bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Performance Lithium Ion Batteries from Electrochemically Enhanced Conducting-Polymer/Inorganic Composites
Authors: Unur Ece 
Published: February 2020

900 million vehicles meet the road almost every day around the world. 96% of these vehicles depend on combustion engines and thus fossil fuels for energy. Exhaustion of fossil fuels and emission of green house gases motivates the search for alternative energy sources. New environmental regulations enforces governments to support the use of electric vehicles in order to eliminate green house gas emissions and limit dependency on petroleum products. In order to persuade consumers to use electric vehicles some adjustments on the cost and safety must be done. Being the most expensive component of electric vehicles the main research must be focused on lithium ion batteries. Since the research on lithium batteries started to hit the bottleneck, the focus must be shifted to novel, environmentally friendly and cheap materials.
Although, LiFePO4 has been the cathode material of choice (3.5 V vs Li/Li+), its conductivity must be enhanced. Another, material from phospho- olivine family, LiMnPO4, has drawn attention with its high redox potential and thus energy density (~4.1 V vs. Li/Li+). But, it suffers from low conductivity. Silicon being one of the most abundant elements on earth crust and having unbeatable capacity is still the best choice for anode material for high performance lithium ion batteries (4200 mAhg-1). But, it suffers from mechanical degradation taking place due to volumetric changes arising from lithium alloying/dealloying process. Decreasing the particle size and carbon coating has been visited by many scientists to overcome issues of low mechanical stability and conductivity.
In this project; LiMn1-xFexPO4-LiFePO4
cathode will be synthesized by coprecipitation of high potential LiMnPO4 and high performance LiFePO4. Partially lithiated Si will be used as an anode material. Synthesized materials will be coated by PEDOT:PSS to improve their electronic conductivities. Electronic conductivity and plasticity will be further improved by exposing the PEDOT:PSS to a plasticizing agent. Polypyrrole chains (PPy) will be electropolymerized onto PEDOT:PSS surface vertically to present pathways for easy diffusion of lithium ions. These conducting polymers will also aid in the overall capacity of the system.
Conducting polymer-inorganic composite cathode (Al-LiMn1-xFexPO4-LiFePO4-PEDOT:PSS-PPy) and anode(Cu-partially lithiated Si-PEDOT:PSS-PPy) will be combined to form a full lithium ion battery. The battery whose performance is enhanced by conducting polymers is expected to have an OCV of at least 3.5 V and a total energy density of 300 Wh kg-1 . The battery will make 1000 charge/discharge cycles at 1C rate by at least 50% capacity retention and 100 charge/discharge cycles at 10C rate by at least 75% capacity retention.
Effect of Densification Conditions on the Chemical, Electrochemical, and Mechanical Stability of 75Li2s - 25P2S5 (mol %) As a Potential Solid Electrolyte for Use in Electric Vehicles
Authors: Garcia-Mendez Regina , Mizuno Fuminori , Zhang Ruigang , Arthur Timothy S. , Sakamoto Jeff 
Published: February 2020

Solid-state electrolytes have garnered significant attention for their potential to enable solid-state
batteries for electric vehicles with metallic Li as an anode. However, the stability between solid-state
electrolytes and metallic Li is not well understood. Lithium phosphorous sulfides are a promising class of
solid-electrolytes owing to their high ionic conductivity (10-4 – 10-3 S cm-1 at 25 °C), low interface
resistance against metallic lithium, and can be consolidated to > 90 % relative density at room
temperature1 . In this work, the chemical, electrochemical, and mechanical stability of hot-pressed 75Li2S-
25P2S5 (mol %), or LPS, between 200 and 550 °C was investigated. Hot pressing produced high relative
density and crystalline LPS pellets that were characterized using multiple electrochemical techniques. AC
impedance measurements were used to characterize the stability of the Li-LPS interface. The
electrochemical performance of LPS was analyzed as a function of current density between 0.01 and 1.0
mA cm-2 followed by cross-sectional microstructural analysis. It will be shown that: i) below or equal to
0.05mA cm-
2 ohmic behavior is observed, ii) at 0.1mA cm-
2 a transition behavior occurs identified by an
instability in polarization, and iii) above or equal to 0.5mA cm-2 , the potential decreases and is believed to
be related to the formation of an electronically conducting phase. Acoustic impulse excitation
measurements were used to determine changes in the elastic constants after DC cycling of Li-LPS.
Additionally, materials characterization such as Raman, XRD, and SEM will be presented to correlate the
densification conditions with DC cycling stability. We believe this is one of the first studies to
characterize the chemical, electrochemical, and mechanical stability of a Li-LPS interface. The
methodology established in this work could be applied to other solid-state electrolytes as well.
Reference

Sakuda, Atsushi, Akitoshi Hayashi, and Masahiro Tatsumisago. "Sulfide solid electrolyte with favorable mechanical property for all-solid-state lithium battery."Scientific reports 3 (2013)
(Invited) Reactions of Positive Active Materials of Lib
Authors: Ogumi Zempachi , Arai Hajime , Orikasa Yuki , Uchimoto Yoshiharu 
Published: February 2020

Main issues for lithium ion batteries (LIBs) to grow in the application to advanced vehicles are durability, safety and cost. The durability is closely connected with safety, cost, energy density, etc.
LIBs are constructed by composite electrodes both of positive and negative electrodes, which are composed of pulverized active materials, conductive additives, and binders. The structure of LIBs is thus complicated and reaction distribution inside battery and composite electrodes often occurs. Uniform reactions distribution leads to the maximum performance of the battery. Many factors give major influences on the reaction distribution. Analytical methods to elucidate the reaction distribution were limited. In RISING project, different kinds of operando analytical technologies were developed. In the present work, some methods using SR X-ray devised in RISING are introduced and reaction distributions clarified by using this technology are explained mainly on positive electrode of layered and olivine type materials.

Acknowledgment

This work was supported by RISING of NEDO.
(Invited) Low-Temperature Microwave-Based Plasma Oxidation of Ge and Oxidation of Silicon Followed by Plasma Nitridation
Authors: Lerch Wilfried , Schick T. , Sacher N. , Kegel W. , Niess J. , Czernohorsky M. , Riedel Stefan 
Published: February 2020

Oxidation is a key process step in semiconductor device fabrication. Oxides are widely used in the production process as gate dielectrics, interfacial layers for high-k deposition, pad oxides, sacrificial oxides, screen oxides, protection oxides etc. Even though the used oxide thicknesses become thinner the thermal budget (roughly time at temperature) is generally not scalable with the thickness decrease due to the thermally activated oxidation process. However, for future sub-22 nm device structures a continuous reduction of oxidation temperatures is required to minimize dopant redistribution or deactivation, boron depletion, and oxidant enhanced diffusion effects. At the same time physical, chemical and electrical oxide quality has to be maintained. This is valid also for all process steps after device formation where high quality oxides are needed. BEOL applications like surface conditioning by oxidation is only one example.
In this contribution we show that oxides can be grown and/or in a subsequent process step nitridized with an excellent electrical quality for planar Si and Ge devices but also conformally on 3D Si devices at very low temperatures (T < 400 °C). First the oxide growth with or without subsequent nitridation as a multi-step process is studied as function of time, and gas ambient on silicon and germanium, second the electrical characteristics of these various films are demonstrated. In the industry Ge is expected as the promising channel material for future CMOS because of its highest hole mobility among common elemental and compound semiconductors, and an electron mobility that is two times larger than that of Si. Therefore it is important to show outstanding electrical results of the Ge passivation layers grown at very low temperatures.
High-K Metal-Gate Nanowire Junctionless FinFET with Nickel Silicide by Microwave Annealing
Authors: Tsai Wan-Ting , Lin Yu-Hsien 
Published: February 2020

Background/ Objectives and Goal

Silicide techniques are widely used for high-performance logic devices as the device dimensions become small towards sub-100 nm due to the source / drain sheet resistance issue.NiSiprocess has several advantages.They are (1) low temperature silicidation process, (2) low silicon consumption, (3) no bridging failure property, (4) smaller mechanical stress, (5) no adverse narrow line effect on sheet resistance,and(6) smaller contact resistance for both n- and p-Si[1].We, therefore, propose a nickel silicide junctionlessFinFETdevices.
2. Methods

Fig.1. depicts schematically view of the high-K metal-gate nanowire junctionlessFinFETwere fabricated on a 6-inch wafer with a 40 nm-thick silicon dioxide layer.The active layer with ten strips of NWs was defined by electron beam (e-beam) and transferred by reactive ion etching.An 33 nm dry SiO2 layer was grown on the active layer. Next,implanted (boron for pFETs and phosphorus for nFETs,dosage of 2 × 1014 cm2) and followed by thermal anneal in the channel.The samples were then dipped in HF solution for NWs. 3 nm of HfO2was deposited by ALD on the nanowires as gate dielectric, followed by the PVD 50 nm TiN for gate metal.After the deposition,electron beam (e-beam) defined gate contact and transferred by reactive ion etching.Next, 15 nm of titanium followed by 15 nm of nickel was deposited on the sample.NickelSilicide was formed after twice microwave anneal.First annealed by microwave with 360W for 300 sec , and1300W for 300sec. The temperature profiles versus annealing time are shown in Fig. 2[2].
3. ExpectedResults/Conclusion/Contribution

The ID–VGcharacteristics of a 15 nm gate-length high-k metal-gate nanowire junctionlessFinFET Fig. 3.The on-current value is comparableto that of a junctionlessfinfetwith the same bias conditions.In our experiment,there was no metallization past the silicide layer, therefore the resistance of the devices was large.This is the reasons why devices without silicide showed less on-current presented here.
We have demonstrated high-k metal-gate nanowire junctionlessFinFET with nickel silicide fabricated with a low-temperature process.The devices have exhibited a competitive short-channel behavior and a much-improved drive current.These results indicate that silicide S/D is a promising option for a nanowire junctionlessFinFET device.We believe that this letter significantly advances the state of the art for low-temperature silicide junctionlessFinFET.

REFERENCES

[1] H. Iwai, T. Ohguro, and S. Ohmi, “NiSi salicide technology for scaled CMOS,” Microelectron. Eng., vol. 60, no. 1/2, pp. 157–169, Jan. 2002
[2] Y.-J. Lee et al., “Low-temperature microwave annealing processes for future IC fabrication—A review,” IEEE Trans. Electron Devices, vol. 61, no. 3, pp. 651–665, Mar. 2014.

Figure 1
Novel Oxidants and Sources of Nitrogen for Atomic Layer Deposition
Authors: Alvarez Daniel , Spiegelman Jeffrey , Heinlein Ed , Holmes Russell , Ramos Chris , Leo Mark , Webb Sean 
Published: February 2020

Significant effort has gone into developing novel metal precursors for Atomic Layer Deposition (ALD). This effort has been primarily driven by the industry need for new high K materials and metals films. The need for novel oxidants and sources of nitrogen has been largely ignored. This paper focuses on delivery of anhydrous hydrogen peroxide and anhydrous hydrazine for ALD applications.
Hydrogen Peroxide (H2O2) in aqueous form is commonly used in semiconductor manufacturing for cleaning and surface preparation operations. Thirty percent and fifty percent two-component mixtures have been investigated in a few ALD studies with moderate success. Especially noteworthy are Kummel’s findings that the use of hydrogen peroxide leads to a 3x increase in nucleation density on Ge versus water. However, H2O2 has limited general utility in aqueous form due to the volatility of water. At 30C, Raoult’s law predicts a headspace concentration of 294ppm H2O2 and 32373ppm for water, where the H2O/H2O2 ratio is over 100. Clearly these are not optimal conditions for hydrogen peroxide ALD. However, in its pure state, hydrogen peroxide is highly unstable and has a propensity to decompose, forming water and oxygen. Our approach entails the use of a membrane delivery system where 99.6% hydrogen peroxide is dissolved in an organic solvent. Hydrogen peroxide permeates the membrane and is delivered to the ALD chamber, while the solvent does not permeate and remains in the liquid state. In this way, concentrations much higher than predicted by Raoult’s law for aqueous mixtures are delivered to the process chamber in the absence of water.
Next generation devices have low thermal budgets and high aspect ratio structures that create new challenges for ALD grown nitride films. The use of ammonia is limited due to temperature constraints. Known Plasma methods cannot uniformly coat the side walls of the device structures and create surface damage. Hydrazine (H2NNH2) has been proposed as a thermal ALD low temperature nitride source. Hydrazine is highly flammable and its flash point decreases with reduced water content. In an analogous approach, we have developed a new method and formulation for the delivery of anhydrous Hydrazine by the use of an inert organic solvent and membrane delivery system. Precursor vapor pressure is maintained at levels viable for ALD. Moreover, the addition of a high boiling solvent lowers the risk of explosion by raising the solution flash point.
Preliminary ALD data will be presented showing unique properties of these new precursors along with theoretical data on precursor delivery under variable ALD conditions.
(Invited) Rapid In-Situ Carbon and Oxygen Cleaning of In0.53Ga0.47As(001) and Si0.5Ge0.5(110) Surfaces via a H2 RF Downstream Plasma
Authors: Wolf Steven , Edmonds Mary , Jiang Ximan , Droopad Ravi , Yoshida Naomi , Dong Lin , Galatage Rohit , Siddiqui Shariq , Sahu Bhagawan , Kummel Andrew 
Published: February 2020

Channel passivation of SiGe and InGaAs requires removal of dangling bonds and formation of a thermally stable interface. On InGaAs, one solution is the deposition by self-limiting CVD or ALD of a few monolayer of silicon, silicon oxide, or silicon nitride. To form an Si-OH terminated In0.53Ga0.47As(001) surface, two monolayers of Si were deposited at 350°C with self-limiting CVD using Si2Cl6 dosing following by dosing anhydrous HOOH(g). Scanning tunneling microcopy (STM) shows and ordered surface is form while scanning tunneling spectroscopy (STS) shows the surface Fermi level position moves towards midgap due to a surface dipole formation from –OH groups and oxygen bonding to the surface. TMA was dosed at 250°C onto the Si-OH terminated InGaAs(001), and XPS shows the emergence of the Al 2p and C 1s peaks indicative of TMA surface nucleation. The TMA shifts the InGaAs Fermi level back towards the conduction band, consistent with unpinning. MOSCAPs were fabricated to further demonstrate Fermi level unpinning using the Si-OH termination of InGaAs.
While this same Si deposition process could be employed on SiGe, a simple annealing process can be employed to form a silicon terminated SiGe surface. A saturation dose of H2O2(g) at 25oC chemisorbs to on Si0.5Ge0.5(110) and Si0.47Ge0.53(001) surfaces leaving the Fermi level on the surface unpinned, and the surface is functionalized with mainly Si-OH, Ge-OH and Si-O-Ge bond. After a subsequent TMA dose at 25oC and annealing at 300oC, XPS and STM verify that a thermally stable and well-ordered monolayer of Al2O3 is formed on SiGe(110) and (001) surfaces with only Al-O-Si bonds and no detectable Ge-O-Si bonds. The H2O2(g) functionalization provides 3 times higher O sites on the surface and 3 times higher TMA nucleation density than H2O(g) at 25°C and 120°C.
A variety of strongly bound passivating atoms can induce formation of a nearly pure Si interfacial layer between high-k dielectrics and SiGe. This annealing procedure was employed to form MOSCAP on SiGe(001) using Al2O3 and HfO2 gate oxides after either (NH4)2S or NH3 plasma passivation. For NH3 plasma passivation, angle-resolved XPS showed that the annealing allows formation of nearly Ge-free SiON layer. For higher Ge concentrations, the annealing process is unlikely to form a nearly Ge-free SiON layer so a novel plasma-free chemistry has been develop to deposit SiON using ALD with N2H4(g) as a precursor.

Figure 1
Comparison of SiNx and AlN Passivations for AlGaN/GaN Hemts
Authors: Yang Song , Lei Lei , Yu Kun , Zhang Anping , Chen Kevin J 
Published: February 2020

We present a comparative study of suppressing AlGaN/GaN HEMTs’ current collapse by two types of passivation materials: amorphous SiNx (grown by PECVD and LPCVD) and epitaxial AlN (grown by plasma enhanced atomic layer deposition (PEALD). The motivation of this study stems from the different mechanisms underlying the two passivation techniques, namely, surface-charge-compensation by shallow donors (with SiNx) and polarization charge (with epitaxial AlN). Since de-trapping from the shallow donor levels is a time-dependent process and the polarization charge compensation is a time-indepdent phenomenon, AlN-passivated AlGaN/GaN HEMTs was found to exhibit improved dynamic switching behavior than SiNx-passivated devices. The results show that the depletion region is much narrower in AlN-passivated devices than SiNx-passivated and un-passivated devices. The transient characteristics reveal the superiority of AlN passivation as the formation of depletion region is predominantly a field effect while the de-trapping from the shallow donor levels in SiNx-passivated devices is limited by their intrinsic time constant. AlN-passivated devices show much smaller dynamic RON variation under both fast and slow switching operations.
(Invited) Development of β-Ga2O3 Materials
Authors: Speck James 
Published: February 2020

β-Ga2O3 has attracted significant recent attention for its large bandgap of 4.8 eV which leads to a high breakdown electric field, predicted to be 8 MV/cm. With a predicted maximum bulk electron mobility of 300 cm2/Vs, β-Ga2O3 yields a Baliga figure of merit (BFOM) that is higher than that of 4H-SiC and GaN. β-Ga2O3 has a monoclinic crystal structure (usually represented with the b-axis as the unique axis) with strong anisotropy in physical properties. The crystal cleaves easily on the (100) and (201) planes. MBE growth on cleavage planes yields low growth rates due to a strong propensity for Ga loss via suboxides [M.-Y. Tsai et al., J. Vac Sci. Tech. A 28, 354 (2010).]. Growth on non-cleavage planes, such as (010), however, yields high growth rates [K. Sasaki et al., J. Cryst. Growth 378, 591 (2013).]. In this presentation, we review our work on development of growth of β-Ga2O3 (010) by plasma-assisted MBE. We present the development of high temperature homoepitaxial growth of β-Ga2O3 (010) and preliminary Sn doping [H. Okumura et al., Appl. Phys. Express 7, 095501 (2014)]; the development of coherent β-(AlxGa1-x)2O3/Ga2O3 heterostructures [Kaun et al., J. Vac. Sci. Tech. 33, 041508 (2015)]; and viable RIE and ICP etch processes [J. Hogan et al., in preparation].
The SnO2 nanowires Synthesis and Characterization
Authors: Lu Fang-Chun , Wang Chiu-yen 
Published: February 2020

Tin dioxide (SnO2) nanowires grow by the thermal vapor deposition method. Vapor-liquid-solid method grows nanowires to product uniform nanowire’s diameter, because this method can control nanowire’s diameter. There are many parameters to affect the nanowire’s growth. These parameters are temperature (source area), flow rate, pressure, source mass, grow time, distance between the source and growth area and the thickness of gold films. The purpose of this study is to find the relationship between the nanowire’s growth and these parameters. Also, by using these parameters to grow the nanowires with specific size of diameter and length.
We find the suitable condition to grow the nanowires and the relationship between growth condition and effect of parameters. This condition grows nanowires is controllable and can be reproduced. In SEM images, it shows the straight nanowires with uniform diameter is 60~120 nm. Here, we discuss the effect of the temperature (source area), flow rate, pressure, source mass…etc. The temperature influences the precursor’s vapor pressure: when the temperature is high, the vapor pressure will be increased and will be caused nanowire to be dense. Similarly, precursor’s mass also affects the density of NWs. Because more precursor will supply more vapor at the moment, it let the density to increase. The growth time is the parameter to control the nanowire’s length when it supplies enough precursor. Pressure, gas flow rate and distance which determine the nanowires grow or not. Nanowires will grow only at the suitable environment. The thick of gold film which controls the nanowire’s diameter, because we grow the nanowires by VLS mechanism. In this study, we can get the specific SnO2 nanowires by tuning growth parameters, such as length, diameter, density ...etc. So it’s possible to support the suitable SnO2 nanowires to make the semiconductor devices.