bluuebunny/crossref_metadata_2025 huggingface dataset:
Sodium-Ion Polymer Batteries Assembled with Composite Gel Polymer Electrolytes
Authors: Lee Yoon-Sung , G Kannan Aravindaraj , Shin Won-Kyung , Kim Dong-Won , Chung Kyung-Yoon
Published: February 2020

Rechargeable sodium-ion batteries have become the promising energy storage system due to their high energy density, long cycle life and lower cost. However, safety issues surrounding these batteries must be addressed before they can be widely utilized in large-scale applications such as electric vehicles and grid-scale energy storage devices. Therefore, the quest for safer and more reliable electrolyte system is urgent and polymer electrolytes are promising candidates in this regard. However, they suffer from poor thermal stability and mechanical properties. In order to obtain the gel polymer electrolytes with improved thermal and mechanical properties, ceramic fillers such as SiO2, Al2O3, TiO2 and BaTiO3 have been incorporated into host polymers. In these composite gel polymer electrolytes, the ceramic particles promote electrochemical properties of the polymer electrolytes through physical interactions without directly contributing to the lithium ion transport process. As reported in our previous studies, the ionic conductivity of gel polymer electrolyte was improved by using ceramic fillers covered with poly(styrene sulfonated lithium)(PLSS) containing lithium cation end group [1,2,3]. It is of our interest to synthesize and introduce inorganic materials containing dissociative sodium ions in the electrolyte of sodium-ion batteries to improve the ionic conductivity, thermal stability and mechanical property. In this study, we prepared composite gel polymer electrolytes based on core-shell structured SiO2 nanoparticles containing dissociative sodium ions. The SiO2 particles have unique core-shell morphology with a thin layer of poly(sodium 4-styrene sulfonate) surrounding nano-sized SiO2core particle. The composite gel polymer electrolyte exhibited high ionic conductivity and good mechanical strength. The prepared gel polymer electrolytes were used to assemble sodium-ion polymer batteries, and their cycling performances were evaluated.

References

[1] Y. -S. Lee, S. H. Ju, J. -H. Kim, S. S. Hwang, J. -M. Choi, Y. -K. Sun, H. Kim, B. Scrosati, D. -W.Kim, Electrochem. Commun., 17, 18-21 (2012).

[2] Y. -S. Lee, J. H. Lee, J. A. Choi, W. Y. Yoon, D. -W. Kim, Adv. Funct. Mater., 23, 1019-1027 (2013).

[3] Y. -S. Lee, W. -K. Shin, J. S. Kim, D.-W. Kim, RSC Adv., 5, 18359-18366 (2015).
Investigation of the Degradation of Metallic Lithium Electrode Protected By Bilayer Solid Electrolyte in Lithium-Oxygen Batteries
Authors: Le Hang T.T. , Ngo Duc Tung , Park Chan-Jin
Published: February 2020

To date, considerable efforts have been made to address the inherent problems of Li metal anode using solid electrolyte or modifying liquid electrolyte including additives, salts and/or solvents. However, despite their own advantage of good processability, the liquid electrolytes can induce the formation of the brittle and unstable enough SEI layer. Further, in order to preclude the Li metal from reacting with poisonous species such as water, O2, and CO2 diffusing from outside atmosphere, the use of lithium ion conducting solid electrolyte are indispensable.

 In this work, we report comprehensive investigation of degradation of protected Li electrode (PLE) in the presence of the bilayer solid electrolyte of LiPON/A-LLTO as a typical ceramic solid electrolyte in Li-O2 cell operating in both pure O2 gas and ambient air. The liquid electrolyte employed herein was 1 M LiTFSI in TEGDME. The evaluation includes analysis of structural and morphological change, analysis of surface chemistry change, monitoring electrochemical properties and subsequently exploring the difference in Li electrode’s degradation mechanisms in the cells with and without protection of the ceramic solid electrolyte. Furthermore, this present study supplies the circumstantial view of whole initiation and growth process of Li dendrites using optical microscope (OM). In particular, the formation process of dead Li dendrites that has barely exposed in the previous reports was also recorded.

 Obviously, with the presence of the solid electrolyte, the Li dendrites were effectively suppressed by the mechanical strength. The smooth and flat surface of the PLE was easily attained when the symmetric cell was cycled at low current density such as 0.1 mA cm-2. In addition, in the same charge-discharge condition, the symmetric cell without solid electrolyte only operated 15 cycles, much smaller compared with the cell with solid electrolyte, 182 cycles. During the cycling process, the impedance of both cells gradually increased  with cycling. However, the degradation of the cell without solid electrolyte was severer than that of the cell with solid electrolyte. XPS spectra confirmed the presence of decomposition products of LiTFSI salt such as LiF, Li3N, Li2S, Li2S2O4 and Sx on both tested Li electrodes after several ten cycles. However, these products of the PLE were detected with the smaller signal intensity than that of the unprotected Li electrode without the solid electrolyte. This suggests the effective suppression of electrolyte decomposition by the solid electrolyte. Hence, with the employment of LiPON/ALLTO, the Li dendrite growth and electrolyte decomposition were effectively suppressed. Accordingly, the Li-O2 cell using the protected Li metal electrode exhibited excellent charge-discharge cycling stability with a long life span of 128 cycles under the limited capacity mode of 1000 mAh g-1 in oxygen atmosphere and 20 cycles in air atmosphere.
Ultrathin Solid-State Li-Ion Electrolyte Membrane Facilitated By a Self-Healing Polymer Matrix
Authors: Whiteley Justin Michael , Taynton Philip , Zhang Wei , Lee Sehee
Published: February 2020

A new strategy is presented for forming thin solid membranes by creating an in situ derived self-healing polymer matrix penetrating the void space of an inorganic solid. The concept is applied as a separator in an all-solid-state battery with a FeS2-based cathode and achieves tremendous performance for over 200 cycles. Processing in the dry condition represents a paradigm shift for incorporating high active material mass loadings into mixed-matrix membranes.
Advanced Characterization of Li- and Beyond Li-Ion Battery Cathode Materials Via Electron Microscopy
Authors: Phillips Patrick J , Abraham Daniel P , Klie Robert F
Published: February 2020

The role of aberration-corrected scanning transmission electron microscopy (STEM) in materials characterization is examined with respect to layered-oxide cathode materials for battery applications. STEM-based methods are quickly becoming the most promising characterization tools for these materials, owed largely to the wide-range of techniques available on advanced STEM instruments, including the direct imaging of both heavy and light elements, and both energy-dispersive X-ray (EDX) and electron energy loss (EEL) spectroscopies. The current talk will focus on multiple materials, including Li- and beyond Li-ion oxides, characterized via STEM methods, in pristine, cycled, and in-situ irradiated states. The latter allows for single particle tracking of the dynamic processes occuring upon Li and O loss from the material. Various imaging modes, including high/low angle annular dark field (H/LAADF) and annular bright field (ABF), in conjunction with EELS/EDX, will be used extensively for this analysis, while parameters such as Mn valence, O presence, and light element occupation and intercalation will be discussed.
Microstructural Investigation of Pulse Electroplated Copper Trenches Deposited with Organic Additives
Authors: Marro James Brandon , Kapat Amrita , Darroudi Taghi , Okoro Chukwudi A. , Obeng Yaw S. , Richardson Kathleen A
Published: February 2020

Preferential grain orientation of copper (Cu) vias is speculated to result in a decrease in stresses in elastically anisotropic Cu.  On the other hand, highly twinned Cu microstructures are known to increase their electromigration resistance and mechanical properties, without significantly degrading electrical performance [1,2].  Therefore, the optimal manipulation of Cu via microstructure could enable the improvement of the reliability of microelectronic devices.  In this study, the “tuning” of the microstructure of Cu trenches were achieved by varying the bath’s chemical composition in different trench aspect ratios.  The organic additive system comprising of polyethylene glycol (PEG), bis-(sodium sulfopropyl)-disulfide (SPS), and janus green b (JGB) is commonly used in the electroplating of Cu into trenches and higher aspect ratio through-silicon vias (TSV) for microelectronics [3,4].  In this study, copper was pulse-electrochemically deposited (PED) into 500 nm deep trenches of various widths to evaluate the impact of aspect ratio on the evolution of copper microstructure.  Trench aspect ratios of 0.25, 1, 2, and 2.78 were investigated.  The organic additive concentrations in the PED bath were also adjusted to examine their influence on the Cu microstructure.  By metallurgical sample preparation and the focused ion beam (FIB) technique, the sample cross-sections of the Cu filled trenches were revealed for microstructural analysis using electron backscattering diffraction (EBSD).  From the EBSD data, the grain orientation and twin boundary distribution of the deposited Cu microstructure were analyzed.   

References:

1. L. Lu, X. Chen, X. Huang and K. Lu, Science,
323, 5914 (2009).

2. D. Xu, V. Sriram, V. Ozolins, J. Yang, K. N. Tu, G. R. Stafford, C. Beauchamp, I. Zienert, H. Geisler, P. Hofmann and E. Zschech, Microelectronic Engineering,
85, 10 (2008).

3. K. Kondo, T. Matsumoto and K. Watanabe, Journal of The Electrochemical Society,
151, 4 (2004).

4. M. Jung, Y. Song, T. Yim and J. Lee, Electronic Components and Technology Conference (ECTC), 2011 IEEE 61st, (2011).
Characterization and Metrology of Gold and Copper Electroplated Stylus Ion Traps
Authors: Arrington Christian L. , Hollowell Andrew E , Pillars Jamin Ryan , Singh Varshni , Finnegan Patrick , St. John Christopher R.
Published: February 2020

Electrochemical fabrication offers unique advantages for nano/microfabrication of 2D and 3D structures.  Precise control of deposition molds and thicknesses allows significant challenges to be solved through electrodeposition that are beyond the capabilities of standard silicon methods and conventional machining techniques. One unique application is the study of trapped ions enabling enhanced measurement techniques and reduction of anomalous motional heating 1. The main goal is to correlate the physical features with electric field noise, which can be sensitively measured with the ions. Previous two layer ion taps were created using electroformed gold into high aspect ratio molds, here we further investigate effects of chemistry make-up, applied current density, and pulse plating of gold and copper electrochemical deposition. The effects will then be characterized using scanning electron microscopy, profilometry, energy dispersive spectroscopy, x-ray diffraction, and electron backscatter diffraction to characterize feature height, feature dimensions, surface roughness, stoichiometry, crystal structure, and crystallite size. 

1              C. L. Arrington, K. S. McKay, E. D. Baca, J. J. Coleman, Y. Colombe, P. Finnegan, D. A. Hite, A. E. Hollowell, R. Jordens, J. D. Jost, D. Leibfried, A. M. Rowen, U. Warring, M. Weides, A. C. Wilson, D. J. Wineland, and D. P. Pappas, 'Micro-Fabricated Stylus Ion Trap', Review of Scientific Instruments, 84 (2013).

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2015-10657A
3D Printing and Electroless Metallization of Microrobots for Biomedical Applications
Authors: Bernasconi Roberto , Credi Caterina , Chatzipirpiridis George , Pané Salvador , Levi Marinella , Magagnin Luca
Published: February 2020

The manufacture of manipulators able to work wirelessly on a micrometric scale is one of the most interesting topics in microfabrication. Such devices, called microrobots, are expected to deeply change some aspects of modern surgery and to make in particular some medical treatments less invasive. Possible applications include localized drug delivery or confined modification of living tissues. Since motion in fluids at the microscale usually happens in low Reynolds number regime, the shape of microrobots is in general inspired by natural structures like bacterial flagella [1] or other propulsion apparatus of living cells well adapted to such conditions. For this reason shapes like rods, flagella [1] and helixes [2] have been tested in the existing literature. The most used method to control the motion of the devices is the application of a magnetic field [3], and due to this the microswimmers must have at least a part made of a metallic magnetic alloy.

Microrobots are nowadays realized using standard lithographic techniques, with high costs and poor flexibility of the production process. From this point of view the introduction of a manufacturing route based on additive manufacturing can introduce significant advantages. In the present work the possibility to directly 3D print the microrobots employing stereolithography (SLA) as technique is investigated. Typical designs like rods and helixes are employed. Since the SLA printing of metals is problematic, photocurable resins are used to produce the devices and the obtained samples are metallized via electroless plating to obtain the magnetic coating necessary for magnetic actuation. The quality of the 3D printed microrobots is evaluated, while the electroless process is first characterized from the general point of view and subsequently applied to the metallization of the devices. A first layer of a pure metal like copper is applied as flash layer, followed by a thicker layer of a suitable magnetic alloy. Finally the microdevices thus obtained are actuated in a controlled magnetic field and the motion at low Reynold number regime is studied.

[1] R. Mhanna et al.; Small 10, 1953 (2014)

[2] K. E. Peyer et al.; Chem. Eur. J. 19, 28 (2013)

[3] S. Kim et al.; Adv. Mater. 25, 5863 (2013)
Electroless Deposition of Platinum Using Multivalent Metal Ions As Reducing Agents
Authors: Norkus Eugenijus , Jagminiene Aldona , Stankeviciene Ina , Tamasauskaite-Tamasiunaite Loreta , Joi Aniruddha , Dordi Yezdi , Buzas Vytenis , Maciulis Laurynas , Tumonis Liudas
Published: February 2020

Two new type electroless plating processes for deposition of continuous platinum layer are proposed.

In the presence of different ligands Pt(IV) ions are reduced to the metallic state by means of multivalent metal ions.

In the first case Pt(IV) is reduced by Co(II) forming platinum and Co(III):

4Co(II)  +  Pt(IV) → Pt  + 4Co(III).

In the second type solutions Pt(IV) is reduced by Ti(III) forming platinum and Ti(IV):

4Ti(III)  +  Pt(IV) → Pt  + 4Ti(IV).

The kinetic data of the mentioned reactions are given and discussed.

Acknowledgement

This research was funded by a Grant (No. TEC-06/2015) from the Research Council of Lithuania.
Effect of Different Solvents on Aminosilane-Compound Modification and Its Influence on the Adhesion Between Electroless Nickel/Phosphorous Film and Silicon Wafer
Authors: Wang Wei-Yan , Hsu Chin Wei , Wei Tzu Chien
Published: February 2020

In semiconductor manufacturer and IC package, electroless deposition (ELD) of nickel/phosphorous (Ni/P) film is a special promising skill [1]. In general, the core of ELD is a catalytic reaction that needs a trace amount of noble metal such as palladium as the activator to lower the activation energy of metal formation [2]. Because the adhesion of ELD Ni/P film relates to the interfacial characteristic of catalyst and silicon surface. In order to enhance the bridging between the silicon substrate and palladium (Pd) catalyst, modifying silicon surface with organo-silane compound such as 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (ETAS) is commonly used. The ETAS treatment then forms a self-assembled monolayer (SAM) which is capable to interact with polymer-capped Pd catalyst and thereby promotes the adsorption of ELD Ni/P film [3]. However, it is known that the SAM formation is very sensitive to process condition such as soaking time and solvent agents.

In this study, various ETAS modification on silicon wafer are investigated. In particular, the ETAS-modified film was done by a wet-soaking method in which  the influence of soaking time and solvent agents onto silicon surface were discussed. As shown in Fig 1, the AFM images with various solvent agents of ETAS-modified surface showed significant difference which indicates that the solvent agents does influence SAM formation. The correlation on the solvent effect and the adhesion of ELD Ni/P on ETAS-modified silicon surface are discussed.

REFERENCES

[1] A. Brenner, G.E. Riddell, J. Res. Nat'l Bur. Std. 37 (1946) 31.

[2] L. Li, B. Liu, Mater. Chem. Phys. 128 (2011) 303.

[3] T. C. Wei, T. P. Pan, C. M. Chen, K. C. Lai, C. H. Wu, Electrochem. Commun. 54 (2015) 6

Figure 1
Temperature Effect on Silver Electrodeposition in a Deep Eutectic Solvent
Authors: Aldana-González Jorge , Botello Luis , Montes de Oca-Yemha Maria Guadalupe , Mostany Jorge , Romero-Romo Mario A. , Arce-Estrada Elsa , Palomar-Pardavé Manuel
Published: February 2020

This work was conducted to determine the influence of temperature of the electrolyte consisting of choline chloride and urea at 1: 2 molar ratio, for silver electrodeposition. Cyclic voltammetry and chronoamperometry analyses were employed to carry out the silver electrodeposition on glassy carbon at 50, 60 and 70 °C. The current density for silver electrodeposition increases with increasing temperature. The description of experimental data through Scharifker and Mostany model, see Figure 1 (a), indicate that the Ag nucleation and growth processes on glassy carbon, regardless of T, are a diffusion controlled processes. The diffusion coefficient, D0, the nucleation rate constant, A, the density of active sites, N0, the work of forming the critical nucleus, ΔG*, and the size of the critical radius, n*, are calculated from experimental data for all temperatures. From SEM images, the morphology of deposited Ag was seen to correspond to a progressive nucleation mechanism, regardless of T, and that the silver concentration in the electrolyte has a significant impact on the nucleation mechanism.

Figure 1
Electrochemical Removal of NOx on Pt-Ba Impregnated Lscf/GDC Electrode
Authors: Wang Xi , Shi Xiang Yi , Alexandre Westermann , Viricelle Jean-Paul , Rieu Mathilde , Vernoux Philippe
Published: February 2020

The NOx (mainly NO and NO2) pollutions that come from the exhaust of the thermal engines can give rise to a serious threat to the environment and human health. The design of more efficient and stable catalysts to reduce NOx to nitrogen in atmospheres containing excess oxygen (typically, from exhaust gas emitted by diesel and lean-burn gasoline engines) has attracted so much attention in the last years. The two actual technologies are using an additional reducing agent to remove NOx, i.e. Diesel fuel post-injection for the NOx storage reduction process and urea for the selective catalytic reduction. An alternative solution could be the electrochemical reduction of NOx in solid oxide electrolysis cell (SOEC)[1,2]that can save the huge reducing agents storage system.

This study reports the electrochemical properties for NOx reduction of a Mixed Ionic Electronic Conducting (MIEC) porous electrode promoted by Pt nanoparticles, as efficient catalyst for oxidation reactions, and BaO, as sorbents to store NOx. Pt and BaO nanoparticles were finely dispersed in the porosity of a MIEC film, based on a composite between LSCF (La0.6Sr0.4Co0.8Fe0.2O3-δ) and GDC (Gd0.2Ce0.8O1.9), which was deposited using screen-printing. This catalytic layer was interfaced on a dense pellet of gadolinium doped ceria (GDC), an O2- ionic conductor. The Ba and Pt loadings were around and 150 and 5 µg/cm², respectively. The catalytic performances, upon positive and negative polarizations, have been measured as a function of temperature in the range 200°C-500°C, partial pressure of oxygen and in the presence of propene in the feed. The NOx electrochemical conversion into N2 was found to be driven by the current (Figure 1) and the catalytic activity of the electrode for NO oxidation. In parallel, electrochemical properties have been carried out by using cyclic voltammetry and electrochemical impedance spectroscopy to investigate the electrocatalytic mechanism. Finally, the Pt and BaO nanoparticles in the LSCF/GDC film were characterized by transmission electronic microscopy.

References

T.J. Huang, C.Y. Wu, S.H. Hsu, C.C. Wu, Energy Environ.
Sci., 4, 4061 (2011).

R. M. L. Werchmeister, J. J. Bentzen, K. B. Andersen, and K. Kammer Hansen, J. Electrochem. Soc., 161(10) H663-H669 (2014)

Figure 1
Role of Elastic Strain on Electrocatalysis of Hydrogen Evolution Reaction
Authors: Yan Kai , Khorshidi Alireza , Guduru Pradeep R. , Peterson Andrew A.
Published: February 2020

We present a study on the effect of externally applied elastic strain on the catalytic activity of metal films in the context of hydrogen evolution reaction (HER). Thin metal films supported on elastic substrates are uniaxially strained in situ in compression and tension while they participate in the HER and their catalytic activity is measured through shifts in the cyclic voltammograms. We show that elastic strain tunes the catalytic activity in a controlled and predictable way; for each metal considered here, compressive and tensile strains have the opposite effect on the catalytic activity; also, the changes in the catalytic activity scale with the strain magnitude within the range of strain values accessed in our experiments. The experimental results show that Pt and Ni films show increased HER under compressive strain; while Cu's HER activity is retarded by compressive strain. The opposite was observed under tensile strain. The experimental observations are understood by considering the influence of elastic strain on hydrogen binding energy, which has been calculated through density functional theory (DFT). Compressive strain increases the hydrogen binding on Ni, shifting it towards the volcano peak, while tensile strain has the opposite effect. However, the same strains have the opposite effect on Cu since it is located on the other side of the volcano peak. By isolating elastic strain from the ligand effect, this study provides a better understanding of the processes that control electrocatalytic activity towards HER and can guide design of strained core-shell nano-particle catalysts.
(Science for Solving Society’s Problems Challenge Grant Winner) In-Situ Electrochemical Generation of the Fenton Reagent for the Treatment of Human Wastewater
Authors: Godinez Mora-Tovar Luis Arturo , Rodriguez Valadez Francisco Javier , Garcia Orlando , Fernandez Dennys , Zarate Ana I.
Published: February 2020

It is well known that water contaminated with human waste is an important problem in a large part of the world; particularly in developing countries where substantial investments must be made in physical infrastructure so that water treatment plants could be used. In this regard, a feasible approach to face this problem is the development of on-site technologies using affordable and small devices that could be installed in every household. The aim of this project was therefore to design, build, and characterize a small Electro-Fenton reactor for human wastewater treatment.

The approach that was employed is based on the cathodic generation of H2O2 from oxygen reduction in activated carbon (AC) packed electrodes along with the combination of this species with H+ and Fe2+ ions provided by a cation exchange resin. In this way, a three-chamber reactor was built coupling an AC packed electrochemical system (middle compartment) with two additional compartments that contained a cation exchange resin that will change between source and collecting cation functions in cycles with a frequency 1/t1. In this way, setting the flow rate in any given direction, one resin chamber provided protons and ionic iron as water flows trough it, taking these chemical species to the middle compartment where the Electro-Fenton process takes place. The second resin chamber collected the cations as they come out from the middle compartment and after t1, when the resin-loaded chamber was loaded, the direction of the water flow and the potential in the electrode compartment was switched so that the process started over again.

From measurements of iron and proton desorption and adsorption along with electro-Fenton experiments, it was possible not only to obtain cycling-working conditions for the reactor under study but also to observe the successful coupling between the adsorption an cathode functions of the polarized AC packed in the central chamber of the reactor. Furthermore, using this small prototype to treat water contaminated with Helminth eggs (HE) of Ascaris lumbricoides (a human parasite that is highly resistant to the disinfection processes due to its robust external layers) it was possible to observe that the performance of the reported approach is promising since preliminary results showed a more efficient disinfection than that obtained using electrochemically generated hypochlorite.

Figure 1
Simulation Study of Electrolyte Flow and Slime Particle Transport in a Newly Designed Copper Electrorefining Cell
Authors: Zeng Weizhi , Free Michael L , Wang Shijie
Published: February 2020

A model based in COMSOL Multiphysics (a finite element analysis software) consisting of a specially designed electrorefining cell was developed to simulate copper electrorefining. This cell has its inlet on the side wall near the cell top and its outlet on the opposite side wall near the cell bottom. The electrolyte enters from the inlet, flows directly into the gap between electrodes, and exits the cell from the bottom outlet. Unlike the flow field in conventional electrorefining cells that have inlets near the cell bottom and outlets near the cell top, the natural convection between electrodes in this cell can be suppressed by the inlet flow, which leads to concurrent downward flows along both the anode and the cathode. Copper concentration profile and fluid density profile were acquired as electrochemical simulation results. Electrolyte flow velocity field, slime particle trajectory, and slime particle distribution were obtained as fluid flow and particle transport simulation results. Features of the copper concentration profile, the electrolyte flow field, and the slime particle transport are discussed. The simulation results of this cell were compared with those of a conventional cell, and some advantages of this cell can be found: copper ions in the cell are more uniformly distributed between electrodes by the strong forced convection; electrode reactions can reach steady state at higher current densities and lower electrolyte copper concentrations; slime particles are more likely to settle to the cell bottom without affecting the cathode purity.
Memcapacitive Characteristics of Metal-Oxide-Semiconductor Capacitor Structures by Compositional Redistribution
Authors: Yang Paul , Noh Young Jun , Baek Yoon-Jae , Zheng Hong , Kang Chi Jung , Yoon Tae-Sik
Published: February 2020

Memcapacitive characteristics defined to be a memorized capacitance change has been recently suggested and experimentally demonstrated. Di Ventra et al. noted that the memcapacitive characteristics involve the capacitance change in metal-oxide resulting from microscopic geometry change or history-dependent permittivity change [1]. Wang et al. reported the memcapacitive characteristics in ionic transport through SiO2 conical nanopore in KCl solution caused by redistribution of mobile ions [2]. We previously reported the analog memcapacitive characteristics in pn junction diode structures [3]. The pn heterojunction with the assembly of n-type Fe2O3 nanoparticles having Pt core (called Pt-Fe2O3 core-shell nanoparticles) on p+-Si substrate exhibited gradually changing capacitance as repeating the application of voltage with respect to the polarity of voltage. The analog memcapacitive characteristics also emulated the biological synaptic potentiation and depression motions, which is indicative of potential application to neuromorphic devices as well as analog nonvolatile memory and circuits. Since the memcapacitive phenomenon exhibits the memorized capacitance change, the memcapacitor has a potential to modulate the forward and reverse current in diode structure through altering the barrier height and depletion width at the interface.

Also, the memcapacitance can modulate the drain current in MOSFETs and TFTs as variable gate stack capacitor, named memcapacitor, which gives the functions of memory, logic, neuromorphic operation, and so on. In this presentation, we discuss the memcapacitive characteristics in metal-oxide-semiconductor (MOS) capacitor structure consisting of reactive electrode (Mo, Al) and hafnium oxide (HfOX) on n-type Si and indium-gallium-zinc-oxide (IGZO) semiconductor substrates. The capacitance-voltage curves exhibited sequentially changing capacitance as repeating the voltage sweeps. The saturation capacitance was decreased as repeating +V application, while the depletion capacitance was barely changed as –V application. Also, the capacitance-time curves disclosed the same tendency of capacitance change. On the other hand, the MOS structure with inert electrode (Pt) did not show the capacitance change. These memcapacitive behaviors were induced by the migration of oxygen ions between reactive electrodes (Mo, Al) and HfOX, which modulated the permittivity and effective capacitor area. These results demonstrated the memcapacitive characteristics in MOS structure through voltage-driven oxygen migration for the application to memory, logic, and neuromorphic devices.

[1] M. Di Ventra, Y. V. Pershin, and L. O. Chua, Proc. IEEE 97 1717 (2009).

[2] D. Wang, M. Kvetny, J. Liu, W. Brown, Y. Li, and G. Wang, J. Am. Chem. Soc. 134,  3651 (2012).

[3] Y. J. Noh, Y.-J. Baek, Q. Hu, C. J. Kang, Y. J. Choi, H. H. Lee, and T.-S. Yoon, IEEE Trans. Nanotechnol. 14, 798 (2015)
Influence of Doping and Tunneling Interface Stoichiometry on n+In0.5Ga0.5As/p+GaAs0.5Sb0.5 Esaki Diode Behavior
Authors: El Kazzi Salim , Alireza A , Bordallo Caio Cesar Mendes , Smets Quentin , Desplanque Ludovic , Wallart Xavier , Richard Olivier , Douhard Bastien , Verhulst Anne , Collaert Nadine , Merckling Clement , Heyns Marc , Thean Aaron
Published: February 2020

Due to energy-filtering by band-to-band quantum mechanical carrier tunneling, Tunnel FETs promise the possibility of steeper subthreshold swings (SS < 60 mV/dec) than MOSFETs. Even if the ideal material combination is still unclear, simulations show that for a confined channel (width<10nm), the broken gap InAs-GaSb system is the most promising to have the lowest SS with the highest Ion at low supply voltages. On the other hand, it is demonstrated that Esaki diodes can be used to accurately measure Band to Band Tunneling (BTBT) for TFET performance prediction. Since the tunnel junction is key for the operation of both TFET and Esaki diodes operation, the effect of different kind of defects (dislocations, etc...) can be seen directly from the TAT current in the diode I-V trace. In this vein, we study in our work the Molecular Beam Epitaxy (MBE) growth and fabrication of n+InAs-p+GaSb Esaki diodes on three types of substrates: GaSb, GaAs and Si.

We first present the pseudomorphic growth of n+InAs(Si)-p+GaSb(Si) Esaki diode on a (001) p+ GaSb substrate (ED1). We particularly show the influence of the InAs/GaSb interface nature on both structural and electrical quality. After choosing the right interface stoichiometry between InAs and GaSb, the growth of n+InAs(Si)-p+GaSb(Si) Esaki diode on GaAs is investigated (ED2). In here, 90° misfit dislocations (MDs) array at the GaSb/GaAs interface is used to accommodate the mismatch strain between GaSb and GaAs. After presenting the influence of the growth conditions on the MDs array formation, the electrical results of ED2 are compared to the ones of ED1. This learning is crucial to study the effect of dislocations on BTBT behavior in tunneling devices. In the last step, the integration of n+InAs(Si)-p+GaSb(Si) Esaki diode on (001) Si is presented (ED3) using a 300 mm GaAs on Si template grown by MOCVD. After presenting the detailed growth stack, we demonstrate a high quality n+InAs(Si)-p+GaSb(Si) growth on exactly oriented (001) Si substrate exhibiting a RMS surface roughness of 1.4 nm and a dislocation density (TD) of 9x107/cm2
, as determined by XRD analysis.

In summary, this study gives a broad insight on the influence of different types of defects on the tunneling current. We demonstrate that this learning is crucial for the integration of TFETs onto large area commercial Si substrates.
Scanning Probe Characterization of Memristors Based on a Li Intercalation Metal Oxide
Authors: Fuller Elliot James , El Gabaly Farid , Ware Nicholas , Friddle Raymond William , Hughart David R. , Marinella Matthew J. , Talin Albert Alec
Published: February 2020

Memristor devices are a promising technology to replace CMOS for neuromorphic computing applications. As an alternative to filament-type memristors that require ‘forming’ procedures and which typically exhibit binary ‘on/off’ switching, we are investigating memristors based on a Li ion intercalation oxide LixCoO2. Our devices are composed of simple structures consisting of LixCoO2 films on insulating substrates with top or bottom contacts of Au. The electronic conductivity of the LixCoO2 film strongly depends on the Li-ion concentration and can exhibit synaptic multilevel analog states. However, determining the precise physical mechanisms that give rise to resistive states within a working device remains a challenge. This challenge arises because bulk characterization techniques (i.e. electrochemical impedance spectroscopy (EIS)) can be insensitive to the details of the materials microstructure that are critical to the device behavior. Scanning probe microscopy offers an attractive route to overcome these limitations in order to better understand transport at interfaces and along nanometer length scales. Here, we have carried out in operando Kelvin probe force microscopy (KPFM) on active LixCoO2 memristor devices. Using KPFM, we have directly imaged the potential drops along the device and determined the resistance of the channel versus resistance at the electrode interfaces. By capturing the time evolution of the potential landscape, the ionic and electronic dynamics are separated and their interdependence is revealed. Localized changes in work function suggest regions of Li accumulation and depletion that are associated with particular resistive memory states. The insights we gain from these experiments will guide the fabrication of more complex memristor devices such as row-column addressable arrays.
(Invited) Near-Field Coupling Integration Technology
Authors: Kuroda Tadahiro
Published: February 2020

Invention of IC was driven by “Tyranny of Numbers”, a challenge implied by large number of interconnects in a large-scale system. Modern ICs integrate many miles of wiring and billions of contacts. Moore's Law, however, will die, and we cannot rely just on integration on a chip. A revolutionary solution of the connection problem is now needed for further integration. My proposal, as More-Than-Moore, is to replace mechanical connection using wiring, solder, and connectors by electrical one using near-field coupling. In this presentation, ThruChip Interface by inductive coupling for chip stacking and Transmission Line Coupler by electromagnetic coupling for module connection will be presented and discussed.
(Invited) Hardware Security to Mitigate Threats to Networked More-Than-Moore Sensors
Authors: Obeng Yaw S.
Published: February 2020

More-than-Moore devices (MTM) devices and application platforms have their origin in the convergence of wireless technologies, advancements of microelectromechanical systems (MEMS) and digital electronics.  Such application platforms comprise many small, inexpensive single-function devices and sensors, with varying operating systems, CPU types, memory, etc.  How these devices connect to other devices, and the device-human interfaces, are changing how we work and live.  Hardware security for these interconnected devices is a critical design consideration, just like performance, power, and reliability.   However, due to increased globalization, the whole IC design flow and application phases are distributed world-wide, and the resultant reduced control over the IC life cycle make hardware security a serious concern. For example, hardware security threats in the integrated circuit (IC) supply chain, including hardware counterfeiting and intellectual property piracy cost the US economy more than $200 billion annually. 

This paper examines the current issues pertaining to the hardware security and how they could affect the overall security of MTM applications, such as the internet of things. Specifically, we review the ongoing industry-led activities aimed at mitigating the hardware threats through supply chain assurance.  The paper is illustrated with the ongoing work of the ITRS hardware security working group, the counterfeit risk mitigation efforts from iNEMI, and the High-Density Package User Group (HDPUG), as well as published standards from SEMI and the Open Group.  All these efforts are aimed at mitigating counterfeits in the electronics supply chain through product traceability and authentication. Finally, we will discuss how existing and emerging technologies can be used for product authentication throughout the supply chain.
(Keynote) Challenges of 10 Nm and 7 Nm CMOS for Server and Mobile Applications
Authors: Divakaruni Rama , Narayanan Vijay
Published: February 2020

CMOS scaling has served the semiconductor industry and transformed the world exceedingly successfully over the past several decades.  In recent times, the transition to hi-K dielectric interfaces enabled CMOS to shrink circuits to below the 32nm node. The advent of fully depleted devices (FDSOI, FINFETs) have enabled CMOS scaling to the limits of conventional 193nm optical immersion lithography.

                Over the past decade, CMOS scaling has transformed mobile technologies. The cell phone and smartphone have become ubiquitous as increased performance has been garnered to increase functionality on the form factor at constant power (Watt regime). The resulting boom in data has transformed industries and fueled the social network and the "app" world. 14nm FINFET technology is now available on cutting edge mobile devices. The 10nm node will see various incarnations across the major semiconductor fabricators. The pressure on density to reduce cost will result in the adoption of multiple patterning techniques for the FIN, Gate and various MIddle Of Line (MOL) and Back End Of Line (BEOL) wiring levels. The need to reduce doping in the FINFETs will result in Multi-Workfunction-Gates. Novel materials will be needed to reduce parasitic capacitance and resistance in the MOL and BEOL levels. Some incarnations of the 10nm node will be called "7nm", but the true "7nm" node circuit densities will require the next generation of lithography -- Extreme Ultra Violet (EUV) at 13.6nm wavelength. The key to adoption in the commodotized mobile space is thus the cost of the chip which is challenged by the need for novel cost intensive patterning techniques and new materials.

             While power and form factor are key to the mobile world, Server applications have required performance at much higher power (100+ Watt regime). CMOS scaling has served this market very well over the decades as improved transitors have always been utilized for increased performance (high end servers run > 5 GHz). The growth in the server market has migrated to large datacenters for cloud applications and away from standard transaction processing (which still remains important in many areas). Parasitic  components on FINFETs are thus much more critical in this market and has thus driven early adoption of "next generation" materials and processes. The adoption of 10nm and 7nm nodes in this space will be determined less by cost than by ability to get better performance at constant chip power given the increased parasitics in the MOL and BEOL. This drives the need for introduction of new novel materials for improved performance and reliability.
Vapor Phase Self-Assembled Monolayers for CMOS BEOL Barrier Layers
Authors: Naik Tejas RAJENDRA , Ravikanth M , Rao Valipe RAMGOPAL
Published: February 2020

As the Back - End - of - Line (BEOL) Interconnects are scaling down to nanometer regime with multiple levels of metallization , need for ultra thin diffusion barrier layers arise. Self assembled monolayer (SAM) is an ideal solution to satisfy the requirement of an ultra thin barrier layer to avoid Copper difussion. However, wet chemical processes are preferably avoided in Complimentary - Metal - Oxide - Semiconductor (CMOS) fabrication process. Accordingly , a novel technique to form SAM of Zinc (||) tetraphenyl hydroxy porphyrin (ZnTPPOH) in vapor phase on Inter - Layer Dielectric (ILD) materials is developed in present work to suit the industry process flow and be integreable in CMOS fabrication. The vapor phase SAM formation of ZnTPPOH is investigated employing different techniques and studies from simple contact angle measurements, spectroscopic measurements such as x-ray photoelectron spectroscopy (XPS) , fourier transform infrared spectroscopy (FTIR) , Ultra Violet - Visible Spectroscopy (UV - Vis) , and the atomic force microscopy (AFM) , etc. The vapor phase SAM of ZnTPPOH was formed on different ILD materials such as Black Diamond , Hydrogen silsesquioxane , etc and also on Silicon dioxide substrates. Selective formation of SAM in vapor phase was studied using different substrates such as Gold , Copper , etc .

The vapor phase SAM was incorporated in Metal - Oxide - Semiconductor  Capacitor (MOSCAP) structure. Copper was used as metal and the Vapor phase SAM was formed on Oxide / ILD materials so as to sandwich between the Copper and ILD, to repel and isolate the Copper in order to avoid any diffusion of Copper into the ILD materials. Capacitance - Voltage (CV) measurements , Current - Voltage characterization were done under bias and temperature stress  on the MOSCAP devices to investigate the electrical performance of MOSCAP device and efficiency of ZnTPPOH vapor phase SAM as a barrier layer. Similarly blanket MOSCAP stack was formed and subjected to temperature stress and the extent of copper diffusion was investigated using (SIMS). Scanning electron microscopy (SEM) and scotch tape tests were done to observe improvement in adhesion of Copper to the ILD materials.

The vapor phase SAM process was optimized and devloped to suit the CMOS technology and demonstrated as an effective copper diffusion barrier layer for interconnects. This technique opens up a whole new set of opportunities to scale down the barrier layer thickness. Integrating such bottom-up approach within the CMOS fabrication process would make scaling to 7nm and beyond possible where interface layers, dielectrics, and semiconductor films will be on a molecular level.

Figure 1
(Invited) III-V / Si Integration for Photonics
Authors: Reithmaier Johann Peter , Benyoucef Mohamed
Published: February 2020

In the last decade a large progress took place in the development of a Si-based fabrication technology platform for integrated photonics, however, mainly for passive devices, such as filters, waveguides, splitters and combiners. The integration of active devices remains very challenging. The talk will start with a brief review of different epitaxial approaches for III-V material growth on Si before a new approach will be presented, which may combine high Si process compatibility with full III-V material functionality.

Currently, active photonic devices on a silicon platform are obtained by bonding techniques, either on a single device chip or a full III-V wafer level. However, in this case the majority of III-V material is wasted by substrate removal. Direct epitaxy on silicon overcomes these problems but suffers in most cases from the lattice mismatch and the differences in expansion coefficients. This can be partially accommodated by thick relaxation layers and using quantum dot active regions to reduce the sensitivity against threading dislocations or using complex material compositions, like Ga(N,As,P), which allow lattice matching. However, the III-V layers have to be processed completely separate from the silicon.

A new approach based on III-V-Si nanocomposite is under development, which may overcome most of those problems. This approach is based on the growth of III-V quantum dots (QDs) directly on silicon. Based on a GaAs/InAs core-shell geometry high quality optical emission could be obtained. By overgrowing InAs QDs with silicon a defect free single crystal planar silicon layer can be formed with embedded InAs nano clusters. Transmission electron microscope investigations show that the nanoclusters fully relax by closed loop interface dislocations but without initiating threading dislocations in the silicon matrix.
Comprehensive Characterization of Dual Implanted Silicon after Electrical Activation Annealing
Authors: Yoo Woo Sik , Jeon Bong Seok , Kim Sang Deok , Ishigaki Toshikazu , Kang Kitaek
Published: February 2020

Formation of low resistivity junctions is essential for fabricating high performance devices with advanced device modes. Significant effort has been expended, industry wide, to develop low resistivity junctions, over the years. However, the understanding of implant activation and implant damage recovery process is not sufficient. Development of noncontact implant residual damage monitoring techniques would be beneficial in process development for advanced node devices.  

In this study, we have investigated the effect of annealing temperature and time on the sheet resistance (Rs) of dual (P+ 1.0MeV, 4.0 x 1013 cm-2 + B+ 10keV, 3.0 x 1014cm-2)  implanted p--Si(100) wafers using a single wafer furnace-based (hot wall) rapid thermal annealing (RTA) system over a wide range of annealing conditions (350-800oC, 60-150s). Room temperature photoluminescence (RTPL) spectra were measured from all wafers under two different excitation wavelengths (650 and 785 nm) for additional clues on electrical properties of pn junctions, which cannot be obtained from the Rs measurements. Multiwavelength (457.9, 488.0 and 514.5 nm) Raman characterization was done on all wafers for additional insights on the degree of residual lattice damage, after RTA, under different conditions. After all on wafer measurements were completed, secondary ion mass spectroscopy (SIMS) dopant (P and B) depth profiling was done to assess dopant diffusion during the annealing process.

Rs values showed strong and systematic change with RTA temperature and time, as expected. RTPL spectra also showed large variations in intensity and wavelength distribution corresponding to the RTA temperature and time. Multiwavelength Raman characterization results showed gradual increase of intensity with the RTA temperature. Three regions of different Raman shift values, corresponding to the Si lattice stress and possibly the degree of residual implant damage, were also noted. SIMS P and B depth profiles did not show significant changes. Correlation among characterization results from various techniques and RTA conditions will be presented.