bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Combined Gas Cluster Ion Beam (GCIB) and Chemical-Mechanical Planarization (CMP) Process for Replacement Metal Gate (RMG) Application
Authors: Tseng Wei-Tsu , Long Justin , Mohan Kaushik , Wu Changhong , Kagalwala Taher 
Published: February 2020

The introduction of high-k metal gate (HK/MG) stack has enabled the resumption of Moore’s Law at the 45/32nm nodes, when the conventional Poly/SiON gate stacks failed to meet the required scaled-down performance targets. Despite the well demonstrated benefits such as reduced gate leakage, HK/MG integration scheme itself brings about new challenges in Si-based semiconductor process technologies. Among them, the most critical and stringent step is RMG CMP, which is tasked to deliver gate height uniformity within the range of a few nanometers on all chips across the entire 300mm wafer for 14nm technology nodes and beyond.
Conventional approaches to CMP planarity and uniformity often include the optimization of carrier zone pressure, platen/carrier rotation, slurry flow, conditioning sweep profileetc. Advances in CMP equipment technologies have also enabled new possibility such as multi-zone carrier pressure control through APC for within-wafer non-uniformity (WiWNU) reduction. Another widely-adopted approach is to rely on the high-selectivity of slurries to “stop dead” on the final layer of interests (e.g., tungsten in the case of RMG) without creating excessive local topography due to oxide erosion. While all the above approaches prove effective to certain degree, they are, by nature, wafer-level to sub wafer-level processes. As a consequence, it is difficult for them to differentiate between dies locally, for example, and correct the non-uniformity accordingly to the range of a few nanometers.
In this contribution, an alternative planarization scheme for RMG is presented to enable nano-scale gate height uniformity control across all dies on 300mm wafers. The new scheme begins with conventional high-selectivity CMP process (pass-1 W-CMP) to remove overburden and polish the gate height down to a few nanometers thicker than the final target, followed by all-die gate height measurement on all wafers. Then the gate height data are fed forward to a GCIB tool, where location-specific process (LSP) takes place to trim the oxide down to a pre-determined target, die by die, through high-energy raster ion beam with high oxide-to-tungsten selectivity. This is followed by a final tungsten touch-up CMP process with high tungsten-to-oxide selectivity to level off the protruded metal patterns and drive the gate height to final target.
Applied to SOI-based deep-trench (DT) and FINFET integrated wafers based on 14nm ground rule, the new RMG planarization scheme above demonstrates supreme gate height uniformity. Gate height WiWNU reduces continuously from ~ 2.95% post pass-1 W-CMP to 1.85% post GCIB, and to 1.51% post T/U CMP. The 3sigma of gate height across all dies on 300mm wafers is less than 3nm. The underlying mechanism to achieve nano-scale planarity and uniformity control by this new planarization method will be discussed.
(Invited) Deep Silicon Etching Increasingly Relevant >20 Years on!
Authors: Thomas Dave , Muggeridge Matthew , Hopkins Janet , Launay Nicolas , Ashraf Huma , Barrass Tony 
Published: February 2020

In the early 1990’s researchers at the Robert Bosch facility in Stuttgart invented a novel method of etching very deep features into silicon. This led to a patent being granted in 1994. Subsequently (and still) referred to as the ‘Bosch’ process it was first licensed to SPTS who shipped the first commercial systems in 1995. Originally intended as a method of fabricating devices for the then emerging automotive MEMS sector, its use has since diversified to cover virtually all other MEMS markets. Most recently the use of the Bosch Process has expanded into through silicon via (TSV) etching in 3D packaging applications. In 2014 in Amsterdam the inventors (Franz Laermer and Andrea Urban) were awarded the IEEE Jun-Ichi Nishizawa Medal for revolutionising MEMS by enabling the proliferation of many of the everyday devices that surround us today (such as the inertial sensors in airbags and various chip-sets in smart phones, gaming consoles and laptop computers).
This paper will describe what is possible today using the Bosch process and will consider future applications and uses. The diversity of the approach will be illustrated through various examples including cavities etched at high rates, features with aspect ratios of 90:1, profile tilt to <0.2°, TSVs for wafer stacking and the increasing demand for more precise control including end-point detection below 0.5% open area. The types of devices that require such performance will also be discussed – everything from inertial MEMS, integrated passives, microphones, power semiconductors, microphones, interposers and stacked memory die. The relevance of the Bosch process to newer application areas such as die singulation and BioMEMS will be discussed. The developments in reactor designs necessary in achieving these advancements will also be reviewed.
The longevity of the Bosch approach is in part due to the lack of alternative methods able to achieve the same results in Si. A brief comparison with the competing technologies of wet chemical etching, single step plasma etching, cryogenic etching and LASER drilling will be presented.
300mm wafers are in routine use for Bosch etching of TSVs as part of advanced wafer level packaging integration schemes. However 300mm wafers are now also being considered for MEMS to maximise the die per wafer or to allow direct bonding and integration of MEMS functionality with the best available CMOS chip-sets. The latest results for deep silicon etching of 300mm will also be presented.
Li2CO3 As an n-Type Dopant in Enhancing the Electron Injection of Organic Light-Emitting Devices
Authors: Liu Ya-han , Tsai Chi-Ting , Chu Sheng-Yuan 
Published: February 2020

In this article, we demonstrated the OLED incorporating a transport layer composed of lithium carbonate (Li2CO3) doped into the 2-methyl-9, 10-di (2-naphthyl) anthracene (MADN) as electron injection material. In our devices, an OLED with n-doping structure ITO/NPB (40nm)/Alq3 (40nm)/Li2CO3: MADN (5nm, 25%)/LiF (1nm)/Al (140nm) accomplished maximum luminance of 20760 cd/m2 and current efficiency of 4.878 cd/A. By contrast, the device without doping Li2CO3 ITO/NPB(40nm)/Alq3 (40nm)/ MADN (5nm)/LiF (1nm)/Al (140nm) achieved a maximum luminance of 15530 cd/m2 and current efficiency of 3.922 cd/A. The device of the standard one ITO/NPB(40nm)/Alq3 (40nm)/LiF (1nm)/Al (140nm) only achieved a maximum luminance of 18450 cd/m2 and current efficiency of 3.134 cd/A.
The experiment results show that the transport layer with appropriate doping can efficiently enhance the electron injection, leading to more balanced concentration of electrons and holes. Compared with the standard sample, the maximum luminance and current efficiency are increased by12.5% and 55.6%, respectively.

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(Invited) Employing Electrophoretic Deposition in Biomaterial Processing
Authors: Tayebi Lobat 
Published: February 2020

Manipulation of biomaterials including biomedical polymers/ceramics, collides, cells, proteins and enzymes using electrophoresis deposition (EPD) method is the focus of this presentation.
The deposited layers by EPD can be highly homogeneous with microstructural uniformity. Their thickness is controllable and the coating can be applied in complex three-dimensional (3D) structures such as the 3D-printed scaffolds produced for tissue engineering applications.
Three characteristics of EPD make this technique very attractive for different biomedical applications: 1) high adaptability, 2) low cost and simple experimental set up and procedure, and 3) scaling up capability.
The interest in the general applications of EPD in material processing has been extensively increased during the last decade, with emphasis on employing EPD for nanomaterials and biomaterials.
Coating of hydroxyapatite (HA) Ca10(PO4)6(OH)2 on Titanium substrate by Ducheyne et al. in 1986 can be considered as an initial step toward employment of EPD in biomaterial processing. Since then, there were valuable attempts for developing various nanocomposite coatings on biomedical constructs including 3D porous structures. Most of these constructs were originally designed for orthopaedic applications.
Recent expansion of the EPD biomedical application includes improvements in tissue engineering scaffolds, biosensors, drug delivery systems and different functional thin films. The use of EPD to produce biofilms is being progressively investigated recently.
EPD as an advanced electric field-assisted deposition method can now be employed for coating of carbon nanotubes (CNTs), bioactive particles, and biological objects such as proteins on biomedical constructs and devices.
This talk will present a summary of the relevant works during the last decade describing the use of EPD in biomaterial processing and biomedical applications.
Reversible Assembly of Colloidal Particles Using Low Frequency Pulsed DC Electric Fields
Authors: Lee Elaine , Dudoff Jessica , Coe Hannah , Giera Brian , Pascall Andrew J. , Worsley Marcus A. , Kuntz Joshua D. , Zepeda-Ruiz Luis 
Published: February 2020

We present the reversible assembly of colloidal nanoparticles in organic solvents using low voltage and low frequency pulsed DC electric fields. Commercially available and custom nanoparticles (diameter ~ 50-200 nm) were suspended in organic solvents at concentrations of 0.25-50 wt% and sandwiched between indium tin oxide (ITO) electrodes of spacing 25 μm-2mm. Using square waves of frequency 0.25-5 Hz, voltages 0.5-5V, and DC offset 0.25-2.5V, colloidal suspensions were actuated for switchable contrast. Upon switching off the electric field, the assembled nanoparticles are able to resuspend within seconds. Using patterned electrodes, lateral electromigration of the particles was demonstrated. Depletion of the particles to the electrode regions resulted in transparency in the non-patterned regions. The distinct contrast generated can be exploited for tunable display applications.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-679931.
Enhanced Rate Performance of Li-S Batteries Enabled By Polysulfide Reactions
Authors: Wu Nae-Lih , Lee Rung-Chuan , Jin Jian-Ting , Fang Jason 
Published: February 2020

Lithium-sulfur (Li-S) battery is a promising rechargeable battery system that has both high theoretical capacity and energy density. Moreover, sulfur (S) is inexpensive and nontoxic, making Li-S suitable for large-scale energy storage applications. Sulfur (S8) lithiation during the operation of Li-S battery is a multi-step electrochemical process that involves different lithium polysulfide (Li2Sn, 1…n…8) intermediates. The long-chain polysulfides (PSs) are highly soluble in the aprotic organic electrolyte. There has been a broad consensus that PS dissolution is directly linked to the deterioration of several key performance indexes, such as cycle life, self-discharge and coulombic efficiency, of the battery. However, it is demonstrated in this presentation that the PS dissolution process could have a profound effect on the rate capability of the Li-S battery.
It is shown that solution reactions among the PSs take place concurrently with the electrochemical reactions occurring at the solid surfaces. Surprisingly, with properly designing the electrode structure, one can take advantage of the PS solution reaction pathways to substantially enhance the rate capability of a Li-S battery. The following figure compares the rate performance of two Li-S cells that contain the same S-C composite particles having 45% S content but different electrode design. The two electrodes showed dramatically different rate performance.

Figure 1
Long-Time and Reliable Gas Monitoring in Li-O2 Batteries Via a Swagelok-Derived Electrochemical Cell
Authors: Lepoivre Florent , Grimaud Alexis , Larcher Dominique , Tarascon Jean Marie 
Published: February 2020

Over the past decades, many scientific discoveries in material science have allowed Li-ion batteries to become the most effective way to store energy in portable devices. However, their implementation in more demanding applications such as long range electrical vehicles requires an increase of their energy density. The quest towards better performances is exploring alternative technologies, such as the Lithium-Oxygen (Li-O2) technology, which offers a very high theoretical capacity [1]. Non-aqueous Li-O2 batteries lie on the overall electrochemical reaction: 2 Li + O2 (g) ↔ Li2O2 (± 2 e-), which enlists the reversible uptake and removal of one mole of dioxygen every 53.6 Ah (corresponding to 2 moles of electron). Although the reaction is simple, mastering the Li-O2 chemistry remains an enormous challenge. This calls for a better understanding of fundamental mechanism of the overall chemistry. It involves the monitoring of gaseous species which requires the development of unconventional tools enabling an accurate investigation of these battery systems.
This need was an impetus to design a new electrochemical cell as reported herein. It integrates a pressure sensor enabling to accurately monitor with high reproducibility and sensitivity in operando pressure changes during charge/discharge without disturbing the cell system [2]. Its friendly use is demonstrated by quantifying the amount of parasitic reaction in Li-O2 cells based on a carbon cathode with various electrolytes frequently encountered in the literature, such as LiTFSI in DME, DEGDME and TEGDME; LiNO3 in DMA [3], and LiClO4 in DMSO. Through this comparative study based on pneumatic data, we were able to easily observe the phenomena currently limiting the performances of Li-O2 batteries such as electrolyte instability, oxidation of the carbon electrode and the role of impurity contamination [4]. Moreover, aging of such cells was investigated, showing for all systems a formatting process occurring during the first cycles, hence the importance of the set-up reported herein enabling easy gas monitoring over unlimited number of cycles.
Finally, this technology is directly transferable to the study of every material whose electrochemical behavior enlists gas uptake and release such as Li-rich layered compounds [5], organic electrode materials and other metal-air batteries.
1 P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J.-M. Tarascon, Nat. Mater., 2012, 11, 19–29.
2 F. Lepoivre, A. Grimaud, D. Larcher and J.-M. Tarascon, Submitted, 2015.
3 V. Giordani, W. Walker, V. S. Bryantsev, J. Uddin, G. V. Chase and D. Addison, J. Electrochem. Soc., 2013, 160, A1544–A1550.
4 K. U. Schwenke, S. Meini, X. Wu, H. A. Gasteiger and M. Piana, Phys.
Chem. Chem. Phys., 2013, 15, 11830.
5 E. McCalla, A. S. Prakash, E. Berg, M. Saubanère, A. M. Abakumov, D. Foix, B. Klobes, M.-T. Sougrati, G. Rousse, F. Lepoivre and others, J. Electrochem.
Soc., 2015, 162, A1341–A1351.

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Characterization and Electrochemical Performance of Nanostructured Transition Metal (M= Fe, V, Mn) Oxides for Sodium-Ion Batteries Oral Presentation
Authors: Ellis-Terrell Carol Ann , Rhodes Christopher , Perera Sanjaya , Niu Sibo , Archer Randall 
Published: February 2020

As the battery technology field continues to grow rapidly into applications such as electric vehicles and stationary energy storage, there is a need for alternative rechargeable batteries. Although lithium-ion batteries have recently dominated the rechargeable battery market, there are serious concerns regarding the limited availability and cost of lithium. (1) Sodium-ion batteries (SIB) offer an alternative to traditional lithium-ion batteries (LIB) as they have the potential to be lower cost and provide comparable capacities. Electrodes that provide high capacities, voltages and reversibility are required for developing high performance SIBs. The larger ionic radius of Na-ions compared to Li-ions requires electrode materials that can reversibly accommodate the larger Na-ions. Nanoscale materials have been shown to be a promising route to provide improved electrodes for Na-ion batteries.(2) Our group has investigated transition metal compounds (MXy, M=V, Fe and Mn and X=O) where the nanoscale structure presents a unique structural design in which two-dimensional materials are produced. The shape, sizes and composition of the metal oxide materials can be controlled. In this talk, we will present the synthesis, structure and electrochemical performance of nanostructured metal oxide cathodes for sodium-ion batteries.
1). M.D. Slater, D. Kim, E. Lee, C.S. Johnson, Adv. Funct. Mater.
2013, 23, 947-958.
2). J. Zhu, D. Deng, Angew. Chem. Int. Ed.
2015, 54, 3079-3083.
Transition Metal Oxide Nanosheets for Improved Performance Li-Ion and Mg-Ion Cathodes
Authors: Rhodes Christopher , Perera Sanjaya , Archer Randall , Niu Sibo , Ly Carol 
Published: February 2020

Next generation batteries needed for numerous consumer and vehicular applications require improved electrochemical charge storage materials that have higher capacities, improved rate capabilities, and longer cycle lives. Nanosheets consisting of atomic two-dimensional (2D) layers have a number of key features for cathodes including rapid surface-based charge storage rather than intercalation, quantum confinement in two dimensions, and the ability to accommodate substantial structural changes during insertion/de-insertion. We have explored transition metal (M=V, Fe, Mn) oxide nanosheets to provide improved cathodes for Li-ion and Mg-ion batteries. Synthesis conditions were controlled to obtain nanosheets with controlled sheet sizes, phase, and aggregation. Temperature treatments were found to significantly affect the electrochemical charge and discharge capacities with in some cases lower temperature treatments providing improved performance over higher temperature treatments. Using different drying conditions was explored as a route to maintain largely distinct nanosheets and prevent nanosheet restacking which facilitates the storage of larger cations (e.g. Mg-ions). Obtaining oriented nanosheets through using substrate interactions and applied fields was investigated to increase the electronic conductivity and improve the rate capabilities. The ability to control the structure and properties of transition metal oxide nanosheets provides a route to cathodes with improved capacities, rates and cycle life.
Stabilization and Functionalization of P4332 Type LiNi0.5Mn1.5O4 By Incorporation with Cu2+ Substitution and Characterization of Their Electrochemical Properties
Authors: Zettsu Nobuyuki , Shiiba Hiromasa , Satoshi Kida , Teshima Katsuya 
Published: February 2020

We studied the phase stability of P4332-type LiNi0.5Mn1.5O4-

d

phase through the substitution of transition-metals by using ab initio DFT calculations as well as flux growth of their single crystals. Computational studies reveal that small quantities of Cu2+ substitution into Mn2+ site stabilizes LiNi0.5Mn1.5O4-

d

crystalized into P4332 lattice as compared to that of Fd-3m. Furthermore, Cu2+ substitution enhances its electronic conductivity through the d-electron doping effect and reduces activation energy for the Li+ transfer. As predict computationally, flux grown LiNi0.49Cu0.01Mn1.49O3.62 single crystalline particle-based composite electrodes show flat plateau in their charge-discharge curves at around 4.7V (vs Li+/Li) arose from the Ni2+/Ni4+ redox couples, and showed higher specific capacity of ca. 140 mAh/g under operation with current density of 0.2 C. And cyclic voltammetry, Raman spectroscopy, TEM coupled with SAED, and Rietvelt confinement reveals the LiNi0.49Cu0.01Mn1.49O3.62 particles are crystallized into highly ordered P4332 lattice. Interestingly, C rate and high voltage capability are also enhanced significantly with no any assistance of additives. More than 70% of original discharge capacity is retained under operation with current density of 10C. And 96 % of original discharge capacity is retained after 100 cycle charge-discharge test with cut-off voltage of 4.8-3.5V.
Molten Salt Synthesis of Transition Metal Oxides Modified Li4Ti5O12 As Anode Material of Li-Ion Battery
Authors: Guo Qingjun , Li Bing 
Published: February 2020

In order to meet the requirement for the rapid development of electric vehicles (EVs) and hybrid electric vehicles (HEVs), lithium-ion batteries (LIBs) with high safety, high stability and high energy are urgently needed. Spinel-type Li4Ti5O12 (LTO) has become the most promising anode material of the LIBs used in EVs and HEVs as its’ zero variation. However, LTO intrinsically insulative character, and large polarization at high rates restrict its high energy and power density. Our study focuses on increasing the specific surface area and electron conduction through thimbleful transition metal oxides (Fe2O3, Fe3O4, Co3O4) modifying LTO bymolten salts synthesis method.
Transition metal oxides not only decrease greatly on particle size, but also enhance the electrochemical performances of LTO and the reaction mechanism is investigated. Transition metal atoms as the interstitial and substitutional atoms homogenously distributes in the crystal lattice of LTO. The optimal modified LTO exhibits a excellent first discharge capacity of 269.3 mAh g-1 at the 0.1 C and 201.3 mAh g-1 at 1 C; good high rate capability (123.4 mAh g-1 at 12 C). Doping increases nucleation sites during LTO formation in molten salts which reduces the particle size of LTO. Substituted atoms expand the paths for Li+ de/ intercalation and cause O32e or Li8a,16d vacant sites which improves the electronic conductivity of LTO. These findings indicate thimbleful metal oxides doping as an effective method to improve LTO performance by use of molten salt method which can use on the industrial production.

KEYWORDS:
molten salt, transition metal oxides, Li4Ti5O12, anode material, lithium-ion battery