2-4] was also invented to create minority carriers at the PN junction, allowing the electroplating to take place without reverse biasing the PN diode. While the a lot of efforts have been focused on the development of the manufacturing processes, few studies are available on the long term reliability of the Cu grid.[5]In this paper, the long-term thermal stability of the Cu/Ni metallization on was studied using Si solar cells fabricated with CMOS grade Si substrates.

Solar cells in real operation in the field will be challenged not only by heat, but also by moisture, radiation, and other natural stresses. While the reliability tests for Si solar cells with screen-printed Ag grid have been standardized already, the impacts of these stress elements are unknown to the Cu grids and are typically convoluted. However, the further formation of the silicide that could finally penetrate through the emitter and the diffusion of the Cu across the silicide into the Si are expected to be the major concerns for the Cu grids under thermal stress.

In this study, solar cells were annealed at different elevated temperatures to speed up the degradation. Degradation behaviors of the grids after up to 3 years were studied. Different materials were also evaluated and compared for improvement in the grid reliability. For example, figure 1 shows a comparison between the solar cells plated with pure Ni or NiCo alloy before the silicidation. The presence of Co in the silicide apparently improved the stability of the final grids during the stress tests at elevated temperature. Further detailed discussion will be provided in the talk.

REFERENCES

1 D. A. Yates, US Patent No. 4609565 (1986).

2 L. F. Durkee, US Patent No. 4144139 (1979).

3 L. A. Grenon, US Patent No. 4251327 (1981).

4 G. Hamm and D. L. Jacques, Patent No. 7955977 (2011).

5 J. Bartsch, A. Mondon, K. Bayer, C. Schetter, M. Hörteis, and S. Glunz, Journal of The Electrochemical Society 157(10), H942 (2010).

Fig. 1: IV characterization of Si solar cells after annealing at 300C for different time. The solar cells comprises (upper figure) Ni silicide and (bottom figure) NiCo-alloy silicide as the contact layer.
Electrochemical Synthesis of Composites Based on Polythiophenes and Carbon Materials for Use in Photovoltaic Systems
Authors: Hernández-Moreno Gibran , Gutiérrez-Granados Silvia , Frontana-Uribe Bernardo A. , Maldonado-Rivera José L.
Published: February 2020

Solar radiation is the renewable energy source with practically unlimited access. Scientific research has development devices capable of transforming this vast resource into electrical energy (solar cells). The organic solar cells (OSC) have emerged as a promising photovoltaic (PV) technology because of he possibility of low cost production and flexible devices. In a normal structured OSC device, the active layer of donor–acceptor blend is sandwiched between the indium tin oxide or ITO (anode) coated on the glass substrate and a low work function metal (cathode). The active layer of OPV is constituted by a mixture of a polymer electron-donating (conjugated polymer) and electron-acceptor compounds (usually fullerene derivatives). This material is blended in a bulk heterojunction architecture in order to enhance the performance device. Currently there are several ways to deposit the active layer (spary coting, thermal evaporation, spin coating), using mainly polymeric chains, aqueous systems and high weight molecules.

The use of electrochemical techniques for the development of conductive polymers, has primarily focused on understanding the mechanisms of polymerization, growth and redox behavior of these. The use of these methods has resulted in the development of polymer films with potential use in transistors, diodes and others.

The aim of this research is the development of photovoltaic devices using electrochemical techniques (cyclic voltammetry and constant potential) to generate the active layer of a conventional device. Performing in situ polymerization, incorporating of electroaceptor material in organic solvents.

The deposits of the active layer is made using a three electrode cell convecional, ITO working electrode, a platinum plate counter electrode, and Ag/AgNO3 reference electrode in acetonitrile, using bithiophene as electron donor molecules, oxidized multi-walled carbon nanotubes, oxidized graphene, ICBA and PCBM as acceptor molecules. Getting different morphologies and behaviors. Morphological analysis of the films were performed using an atomic force microscope (AFM). Determining the morphology and thickness of these layers.

The photovoltaic device was completed using Wood's metal as cathode, thus different devices were obtained.

Finally, the JV curves were obtained of the photovoltaic devices.
Electrodeposition from Ionic Liquids: Which Processes Have the Potential for Commercialization ?
Authors: Endres Frank
Published: February 2020

Electrodeposition from aqueous solutions is well developped and widely used in the electroplating industry. One example among many other ones is the deposition of zinc on steel, in order to slow down or even prevent atmospheric corrosion, e.g. of cars. Such deposition processes are limited by the electrochemical window of water, which does not allow the deposition of reactive elements like Al, Ta, Nb, Si, Ge and other ones. Ionic liquids, that have gained a lot of interest in the recent years, have electrochemical windows that in some cases are as wide as ± 3 V vs. NHE. Thus, they allow the electrodeposition of reactive elements. From AlCl3-based ionic liquids, often abbreviated as chloroaluminates, Aluminum can be deposited easily, and the main disadvantage might be that at least dry air is needed, as these liquids absorb moisture rapidly. Although low amounts of water are not a problem, continous absorption leads to a lower deposit quality, visible by black spots. Furthermore, the liquid has to be washed off carefully before the Al layers can be exposed to air. Neveretheless, such Al shows a good corrosion protection, for example of high and highest strength steels. Furthermore, nanostructured Al is of potential interest as host material for future Li ion batteries, and electrodeposition opens up an easy way to make macroporous materials for this purpose. A still rather rare possible application is the electrodeposition of semiconductors. Both Si and Ge can be electrodeposited as thin layers (and we have hints for GaN deposition), as nanowires/nanotubes and macroporous materials, and the deposits are amorphous. At the first glance this appears to be disadvantageous, however, at the second glance amorphous Si is of high interest as host material for Li ion batteries. Amorphous thin Ge is of considerable interest for ultrathin layers of future solar cells. The lecture intends to discuss that ionic liquids have their potential for future application in corrosion protection or in energy science, and maybe in other fields of electrochemistry.
Enhancing Fuel Cell Vehicle Lifetime: A Case Study on the Development and Use of a Corrosion-Resistant Electrocatalyst Support
Authors: Ramani Vijay K.
Published: February 2020

Longevity and reliability are essential for the successful translation of any new electrochemical technology to the marketplace. This paper addresses the issue of fuel cell stack durability in fuel cell vehicles (FCVs), which directly impacts both lifetime and reliability. The crux of the issue is electrolyte and electrocatalyst degradation during FCV operation, the former due to oxidative degradation in the presence of reactive oxygen species, and the latter arising from electrocatalyst and electrocatalyst support corrosion.

In collaboration with Nissan Technical Center North America, we have studied the issue of electrocatalyst support corrosion over the past several years. Carbon has traditionally been the support of choice as it is inexpensive, has high electron conductivity, and has adequate surface area. While carbon is thermodynamically unstable in the operating regime of a fuel cell, its corrosion rate is usually inhibited due to the intrinsically low exchange current density of the carbon electro-oxidation reaction. Unfortunately, during the start-up of a FCV, the fuel cell cathode undergoes potential transients that greatly enhance the overpotential for the carbon corrosion reaction (and greatly enhancing its rate) for short time-periods (milliseconds). Since the FCV will see many such transients during a lifetime of operation, an alternate strategy is required either in terms of inventing a new, corrosion-resistant support, or in terms of an engineering work-around to minimize the impact of the aforementioned potential transients. We have adopted the former approach (developing a new, corrosion-resistant electrocatalyst support material).

This presentation will outline non-proprietary aspects of the challenges encountered in executing this approach, including the need to (and difficulty associated with) truly understand(ing) the mechanism of degradation in an operating FCV, the efforts expended in correlating bench scale tests in the laboratory to post-mortem analyses of field-tested FCVs, the constraints in terms of cost and compatibility of materials, the need to develop truly representative accelerated stress tests that effectively mimic long-term degradation modes in a reasonable timeframe, and the timeline from lab-scale development of a viable alternative material to its implementation.
Keynote: From Science to Product: A Difficult Way
Authors: Rost Marcel J.
Published: February 2020

Working at the forefront of science, researchers are always interested in having a “toy” that allows unique experiments. In this way they surely can explore new ground and increase the probability for high-impact research and publications. In addition, funding becomes easier, as one has better chances in the competition with the other proposals.

Triggered by the advantage of a video-camera over a photo-camera, everything started 19 years ago with the scientific desire to observe film growth and surface dynamics with significantly higher time resolution. In the meantime we have realized full video-rate STM and we now can observe surface diffusion and phase transitions, live film growth during the deposition, live observation of ion erosion of surfaces, catalytic reactions on an atomic scale in a high-pressure cell at industrial conditions while also monitoring the reaction products, and we have realized a video-rate EC-STM with a bi-potentiostat and a flow cell that allows live observations during e.g. electrodeposition while we can change the potentials and/or (the composition of) the electrolyte. I will present typical examples of the capabilities of the different machines.

Our instruments are also commercially available via Leiden Probe Microcopy, of which I was the main founder in 2005. As I also was the CEO in the first 3.5 years (before I started my research group), I gathered firsthand experience on all crucial aspects that determine the success or the failure of a product that has to be brought from science to business. I will include both the different views of and the interplay between science, the researcher, the institute/university, the company, the market, financial aspects, and IP questions.

We surly have learned surprising lessons, which I will evaluate and, thereby, formulate several 'do's and don'ts of valorization'.
Ironic Chemicals
Authors: West Alan , Banta Scott
Published: February 2020

Most academic electrochemists and electrochemical engineers have rich and productive careers in research and take great pleasure in teaching. In the increasing statistics-obsessed world of academia, we monitor the impact of our research through publication metrics, while understanding that the interpretation of these measures is not straightforward. Another metric is seeing how our research impacts industrial application. In the high-tech, research intensive, example of copper electrodeposition for ULSI applications, we can observe industrial adaption of ideas for data analysis, paradigms for experimental programs, and through hiring of graduates. Nevertheless, many academic ideas will not be commercialized unless the original inventor or close associate is interested in the pathway from “invention to profit.”

There are multiple pathways that can be taken including direct University licensing of intellectual property and the creation of spin-out companies from the University. From an educational perspective, opportunities exist for students to learn about intellectual property, the unique economics of start-ups, and entrepreneurship. Frameworks to help academics start up companies have emerged, as evidenced, for example, in the NSF I-Corps program.1

We briefly discuss our experience with attempts at licensing intellectual property in the area of laser electroplating. We then discuss ongoing efforts to start up a company, which we have named “Ironic Chemicals.” The company employs a chemolithoautotrophic bacterium, which extracts its energy from the oxidation of ferrous ions to ferric ions. The ferric ions are electrochemically reduced, and the iron electrolyte is re-circulated between the bioreactor and the electrochemical reactor. The organism is genetically modified to produce chemicals or liquid fuels from dilute CO2, eliminating agricultural feedstocks.

We explain the technology behind Ironic Chemicals from both a scientific and business perspective, thereby illustrating how our instincts on speaking to potential investors were wrong. We discuss our experiences in customer discovery, as we attempt to convert an abstract business idea into a concrete understanding of what it will take to succeed. Furthermore, we share our experiences as we navigate questions such as, is the technology mature enough, how do we avoid conflicts of interest, and when should we talk with investors?

1. https://www.nsf.gov/news/special_reports/i-corps/
The First Thin Film Electronic Package: From Invention to Manufacturing
Authors: Krongelb Sol , Romankiw Lubomyr
Published: February 2020

As late as the end of the 1970’s, electroplating was regarded as a mystical shop art that had no place in microelectronic fabrication. In 1979 IBM introduced a magnetic thin film head made possible by a newly invented process that was based on electroplating – an achievement that cast electroplating in a new light. Today, electroplating has spread into applications ranging from nanoscale patterning of copper BEOL wiring below 10 nanometers on silicon chips to the deposition of materials for synthesis into photovoltaic layers on 60 cm by 120 cm solar panels, and has also made possible the use of metal structures in MEMS devices. The successful production of the thin film head with its precisely patterned high aspect ratio copper coils and its permalloy elements with tightly controlled magnetic properties, which plating experts of the 1970’s deemed impossible to do by plating, made device fabricators receptive to the electrochemical technology they once shunned.

An important new application of electroplating technology was in the fabrication of the multichip module. In advanced computers, these modules were multilayer ceramic structures that provided the power connections to the circuit chips and had a top layer of copper strip lines for data transmission between chips. The strip lines consisted of copper conductors with a rectangular cross-section that might be 6 µm high and 10 to 20 µm wide embedded in polyimide between two ground planes. These structures, which were essentially low-loss transmission lines, had to have precisely controlled propagation characteristics to minimize pulse distortion. Plating through a lithographic mask was an effective way of insuring the tight control on the geometry of the lines necessary to meet this requirement. One aspect of this talk will be to highlight the technical aspects of integrating electrochemical technology into the fabrication process for the transmission lines. The other will address how the scientists and engineers from the IBM T.J. Watson Research Center who had created the thin film head, worked with the development and manufacturing engineers at IBM’s East Fishkill plant to bring electrochemistry into their production line.

References:

S. Krongelb, J.O. Dukovic, M.L. Komsa, S. Mehdizadeh, L.T. Romankiw, P.C. Andricacos, A.T. Pfieffer, K. Wong, The Application of Electrodeposition to Advanced Package Fabrication, SPIE Vol. 1389, International Conference on Advances in Interconnection and Packaging, pp. 249-256 (1990).

S. Krongelb, L.T. Romankiw, J.A. Tornello, Electrochemical Process for Advanced Package Fabrication, IBM J. Res. Dev.
42 (5), pp. 575-585 (1998).

S. Krongelb, L.T. Romankiw, E.D. Perfecto, K.K.H. Wong, Electrochemical Processes in the Fabrication of Multichip Modules, Chapter 11, pp 337-372 in Microelectronic Packaging, edited by M. Datta, T.Osaka, J.W. Schultze, CRC Press, Boca Raton, FL (2005).
Acceleration of Electroless Silver Deposition from Solutions Containing Cobalt(II) as Reducing Agent
Authors: Jagminiene Aldona , Tamasauskaite-Tamasiunaite Loreta , Norkus Eugenijus
Published: February 2020

By using cobalt(II) complexes with ammonia or organic amines as reducing agents electroless silver plating solutions of high stability were developed; the deposition of high quality Ag layers with plating rate 1 – 3 μm/h are known [1-3].

In this work, the possibilities to increase silver plating rate without changing of concentration of reactants and temperature were studied. The additives enhancing the partial electrochemical reactions of the electroless plating process – anodic Co(II) oxidation and cathodic Ag(I) reduction – were applied. The effect of chloride and bromide ions was studied by electrochemical and chemical kinetics methods, including electrochemical quartz crystal microgravimetry (EQCM).

Electrochemical measurements showed that the Co(II) anodic oxidation on silver electrode is enhanced by the presence of halide ions. At 1 mM level, KCl additive change the rate of Co(II) oxidation only little, while KBr and KI increase the rate considerably. Accelerating effect of halides corresponds to the increase in adsorption ability of halides in the sequence Cl-<Br-<I-, the adsorbed halide ions could facilitate the electron transfer through the halide bridge. The electroless silver deposition was shown to increase by factor of 2-3 at chloride concentrations 20 – 50 mM at satisfactory solution stability. The enhancing effect is related to anodic cobalt(II) oxidation reaction. AFM images of the silver surface showed absence of considerable changes of real surface area, and the rate increase is obviously not caused by development of catalytic surface.

References

1. A. Vaškelis, E. Norkus, Electrochim. Acta 44 (1999) 3667.

A.Vaškelis, J. Jaciauskiene, A. Jagminiene, E. Norkus, Solid State Sci. 4 (2002) 1299.

E. Norkus, A. Vaškelis, A. Jagminiene, L. Tamašauskaite-Tamašiûnaite, J. Appl. Electrochem. 31 (2001) 1061.
Via Superfill with Time Pulse Plating in a Dual Couple Redox System
Authors: Nad Suddhasattwa , Sun Yang , Chalupa Radek , Pendyala Chandrashekhar , Ganesan Kousik
Published: February 2020

As fine line spacing (FLS) and blind micro vias (BMV) in substrate manufacturing progressively trend towards lower pitch, finer lines and high aspect ratios, electrodeposition of copper has become more challenging in the microelectronic packaging industry. Plating processes in substrate manufacturing necessitate high current densities to meet throughput concerns resulting in a high copper depletion gradient at the surface and via fill challenges to eliminate trapped voids. We present a manufacturable solution demonstrating a defect free, single bath electrolytic plating process by utilizing an “off-time” enabled forward-reverse pulses in a coupled Fe2+/ Fe3+redox plating solution.

DC plating, modulating plating by current density variation, has been the historical norm in plating techniques employed for via fill. Time pulse plating has the added advantage in its ability to tune composition, structure and porosity by employing varied combinations of current amplitudes and time pulses.

In a normal via-fill bottom up plating process, local plating rate is proportional to the local cupric ion concentration. The bottom of the via sees lower concentration than the top of the feature leading to pinch off or void formation. We investigated fluid velocity dependent convective transport inside the via. Flow velocities for both large and small vias were found to be very low for wide range of inlet flow velocities. Peclet numbers of < 10-4indicate an overwhelming dominance of diffusion impacting ion transport in the interior of the feature.

When an “off time” step is incorporated into a pulsed plating recipe, it enables the relaxation of the cupric ion gradient inside the via feature by diffusion (unhindered by consumption along the vertical sidewall) while the presence of the Fe2+/ Fe3+redox couple enables preferential etching of the top of the via feature versus the bottom. This exaggerates the bottom-up fill effect and can be tuned to achieve super fill of the vias leading to a robust void free filling.

We demonstrate that the incorporation of an “off-time” can result in void free fill and achieve super fill conditions in high aspect ratio via features.
Conditions at the Electrochemical Interface and Their Relation to Electrodeposition of High Moment Soft CoFe Alloys
Authors: Brankovic Stanko
Published: February 2020

Recent trends in magnetic recording and Micro-Electro-Mechanical System (MEMS) technologies favor electrodeposited Soft High Magnetic Moment (SHMM) alloys as the material of choice for fabrication of future magnetic devices [[1]-,[2],[3]]. The current efforts focus on synthesis of ultimately soft magnetic alloys with the maximum possible magnetic moment (2.4 T CoFe alloys), good corrosion resistance, high resistivity and low stress levels [3]. This seemingly difficult challenge is coupled with ever-continuing drive to miniaturize magnetic devices, bringing the electrodeposition to the level of nano-science [[4]-,[5][6]].

In this talk we will review our current understanding of the role of interfacial pH for obtaining good properties of magnetic alloys and nanostructures. The analytical model for Fe(OH)3 incorporation into deposit is presented with its relevance for control of CoFe alloy magnetic moment and coercivity. The analytical model is compared to experimental results illustrating incorporation of Fe-oxide species in CoFe alloys it is effect on magnetic moment and magnetic softness. Our attention is focused on presenting phenomenological relation between process parameters such as bulk pH, diffusion layer thickness, current efficiency etc.., and resulting oxygen content in CoFe alloys and their magnetic properties. The effective strategies for interfacial pH control, Fe3+ ion control and process design for manufacturing of CoFe nanostructures and thin films will be reviewed and their practical relevance for implementation in the real industrial conditions are discussed.

The authors acknowledge the support from NSF Chemistry division under the contract # 0955922.

[*] SRBrankovic@uh.edu

[†] The Electrochemical Society active member

REFERENCES:

[1]) E. I. Cooper, C. Bonhote, J. Heidmann, Y. Hsu, P. Kern, J. W. Lam, M. Ramasubramanian, N. Robertson, L. T. Romankiw and H. Xu, IBM J. Res. & Dev.,
49, 103 (2005).

[2]) W. Ehrfeld, Electrochim. Acta,
48, 2857 (2003).

[3]) S.R. Brankovic, N. Vasiljevic, N. Dimitrov, Chapter 27- Applications to Magnetic Recording and Microelectronic Technologies, Modern Electroplating V
, editors: M. Paunovic and M. Schlesinger, John Willey and Sons, Inc (2010), p 573,

[4]) X. M. Yang, H. Gentile, A. Eckert and S. R. Brankovic, J. Vac. Sci & Tech. B,
22, 3339 (2004).

[5]) X. M. Yang, A. Eckert, K. Mountfield, H. Gentile, C. Seiler, S. R. Brankovic and E. Johns, J. Vac. Sci & Tech. B,
21, 3017 (2003).

[6]) S. R. Brankovic , XM. Yang, T. J. Klemmer, and M. Seigler, IEEE Transactions on Magnetics, 42, 132 (2006).
High Speed Electrochemical Deposition Bath for Sn-Ag Alloy and Evaluation of Micro Solder Bump Plated on Ni-Coated Si Wafer
Authors: Kim Han Sik , Yi Sok Ho , Song Jung Hwan , Jeon Seong Sik , Kim Byeong Tak , Lim Ah Hyeon , Yook Jong Min
Published: February 2020

In flip chip packaging, especially high density interconnection, electrodeposition of Sn-Ag alloy has been attracted increasing attention from semiconductor industry as a replacement of toxic tin-lead solders. With aim of improving plating speed, life-time, and enhancing quality of micro solder bump, various electrochemical characteristics of strong acid electroplating bath composing of methane sulfonic acid (MSA), Ag-MSA, Sn-MSA, and several modification agents were investigated by using linear voltammetry techniques, cyclic voltammetric stripping (CVS) with controlled hydrodynamic condition with RDE. In addition, surface morphology, metallurgical structure and composition of Sn-Ag solder bump formed on Si wafer and deposition properties were characterized by using XRD, WDXRF, and SEM. The CVS measurements showed that suppressing the hydrogen evolution reaction at high cathodic current above 30mA/cm2 was critical, and small amount, less than 0.6 g/L, of benzylidene acetone was effective for this troublesome. The fundamental electrochemical responses revealed that the concentration of metallic complex ions, silver (I) and tin (II & IV), and its stability are crucial for better electroplating. In this study, the effects of complexing agent of thiourea, anti-oxidizer of hydroquinone, and several surfactants were also examined in terms of potential shift, current density, solution stability, and deposition rate. The results also showed that most electrochemical reactions in this bath composition are influenced by rotation speed, hence hydrodynamic conditions. With optimized bath solution, electroplating parameters, such as current efficiency, deposition rate, and elemental decay, and bath lifetime were also measured on micro-patterned Si wafer, and plating performance was compared with electrochemical properties. The optimized plating bath showed high deposition rate of 0.8μm/min/ASD, longer lifetime of 95 AH/L, proper eutectic alloy composition of 3.5 w/o and suitable for micro solder bump size of less than 20 μm. In this study, the relation of electrochemical and deposition characteristics with various additives and electrical properties of micro solder bumps will be discussed.
Magnetic Domain Control of Exchange Biased Magneto-Electric Thin Film Composites
Authors: Quandt Eckhard , Lage Enno , Urs Necdet , Röbisch Volker , Teliban Iulian , Knöchel Reinhard , Meyners Dirk , McCord Jeffrey
Published: February 2020

Magneto-electric composites constitute a promising class of materials for the application as highly sensitive magnetic field sensors. Their compatibility to miniaturization, their passive nature and their large dynamic range are just some of the numerous advantages of these composites compared to alternative magnetic field sensors, as e.g. flux-gates or magneto-resistive sensors. However, the highest sensitivities are observed in the presence of well-defined magnetic bias fields that are of significant disadvantage in terms of miniaturization and noise performance.

Self-biased magneto-electric composites, which are fabricated using the exchange bias effect [1], exhibit an increased total anisotropy in comparison to systems without exchange bias. As a consequence, small exchange bias fields are favourable because of a minor reduction of the magneto-electric voltage coefficient. However, weakly biased magneto-electric composites might loose their self-biasing properties and possibly show an increase of discontinuities in magnetization reversal due to the formation of magnetic domains. By a thickness variation of the ferromagnetic layer a maximum voltage coefficient αME ≈ 430 V/cmOe was found for a magnetostrictive multilayer of 3 x (5 nm Ta / 3 nm Cu / 8 nm Mn-Ir / 333 nm Fe-Co-Si-B). Yet, a stable single domain state indicating a well defined magnetization reversal by coherent magnetization rotation was achieved for layer thicknesses up to 100 nm Fe-Co-Si-B with a slightly reduced magneto-electric cofficient of αME ≈ 340 V/cmOe. This slight reduction is overcompensated by the improved control of the magnetic domain pattern that is highly desirable for magnetic field sensors and of special importance when frequency conversion techniques are applied [2].

[1] Lage, E., Kirchhof, C., Hrkac, V., Kienle, L., Jahns, R., Knöchel, R., Quandt, E. & Meyners, D. Exchange biasing of magnetoelec¬tric composites. Nature materials 11, 523–9 (2012).

[2] Jahns, R., Greve H., Woltermann, E., Quandt, E. & Knöchel, R. Sensitivity enhancement of mag¬netoelectric sensors through frequency-conversion. Sensors and Actuators A: Physical 183, 16-21 (2012).

This work was funded by the German Research Foundation (DFG) as part of the Collaborative Research Center 855 “Magnetoelectric Composites–Future Biomagnetic Interfaces”
Recent Progress on Electrodeposition of Magnetic Iron-Based Alloy Films and Nanowires
Authors: Schlorb Heike , Haehnel Veronika , Konczak Christoph , Pohl Diana , Funk Alexander , Oswald Steffan , Damm Christine , Schultz Ludwig
Published: February 2020

Magnetic iron alloys are of great interest for various applications such as magnetic storage, recording, sensing and actuating. The ongoing demand for further miniaturization, limited available resources and the wide variety of applications advance the search for specific preparation routes that allow tuning the material for each particular application. The most appropriate method is electrodeposition as it allows for the fabrication of complicated nanoscaled geometries, in particular high aspect ratio nanowires.

While binary alloys of the iron group elements are widely investigated, the deposition of more fancy alloys such as Fe-Pt, Fe-Pd or Fe-Ga represents a major challenge. Reasons for that are on the one hand large differences in the alloy constituent nobility that cause unstable electrolytes and on the other hand their strong tendency to hydrolyze and to form and incorporate undesired oxidic species into the deposit.

This paper summarizes our recent progress on the Fe-based alloys Fe70Pd30 and Fe80Ga20. Electrolyte requirements and deposition mechanisms are discussed. The selection of appropriate deposition techniques for the transition from thin film to nanowire fabrication is reported particularly taking into account changing transport conditions and thus, changed deposition kinetics in the restricted geometry of the nanoporous templates. The obtained structures, microstructures and magnetic properties are correlated with deposition parameters.

References:

[1] D. Iselt, K. Tschulik, S. Oswald, D. Pohl, L. Schultz, H. Schlörb, JES 159(7) H633 (2012)
Modification of Fe Alloys by Magnetic Field
Authors: Zabinski Piotr , Bialostocka Anna Maria
Published: February 2020

Electrodeposition is a very promising alternative to the physical vapor deposition techniques (PVD) to produce soft magnetic layers and microstructures. The advantage of electrodeposition in comparison to PVD processes is the fact that it is an inexpensive method.

Moreover, it allows depositing high aspect ratio layers with a thickness ranging from a few monolayers up to

more than 1 mm onto a complex geometry substrate.

The deposited layer properties could be tailored by a proper selection of the process parameters. A superposition of an external magnetic field during the electrodeposition has gained a considerable attention during the past decade, since it can affect the deposit properties. Mainly the morphology of the deposited layers is infuenced.

The electrodeposition process of Fe-Ni films was examined in a presence of homogenous magnetic field

(B: up to 0,6 T). Sulphate nickel and sulphate iron salt solution was used with pH 4,3.

The changes of surface morphology of Fe films electrodeposited without a magnetic field is observed.

The magnetic field superimposing perpendicular to the electric field leads to the hydrogen evolution promotion by MHD convection. This enhances the hydrogen evolution and the changes in Fe ions mass transfer appear near electrode surface. A change of local pH at the electrode is present and formation of different morphology of Fe layer.
Application of Photoelectro-Fenton/BDD Process Based on the Cathodic Production of H2O2 for Degradation of Industrial Dyes
Authors: Peralta Hernandez Juan Manuel , cruz-Rizo Alejandro
Published: February 2020

Photoelectro-Fenton/BDD process promotes in situ hydrogen peroxide (H2O2) by means of oxygen reduction via two electrons, adding Fe2+ to the solution resulting in the production of free hydroxyl radicals (•OH). The reaction can be catalyzed by the UV ligth accelerating the degradation of organic compounds in solution, because it promotes the photocehmical regeneration of Fe2+, and as a result a major •OH radicals production. In the present work, the authors discussed the study of the H2O2 production over boron doped diamond (BDD) cathode and the degradation of two industrial azo dyes, Blue-BR (B-BR) and Black-TRS (B-TRS) by photoelectro-Fenton/BDD (PEF/BDD) process using UV-ligth source. Comparative electrolyses carried out with 3L filter press pilot plant equipped with a BDD anode and cathode at constant current density showed the superiority of the processes with BDD because of the higher oxidation ability of ·OH formed from water oxidation at the BDD surface. Total mineralization was rapidly reached for the most potent treatment of PEF with BDD due to the additional oxidation by ·OH produced from Fenton's type reaction between added Fe2+ (0.5mM) and H2O2 generated at the cathode. Azo dyes decay always followed a pseudo-first-order kinetics. The influence of current density and substrate concentration on PEF with BDD was examined.
Electrochemical Oxidation of Methyl Parathion at a Boron-Doped Diamond Electrode
Authors: Campos-Gonzalez Eulalio , Vasquez-Medrano Ruben Cesar , Frontana-Uribe Bernardo A. , Ibanez Jorge G.
Published: February 2020

The commercial plaguicide methyl parathion (MP) is electrochemically degraded in a divided H-type cell equipped with two boron doped diamond electrodes, BDDE and a Nafion cation exchange membrane. High removals (i.e., >90%) of total organic carbon, TOC and of chemical oxygen demand, COD were obtained after 180 min at a current density, j of 5 mA/cm2 with a specific energy consumption, Esp
of ca. 200 kWh per kg of COD degraded. These results show that the anodic oxidation route may be an efficient alternative for MP degradation in polluted waters.