bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) In-Situ Stress Measurements during Cobalt Electrodeposition
Authors: Stafford Gery R. , Graciano Vinicius Primo , Bertocci Ugo 
Published: February 2020

Electrodeposited Co has attracted much attention over the past several decades owing in part to its interesting magnetic properties. These properties are largely dependent upon the structure and morphology of the electrodeposit, which can vary dramatically with overpotential, electrolyte pH, and the presence of strongly adsorbing anions. For example, solutions with a pH < 2.5 will generally result in a mixture of both face-centered cubic (fcc) and hexagonal close-packed (hcp) Co on Au, while more alkaline solutions yield nearly pure hcp Co. The evolution of residual stress during thin film growth also depends on deposit microstructure and growth conditions, making in situ cantilever curvature measurements a nice complement to traditional electrochemical measurements during electrodeposition.
We have measured the stress response as a function of overpotential in films measuring less than 25 nm in thickness, from 0.1 mol/L NaClO4 + 0.001 mol/L Co(ClO4)2 (pH = 4.8) and at Co current efficiencies ranging from 65% to 90%. XRD analysis indicates that under these deposition conditions the Co is face-centered cubic and maintains the (111) texture of the Au substrate, suggesting epitaxial but not pseudomorphic growth on the Au. Figure 1(a) shows the measured stress-thickness product over the deposition/stripping cycle for several deposition potentials. The corresponding steady-state stress associated with these curves varies from 0 to 450 MPa tensile, with much of the increase occurring in the potential range of -1.22 V to -1.24 V vs. SSE. However, over this potential range there is no change in grain size or growth rate, factors typically associated with tensile stress generation. Interestingly, the corresponding stripping voltammetry (Figure 1(b)) shows than an additional stripping wave appears in films deposited at potentials that correspond to the large increase in tensile stress. These additional stripping waves are typically associated with hydrogen in the film, suggesting that tensile stress can be attributed to the co-generation of hydrogen. Interstitial hydrogen is typically associated with compressive stress, or post-deposition tensile stress as the hydrogen is liberated from the film. This talk will examine additional sources of hydrogen-induced tensile stress, such as the presence of hydrogen stabilized vacancies, defects found to be quite stable in fcc Fe-group metals and alloys deposited under conditions of H+ discharge. As a counter argument, we will consider the possibility that co-generation of hydrogen may alter the energetics associated with nuclei coalescence, through modification of the Co surface energy or subsequent grain boundary energy, rather than through changes in grain size.

Figure 1
Gold-Core Transition Metal Oxide-Shell Nanoparticle Electrocatalysts for Enhanced Oxygen Evolution
Authors: Strickler Alaina Leigh , Escudero-Escribano María , Jaramillo Thomas F 
Published: February 2020

The oxygen evolution reaction (OER) is important for many renewable energy technologies, including electrolyzers, CO2 reduction, and metal-air batteries. Currently, the slow kinetics of this reaction limit efficiencies of many of these technologies, necessitating the development of high performance electrocatalysts. In recent reports, Au supports have been shown to enhance the OER catalytic activity of many 3d-transition metal thin films in alkaline conditions. Herein, we translate the beneficial impact of Au supports to high surface area core-shell nanoparticles, where a Au-core is surrounded by an OER-active transition metal oxide-shell (Au@MxOy where M=Ni, Co, Fe, and CoFe). This work presents the synthesis, characterization and electrochemical performance of Au@MxOy nanoparticles and demonstrates universal activity enhancement over Au-free oxide nanoparticles. Of all the materials tested, Au@CoFeOx particles demonstrate the highest activity and stability with an overpotential of 328 ± 3 mV over two hours at 10 mA cm-2. This illustrates that strategically coupling Au support and mixed metal-oxide effects in a core-shell nanoparticle morphology is a promising avenue to device-ready, high performance OER catalysts.
Capacity Fade Analysis and Direct, Efficient, and Real-Time Simulation of Physics-Based Battery Models for Stand-Alone PV-Battery Microgrids
Authors: Lee Seong Beom , Pathak Chintan , Ramadesigan Venkatasailanathan , Gao Wenzhong , Subramanian Venkat R. 
Published: February 2020

Accurate and economical sizing of stand-alone power system components, including batteries, has been an active area of microgrid research, but current control methods do not make them economically feasible.1 Typically, batteries are treated as a black box that does not account for their internal states in current microgrid simulation and control algorithms.2 This might lead to under-utilization and over-stacking of batteries. In contrast, detailed physics-based battery models, accounting for internal states, can save a significant amount of energy and cost, utilizing batteries with maximized life and usability.

We have previously shown the implementation of the optimization and benefits of using the MPPT controller algorithm and physics-based battery model along with other microgrid components.3 In this talk, we will discuss some simple examples for microgrids as well as consider the model of battery as a pack, i.e. a set of cells in series and parallel with slight inherent variation in SoC and SoH. The results of the proposed approach are compared with the conventional control strategies and improvements in performance and speed are reported.

Acknowledgements

This work was supported by the Clean Energy Institute located in University of Washington, Seattle and Washington Research Foundation. The battery modeling work has been supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U. S. Department of Energy through the Advanced Battery Material Research (BMR) Program (Battery500 Consortium).

References

1. B. Subudhi and R. Pradhan, Sustainable Energy, IEEE transactions on,
4 (1), 89-98 (2013).
2. D. A. Beck, J. M. Carothers, V. Subramanian, and J. Pfaendtner, AIChE Journal,
62 (5), 1402-1416 (2016).
3. S. B. Lee, C. Pathak, V. Ramadesigan, W. Gao, and V. R. Subramanian, Journal of The Electrochemical Society,
164 (11), E3026-E3034 (2017).
Hydrogen Isotope Separation By Using Alkaline Fuel Cell
Authors: Ogawa Ryota , Matsushima Hisayoshi , Ueda Mikito , Dawson Richard 
Published: February 2020

Introduction
The heavy hydrogen isotopes, deuterium (D) and tritium (T) are important materials in the field of nuclear energy. Particularly in recent years, development of new effective separation method is required for the water contaminated by the T. Every day the enormous volume is accumulating in Fukushima Daiichi Nuclear Power Plant. The water electrolysis, which is the industrially most general separation method, has disadvantage that consume energy is tremendous. To solve this point, we have investigated novel hydrogen isotope separation system named Combined Electrolysis Fuel Cell (CEFC) [1]. In this system, hydrogen and oxygen produced by electrolysis is used for power generation in fuel cell. From this, we can save energy and get further isotope effect by electrochemical reaction in fuel cell. Actually we reported that the D isotope was enriched in water phase by fuel cells with anion or cation conducting polymer [2, 3]. Here, we newly focused on another type of fuel cell, Alkaline Fuel Cell (AFC), and investigated the separation mechanism by several electrochemical methods.

Experimental
The anode was Ru catalyst supported by carbon and the cathode was Pt one. The electrolyte was 30 wt.% KOH solution. Pure H2­­ or D2 gas was supplied to anode and air was did to cathode. The reference electrode was Hg/HgO. Linear sweep amperometry was measured at the scan rate of 20 mA/sec until the cell voltage reached 0.4 V. Simultaneously electrochemical impedance spectroscopy (EIS) was carried out by frequency analyzer. The frequency range was from 0.1 Hz to 1 x 104 Hz. The experimental temperature was 50 ºC.
3．Results
Figure 1 shows the cell voltage-current curves of AFC. The same values of cell voltage at 0 A did not clearly demonstrate that the equilibrium potential of hydrogen oxidation reaction depended on the isotopes. The activation overvoltage, which can be detected as the voltage drop when the current was applied, was about 0.2 V for both gases. On the one hand, the cell voltage decreased linearly until the current reached 1400 mA when H2 gas was used. On the other hand, the voltage of D2 result was remarkably fallen at 1160 mA. The difference of the cell voltage was mainly attributed to the anode potential. This result suggested that the H2 gas transportation in the gas diffusion layer was faster than that of D2 probably. In the meeting, we report the separation factor of the D in a ddition to the EIS results.
[1] H. Matsushima, T. Nohira, T. Kitabata, Y. Ito, Energy. 30 (2005) 2413.
[2] S. Shibuya, H. Matsushima, M. Ueda, J. Electrochem. Soc.
163 (2016) F704
[3] R. Ogawa, H. Matsushima, M. Ueda, Electrochem. Commun.
70 (2016) 5.

Figure 1
Sodium Titanium Phosphate As Cation Insertion Electrode for Electrochemical Separation Systems
Authors: Bootwala Yousuf , Shanbhag Sneha , Whitacre Jay , Mauter Meagan 
Published: February 2020

Electrochemical separation technologies such as capacitive deionization (CDI) have evolved to be an energy-efficient desalination possible solution for treating brackish and low salinity waters.1 The achievable ion removal capacity in using capacitive carbon electrodes ranges between 0.1-0.2 mmol/g of carbon electrode.2 Further, the capacity retention of carbon electrodes is poor due to electrode ageing. In this work, we investigate the use of sodium titanium phosphate or NaTi2(PO4)3 , a Na-ion superconductor (NASICON) material as a sodium-ion selective cathode for electrochemically-driven aqueous separations. Additionally, we also discuss the importance of self-discharge or diffusive loss of sorbed ions during open circuit conditions specifically in comparing CDI system performance with that of insertion type electrodes such as NaTi2(PO4)3.
NaTi2(PO4)3, has until now only been evaluated in concentrated aqueous electrolytes and specifically for aqueous Na-ion batteries. It is however important in the context of water treatment and desalination, that we consider its performance in dilute electrolytes. NaTi2(PO4)3 shows reversible sodium-ion removal behavior over a range of sodium ion concentrations. Round trip coulombic efficiency values for these systems typically range between 40-70%, depending on the operating pH and dissolved oxygen levels in water. The causes of this efficiency loss are competing charge consumption by the hydrogen evolution reaction (HER) during the ion removal step and the chemical de-sodiation of the cathode by dissolved oxygen during ion retrieval step. 3, 4These efficiencies are improved through the use of an ion exchange resin and controlling the composition of the water near the electrode.
In addition, retained-ion loss characteristics of electrodes used for water treatment are important from the standpoint of being able to intermittently operate the electrochemical separation process. Our studies show that in even presence of dissolved oxygen, a common constituent in natural and industrial waters, the self-discharge properties of the titanium phosphate electrode are superior to porous carbon electrodes used in CDI systems. In the light of our findings, present a discussion on the utility of NaTi2(PO4)3as a insertion based electrode for sodium removal from aqueous streams.

References

1. M. A. Anderson, A. L. Cudero and J. Palma, Electrochimica Acta, 55, 3845 (2010).
2. S. Porada, R. Zhao, A. van der Wal, V. Presser and P. M. Biesheuvel, Progress in Materials Science, 58, 1388 (2013).
3. W. Wu, S. Shabhag, J. Chang, A. Rutt and J. F. Whitacre, Journal of The Electrochemical Society, 162, A803 (2015).
4. A. I. Mohamed, NaTi2(PO4)3 as an Aqueous Anode: Degradation Mechanisms and Mitigation Techniques, in Material Science and Engineering, p. 150, Carnegie Mellon University (2017).
Electro-Conversion of Renewables Originating from Waste Streams of the Pulping Process
Authors: Waldvogel Siegfried R. 
Published: February 2020

The electrochemical conversion of biomass which does not compete with nutrition purposes represents an attractive field of research. In particular, waste streams that usually only employed for incineration can be used to make value-added chemicals, this approach is of interest in terms of ecological and economic aspects. In the pulping process, the major biomass by-products are lignin, tall oil, and turpentine fraction. The presentation deals with the selective electrochemical conversion of lignin to vanillin and diacids from turpentine fraction. Besides the electrochemical process, also valid work-up protocols are outlined.
Mechanistic Insights into Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Biorenewable Oxygenates
Authors: Chadderdon Xiaotong , Chadderdon David J , Matthiesen John Edward , Tessonnier Jean-Philippe , Li Wenzhen 
Published: February 2020

Electrochemical reduction of biorenewable platform chemicals is an emerging route for sustainable biofuel and chemicals production [1-3]. However understanding gaps between reaction conditions, underlying mechanisms, and observed product selectivity have limited the rational design of effective, active, and stable electrochemical systems. In this presentation, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction are explored through a combination of voltammetry, bulk electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes and lead to different products: (i) electrocatalytic hydrogenation (ECH) for methyl furan (MF) and furfuryl alcohol (FA) production, and (ii) direct electroreduction for dimers production. The contributions of each mechanism to the observed product distribution is clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

References:

1. Xin, L. et al., ChemSusChem
2013, 6, 674–686.
2. Matthiesen, J. E. et al. ACS Sustainable Chem. Eng.
2016, 4, 7098–7109.
3. Suástegui, M.; Matthiesen, J. E.; et al. Angew. Chem. Int. Ed.
2016, 55, 2368–2373.
Surface Treatment Method and Its Metrology for Preventing Pattern Collapse
Authors: Bai Chuannan , Wang Jingjing , Shalyt Eugene 
Published: February 2020

As semiconductor industry continues to make patterns smaller and more sophisticated, stable patterns with high AR (aspect ratio) is required. Pattern collapse is often affected by the AR, rigidity of pattern material, and surface chemistry of the sidewalls. Historically, hot IPA treatment was used but it does not support latest generation devices. One of the novel effective pattern collapse prevention approaches is the surface treatment with an organic layer [1, 2]. The modified structure surface has lower surface tension and the capillary force is reduced. This treatment process is normally performed by a silane-coupling reaction using organic solvent, so that the hydrophilic surface (-Si-OH) is modified to hydrophobic (-Si-O-SiR3) after silylation reaction. Silyning agent has limited stability and decompose upon exposure to air, moisture or reactive surfaces. Thus, there is a need the tight process control. A variety of spectroscopic methods were studied in order to measure selectively the active silyning agent and breakdown byproducts. Presentation will summarize advantages and disadvantages of different approached, preferred process control strategy and test results for non-reagent, real time analyzer of STM chemistry. TOKYO OHKA KOGYO CO., LTD. (TOK) is highly acknowledged for providing test samples and technical discussions.
[1] D. Mori et al. Surface treatment agent and surface treatment method United States Patent Application 15/268,904
[2] E. Kesters et al. Wet clean challenges in 22nm ½ pitch and 16nm ½ pitch Proceedings of SPCC conference 2017

Figure 1
Post Cleaning for FEOL CMP with Silica and Ceria Slurries
Authors: Tseng Wei-Tsu , Jha Amarnath , Stoll Derek , Wu Changhong , McCormack Tim , Yang JI Chul 
Published: February 2020

For the manufacturing of Si-based semiconductors, CMP is utilized extensively to enable FEOL process integration such as STI, deep-trench, ILD, and poly-open. Silica slurries are usually adopted for bulk oxide polish while ceria slurries are more suited for the final “buff” polish where high selectivity to nitride is required. The ever stringent requirement for scratch reduction leads to the trend of using nano-sized abrasive particles in all types of CMP slurries. However, the stronger adhesion force between these nanoparticles and wafer surface necessitates the re-design and optimization of post-CMP processes to meet the low PR/FM defect requirement.
The selection of proper chemicals is often the first step towards post-CMP cleaning. However, design of cleaning sequence, exploitation of the tool hardware, and optimization of operating parameters are equally critical to achieve maximum cleaning efficiency. As shown in Fig. 1, for an oxide or poly-Si CMP process with an acidic silica-based slurry, a preferred post cleaning process should operate in alkaline environment (e.g., pH 8~10) in order to build in repulsive zeta potential for easy of particle removal from wafer surface.
In this case, the use of an acidic pCMP chemical would be unfavorable from zeta-potential point of view. Replacement of acidic chemical with just DIW (pH ~ 7) leads to significant reduction in PR/FM. In addition, optimization of the directionality, spin rpm, arm oscillation speed…etc, helps eliminate the wafer center-heavy signature and reduces the defect count further down.
For FEOL CMP with ceria-based slurry running on a 3-platen polisher with serial meg tank/brush cleaning module, one can design the pCMP process based on the unique “reactive” nature of ceria abrasives, and also fully exploit the available hardwares and their process parameters. In this example, the POR process adopts only DIW in the meg tank. The go-to process, however, replaces DIW with a diluted acidic oxidizer so as to neutralize the reactive ceria abrasives, making it much easier to dislodge the particles from oxide wafer surface.
The significant FM NADD reduction with the go-to pCMP process illustrates the efficiency of adding the meg clean step with diluted oxidizer. Further PR/FM reduction can be realized by optimizing the hardware and machine parameters such as those listed in Fig. 2, from on-platen buff clean all the way to the terminal step of Maragoni drying. Furthermore, for a new pCMP process to be considered production-ready, run order effects, repeatability, and CoO reduction need to be taken into account as well. In addition, post-clean surface analyses are carried out to ensure no potential reliability concern.
Reference:
W.-T. Tseng, J. Hagan, K. Mohan, R. Hull, J. MacDougall, R. Murphy, L. Tai, S. Molis, “Post Cleaning and Defect Reduction for Tungsten Chemical Mechanical Planarization” ICPT, 2015.

Figure 1
A Novel Cleaning Approach to Remove the Carbon Contaminant from Ru Surface of EUV Mask
Authors: Kim Min-Su , Song Hee-Jin , Kim Hyun-Tae , Park Jin-Goo 
Published: February 2020

The surfaces of extreme ultraviolet (EUV) mask and optics are very vulnerable to carbon contamination during EUV lithography process. The top surface of EUV mask is coated with Ru capping layer to protect the mask substrate. Carbon contamination occurs on Ru surface when the EUV light of 13.5 nm interacts with the surface. The carbon contamination on mask surface is known to lose its reflectivity and change the critical dimension (CD). Thus, the removal of carbon contaminant from mask surface is required to maintain the integrity of EUV lithography process. Conventional cleaning methods such as SPM and UV cleaning are widely used for the removal of organic contaminants but can cause surface damages on EUV mask such as surface oxidation and etching of absorber pattern.
In this study, a novel cleaning mechanism is proposed to remove carbon contaminant using a quaternary ammonium hydroxide solution and an organic solvent mixture solution. According to the SN2 (nucleophilic substitution) reaction, hydroxyl ions are ready to react with carbon atoms as nucleophiles. Also, polar aprotic solvents such as DMSO solvate cations to actively assist hydroxyl ion reactions. Therefore, a study on the removal of carbon contaminants was carried out using a mixture of quaternary ammonium hydroxide solution and polar aprotic solvent. There have been limited studies reported on organic solvent cleaning in a semiconductor process for removal of photoresist. However, physical cleaning such as megasonic and UV treatment were applied to the organic solvent cleaning process to improve organic removal. Few studies have also been carried out to remove the photoresist by applying an additional cleaning process such as CO2 aerosol, megasonic, and UV pretreatment to the organic solvent. So far no studies have been reported on the removal of carbon contaminants using quaternary ammonium hydroxide solution with an organic solvent. This study investigated the effect of cleaning solution on hydrocarbon film removal by using four kinds of quaternary ammonium hydroxide (TMAH, TEAH, TPAH and TBAH) as alkaline chemicals and DMSO and THF organic solvents as polar aprotic solvents. Instead of EUV carbon contaminant, a hydrocarbon film with similar properties to EUV carbon contaminant was prepared and evaluated using alkaline chemicals and organic solvents. The hydrocarbon film was effectively removed from Ru surface in the mixture of TBAH and THF. This is because of low polarity nature of both TBAH and THF. When DMSO used with quaternary ammonium hydroxide solution, hydrocarbon was also removed with longer process time. The carbon removal efficiency is improved and reduced the cleaning process time for TBAH+DMSO cleaning process with megasonic due to the easy lift-off of hydrocarbon film from Ru surface. The polarity of carbon contaminant and cleaning solution have to be considered for removal carbon contaminant from Ru surface.