bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Effects of Ge Substrate Annealing in H2 on Electron Mobility as well as on Junction Leakage in n-channel Ge MOSFETs
Authors: Toriumi Akira , Lee Choonghyun , Nishimura Tomonori 
Published: February 2020

A significant enhancement of electron mobility and understanding of carrier transport physics in Ge MOSFETs have been made thanks to significant reduction of major extrinsic carrier scattering sources such as Dit
and surface roughness, in addition to EOT scaling in Ge gate stacks. Since the phonon scattering is the dominant mechanism in Ge bulk, Ge substrate considerations have been out of scope for improving the carrier mobility in Ge MOSFETs. In this talk, however, we report that the peak electron mobility is dependent on how Ge substrates are treated.
We found that H2 annealing was quite effective for achieving the atomically flat surface of Ge substrates. In parallel with this effort, we recently found that H2annealing of Ge substrates could improve the peak electron mobility significantly, even though the peak electron mobility on as-received Ge substrates was poor. This fact indicates that there is definitely another origin of electron mobility degradation inside Ge bulk, because the peak electron mobility is not significantly affected by the surface roughness scattering. This fact indicates that electron mobility is not simply understood by considering the scattering mechanisms reported for Si MOSFETs. Here, we report the relationship between electron mobility and oxygen atom concentration in Ge substrate.
Furthermore, we discuss effects of oxygen atoms in Ge substrate on reverse-biased n+/p junction leakage current. The oxygen atoms in Ge substrates experimentally reduced the leakage current in n+/p junctions. This result is good news for Ge technology, but it is incompatible with high electron mobility in terms of achieving high performance MOSFETs. Then, we fabricated MOSFETs with selective areal profile of oxygen atoms along the channel and source/drain regions. This method has enabled us to achieve high electron mobility in n-channel Ge MOSFETs together with high Ion
/Ioff
ratio.
Although the junction leakage has been considered to be intrinsically poor in Ge due to a narrower energy band gap, this paper strongly suggests that Ge technology will be further improved for the best with the help of a rich heritage of Si technology.
The Improvement Magnet Plate on a Reticle Stage of Lithography Equipment through Analyzing Adhesive and Roughness of Plate
Authors: Yu Ik Hwan , Kim Gun Rae , Jung Hag Su , Bae Jae Sung 
Published: February 2020

Semiconductor lithography scanners are extremely complex equipment which is used to manufacture IC(Intergrated Circuit). Moore's law, which states that the computing power per chip doubles every one and a half to two years, has consistently held for four decades. [1] The exposure system in semiconductor has been rapidly developed based on the Moore's law. Most semiconductor manufacturers have been using ASML scanner for exposure on wafers. The reticle stage of ASML scanner exists over magnet plates. The electric currents are supplied to the coil of the inside magnet，the reticle stage can move forward and backward by Fleming's left hand rule. [3] The reticle stage is synchronized with wafer stage of movement. At that time, scan speed is very fast, reticle stage scan velocity is about 2.4m/sec, in addition acceleration reaches to 9G. So the conditions are very harsh to stage. However, with current technology, we cannot manufacture the whole mass of magnet as long as long stroke of reticle stage. (approximately 2.4m) So they manufacture it on plate by attaching 600mm pieces of magnet. Over time, the magnet plates attached to the main frame are getting weak. At the end of magnet which is the weakest point can be easily cracked because it is changing of flux density in magnet plate. We analyze bonding method between magnet and plate. In addition, we tested it on a different roughness for the plate. Through the change of the material and roughness, we could improve prevent the plate from cracking. In this paper, we propose how to protect broken magnet by changing the material of adhesive and roughness of plate. As a result, we can expect to increase stability in the magnet plate on a reticle stage by more than 10%.

[1] G. E. Moore, “Cramming more components onto integrated circuits,” Electron. Mag., vol. 38, no. 8, pp. 4–7, 1965.
[2] Hans Butler, “Position control in lithographic equipment”, IEEE Control Systems Magazine, October 2011
[3] Kenjō, Takashi, and Shigenobu Nagamori. Permanent-magnet and brushless DC motors. Vol. 18. Oxford University Press, USA, 1985.

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Electrografted P4VP as Dielectric in High Aspect Ratio TSV: Surface Preparation and Thermomechanical Consideration
Authors: Dequivre Thomas , Al Alam Elias , Plathier Julien , Ruediger Andreas , Brisard Gessie , Charlebois Serge 
Published: February 2020

A key to most 3D integration approaches is the deposition of the Through-Silicon-Via (TSV) dielectric layer. A TSV is traditionally electrically insulated from the silicon substrate by a thin SiO2 film. As TSV aspect ratio is getting higher, conformal SiO2 dielectric deposition is getting harder. Alchimer has proposed a high conformal organic (poly-4-vinylpyridine, P4VP) as dielectric. This polymer is electrografted through electrochemical reduction of diazonium salts in aquous media. Although the electrografting process is well described in the literature [1, 2], electrical and thermomechanical properties of such material grafted onto silicon structure remain incomplete. This information is mandatory in order to optimize 3D integrated processor’s layout.
Since electrografting mechanism is initiated from the surface [2], P4VP material properties and kinetic growth can vary with the surface preparation of the TSV. Results obtained on TSVs, with various surface preparations, insulated by electrografted P4VP suggest that the polymer is not only a good dielectric, but could allow a reduction of the Keep Out Zone (KOZ) size for a higher integration density. Furthermore, as P4VP is a viscoelastic material, its Young’s modulus is temperature dependent and dramatically drops down above its glass transition temperature. Such a material is particularly interesting to reduce stress as it can act as a buffer stress layer.We will present the study of electrical and thermomechanical properties of the electrografted P4VP dielectric realized on high aspect ratio TSV. We will discuss the impact of TSV surface preparation on the electrografting process and on the material properties of the P4VP grafted layer. Results will be compared to more conventional approaches based on a silicon oxide insulator. Acknowledgement
Université de Sherbrooke, Natural Sciences and Engeeniring Research Council of Canada (NSERC), Institut National de la Recherche Scientifique (INRS), Teledyne Dalsa and Alchimer are gratefully acknowledged for their help and their financial support.

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(Invited) Microstructural Modeling of Heterogeneous Nucleation and Growth of Lithium Electrodeposits
Authors: García R. Edwin 
Published: February 2020

Through numerical modeling and simulation, we explore the charge/discharge conditions that lead to the formation of lithium dendrites in rechargeable lithium-ion batteries. Firstly, by using high resolution X-ray tomography, a three-dimensional representation of a lithiated graphite anode microstructure from a commercial battery was used as input to simulate the local electrochemical behavior that will favor heterogeneous lithium nucleation. The analysis demonstrates that spatial variation in porosity, particle roughness and morphology significantly alter the local intercalation kinetics, state of charge and mechanical stability, and dendrite formation. Secondly, by using the phase field approach, we demonstrate the conditions that will enable an overpotential-controlled critical lithium electrodeposit to become energetically favorable and identify the regimes of dendrite nucleation, growth, and suppresion behavior.

Figure 1
Evaluation of Relationship Between Dynamic Structural Deformation and Output Performance in Lithium-Ion Battery By Numerical Simulation
Authors: Inoue Gen 
Published: February 2020

In order to improve the performance of Lithium ion secondary battery (LiB), it is very important to understanding the internal transport phenomena under high rate condition to increase power density. In my previous study, I focused on the actual porous electrode structure, and the Li ion and electron conductivity was evaluated by the effective conductive path with the actual reconstruction electrode structure [1], [2]. However, the effect of volume expansion of charge-discharge state is not been understood enough. In this study, I examined the new model with structure change based on the actual porous electrode structure, and the relationship between structural change and battery performance was considered. Actual Graphite anode and LiCoO2 cathode electrode structure were reconstructed by FIB-SEM, and the reaction and mass transfer in these reconstructed electrode structure and simulated separator structure were simulated by multi-block method [3] which is the method of coarse graining to keep the information of heterogeneous structure. Li concentration and potential distribution in active material (AM) and electrolyte (EL) were calculated with Butler-Volmer equation as the boundary condition of the interface between AM and EL. it was assumed that temperature is constant, the formation of SEI is ignored, binder phase inhibit ionic transfer. The discharge performance was calculated with 1M LiPF6－EC/DEC (1:1) and the condition reported previous research[4]. Figure 1 shows the cell structure, current density distribution and Li concentration distribution in AM. The current density near LCO collector became lower because of the lack of Li ion caused by binder migration. In addition, the simulation results were compared with experimental results which were obtained by coin cell with same electrode structure. These results were almost equal to each other. Furthermore, the effect of volume expansion was included in this previous model. Especially, the effect of electrolyte convection caused by the change of porosity was examined. Figure 2 shows the simulation results of the discharge-distribution with volume expansion. From this result, it was found that the effect of convention cannot be ignored in the case of high expansion volume ratio (more than e=2)
References
[1] G. Inoue et al., Proc. PRiME 2012, B6 #803 (2012)
[2] G. Inoue et al.,
J. Power Source
175, 145-158 (2008)
[3] G. Inoue et al., ECS Trans.,
25 (1) 1519-1527 (2009)
[4] G. Inoue et al., ECS 226th meeting, A5 #374 (2014)

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Reaction and Mass Transport Simulation of 3-Dimensional All-Solid-State Lithium-Ion Batteries for the Optimum Structural Design
Authors: Itoh Fumiya , Inoue Gen , Kawase Motoaki 
Published: February 2020

In order to increase energy density and enhance safety, all-solid-sate lithium-ion batteries have been developed as a storage battery for electric vehicle (EV). However, it is necessary to decrease a mass transfer resistance and a reaction resistance because its power density is too low to be applied for EV. In recent years, 3-dimensional (3D) electrode such as an interdigitated electrode is proposed, which can increase power density without losing high energy density [1, 2]. The purpose of this study is to simulate the electrochemical reaction and lithium-ion transport phenomena of 3D all-solid-state batteries for the optimum design of 3D structure which can fully charge within 5 minutes.
Based on the porous electrode theory, reaction and mass transport at the galvanostatic discharge were simulated [3, 4]. In this work, the solid-solid interface resistance and the volume change of active materials were neglected. The temperature distribution in the cell was presumed to be uniform. Assuming that active materials are nano-scale particles, lithium diffuses rapidly enough in an active material particle. Therefore, the lithium concentration distribution in the particles was also supposed to be uniform. Figure 1shows some examples of 2D and 3D structures for simulation. These structures are symmetry and the cell is the same size in all structures. In addition, all volume of cathode, solid electrolyte (SE) and anode layer is equal. LiCoO2 and graphite were employed as cathode and anode active materials, respectively. Each structure was simulated at a rate of 1-10C and an SE ionic conductivity of 1-0.01 S/m. And discharge properties of 2D and 3D structures were investigated.

Figure 2shows the galvanostatic discharge curve obtained from the simulation at a rate of 10C and an ionic conductivity of 1 S/m. There was no big difference between the discharge curves of Str.1-13 at a rate of 1C. However, discharge properties of some structures at 10C were degraded because a voltage drop occurred before depth of discharge reaches 1.0. As shown in Figure 2, Str.2 and Str.3 displayed high discharge property at 10C as well as at 1C. This result indicates that discharge property was improved by complicating 3D structures. Furthermore, a cell design parameter was proposed and investigated for the optimum structural design.
References
[1] R.W. Hart, H. White, B. Dunn, D. Rolison, Electrochem. Commun.
5 (2003), 120-123.
[2] Y. Suzuki, H. Munakata, K. Kajihara, K. Kanamura, Y. Sato, K. Yamamoto, T. Yoshida, ECS Transactions, 16 (26) (2009), 37-43.
[3] M. Doyle, T. F. Fuller, J. Newman, J. Electrochem. Soc., 140(1993), 1526-1533.
[4] G. M. Goldin, A. M. Colclasure, A. H. Wiedemann, R. J. Kee, Electrochimica Acta, 64 (2012), 118-129.

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Electrolyte Properties of Li4P2S6 -- Simulations and Comparison with Experiment
Authors: Holzwarth Natalie A. W. , Hood Zachary D. , Kirkham Melanie J. 
Published: February 2020

Structural and electrolyte properties of Li4P2S6 have been investigated with computer simulations and with a variety of experiments including X-ray and neutron diffraction, electrochemical measurements, and thermal response. Compared with other thiophosphate materials, Li4P2S6 is quite stable; maintaining the same crystal structure up to temperatures as high as 950 degrees C in vacuum and up to 280 degrees C in air. While its ionic conductivity is relatively small, its Arrhenius activation energy of 0.29 eV is similar to technologically viable electrolytes. Computer simulations provide insight into the causes and effects of disorder in this material and indicate that the mechanism of the ion conductivity is dominated by interstitial sites. Simulations of idealized interfaces of a Li4P2S6 electrolyte with a Li metal anode are also analyzed.

Acknowledgements:

The computational portion of this work was supported by NSF grant DMR-1105485. Z. D. Hood was supported by the Higher Education Research Experiences (HERE) program at Oak Ridge National Laboratory. The experimental portion of this work was primarily conducted at the Center for Nanophase Materials Sciences and ORNL’s Spallation Neutron Source , which are DOE Office of Science User Facilities. Cameron Kates, Shiba Adhikari, and Chengdu Liang also contributed to this project. Assistance from Jong Keum, Andrew Payzant, Gayatri Sahu, Hui Wang, Keerthi Senevirathne, Cynthia Day, and Abdessadek Lachgar are also gratefully acknowledged.
Mg Desolvation and Intercalation Mechanism at the Mo6S8 Chevrel Phase Surface
Authors: Wan Liwen , Perdue Brian Robert , Apblett Christopher A. , Prendergast David 
Published: February 2020

In recent years, there are strong interests to develop new divalent electrochemical systems that can potentially provide higher energy density compared with current Li-ion batteries, but with lowered cost and improved cycle stability. Mg-ion battery technology, first established in 2000 [Aurbach et al., Nature 407, 724 (2000)], proves the cyclability of such divalent battery cell. In this manuscript, we examine Mg-ion desolvation and intercalation process at the Chevrel phase Mo6S8 cathode surface using first-principles based methods. It is known that in chloride based electrolytes, Mg2+ is strongly coordinated by the counterion Cl- with a binding energy on the order of 3 eV. During cell discharge, this Mg-Cl bond is broken and Mg is intercalated into the cathode material. Our simulation indicates the broken of such strong ionic bond can only be possible if another electrophilic agent, such as Mo, exists on the cathode surface to attract Cl- away from Mg2+. Once Mg is intercalated, the Chevrel phase surface becomes chlorinated, i.e. all open Mo sites are attached with Cl-. Further simulations show that this chlorinated surface can continue to interact with incoming MgCl+ species and form various MgCly adsorbates. These surface adsorbates can then release neutral MgCl2 back into the electrolyte and reopen Mo sites to the electrolyte to permit continuous Mg intercalation. The newly release MgCl2 species will likely increase salt concentration near the cathode surface and initiate MgxCly oligomerization and precipitation, which are characterized by full-cell experiments.
Our results suggest that when designing new divalent battery systems, one should consider the compatibility issue between the electrolyte and the cathode material that has often been overlooked. For example, with the potential of increasing cell voltage, transition metal oxides, such as V2O5 and MoO3 are proposed as the Mg intercalation cathode. However, these layered oxide structures usually do not present open metal sites, but rather oxygen at their surfaces, which is less likely to attract any strongly coordinated counterions away from Mg2+ to assist its desolvation and intercalation. Therefore, such oxide cathodes usually require weakly coordinated anions to be used in the electrolyte, which may no longer be compatible with Mg metal as the anode material.
This work is supported as part of the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.
Synthesis of II-VI Semiconductors Thin Films By Ecald from Citric Buffer
Authors: Kowalik Remigiusz 
Published: February 2020

Electrochemical Atomic Layer Deposition (ECALD) was proposed by Stickney and coworkers[1] to obtain low-cost production of structurally well-ordered II-VI compound semiconductors, such as transition metal chalcogenides, on polycrystalline as well as on single-crystal electrodes. The method is based on the alternate underpotential deposition (UPD) of atomic layers of the elements that form the compound. Underpotential deposition is the well-known phenomenon whereby the potential necessary to deposit one element onto a second element occurs before that necessary to deposit the element on itself. The phenomenon is surface limited, so that the resulting deposit is generally limited to one atomic layer. Moreover, when the UPD is performed on a single crystal face the resulting deposit is epitaxial.
The free energy change involved in the compound formation is generally negative enough to produce the underpotential deposition of the metallic element on a layer of the previously deposited nonmetallic element, and vice versa. The number of cycles, which determines the thickness of the deposits, can be repeated as many times as desired to obtain deposits of practical importance. By limiting depositions to single atomic layers, no three dimensional growth is promoted and epitaxy should result.
Once the deposit is formed, the amount of the elements deposited is determined from the charge involved in their stripping. Such investigations always confirmed the stoichiometric ratio of the elements forming the compound.
The fundamental object to the method is the necessity of singling out the proper electrochemical conditions to be used, i.e. potentials, reactants, electrolytes and pH. Moreover, being the method based on surface phenomena, the electrochemical conditions are also dependent on the substrate used. Here, the first results of the electrodeposition of CdSe and ZnSe on polycrystalline gold from citric buffer are reported.
Acknowledgments
This work was supported by the Polish National Center of Science under grant 2011/01/D/ST5/05743.
1. Gregory, B.W. and J.L. Stickney, Electrochemical atomic layer epitaxy (ECALE). Journal of Electroanalytical Chemistry, 1991. 300(1-2): p. 543-561.
Nanostructured, Bimetallic, Noble Metal Powders Prepared By Atomic Layer Electroless Deposition for Applications in Sensing and Catalysis
Authors: Cappillino Patrick J , Sugar Joshua D , El Gabaly Farid , Cai Trevor , Liu Zhi , Stickney John Lewellen , Robinson David B. 
Published: February 2020

Bimetallic materials exhibit properties that are superior to their constituents in many applications. Examples include alkyne hydrogenation catalysts (selectivity), fuel cell cathodes (higher activity), formic acid oxidation catalysts (resistance to poisoning) and hydrogen storage materials (faster kinetics). A key to improving our understanding of these phenomena is preparation of these materials with nanoscale control of composition. Although recent efforts have focused on controlled synthesis of bimetallic particles, there remains a strong need for a synthetic strategy combining the properties of (i) scalability on high-surface-area substrates, (ii) uniform deposition and (iii) low-temperature processing conditions that preserve nanostructures.
Presented herein are details of an Atomic Layer Electroless Deposition (ALED) technique that meets these criteria. By exposing Pd powder to dilute hydrogen in nitrogen gas, sacrificial surface PdH is formed along with dilute interstitial hydride. Once the flow of reagent is terminated, addition of metal salts facilitates galvanic displacement of the hydride, and controlled deposition of an overlayer having sub-nanometer thickness. This process can be cycled to create mesoscale layers. The electroless nature of ALED and its ambient processing conditions, make it an excellent complement to existing strategies of noble metal ALD.
We will present high-resolution scanning electron microscopy demonstrating that conformal layers can be formed, and that the degree to which three-dimensional growth occurs is dependent upon deposition conditions. In addition, depth-profiles of bimetallic powders of varying adlayer thickness, generated using energy-resolved X-ray photoelectron spectroscopy, will be presented. We will also show evidence for fractional adlayer coverage based on the infrared spectra of adsorbed organic molecules. These data provide a proof of concept for using materials prepared by ALED as high-selectivity, high-dynamic-range sensors for various target molecules. Finally, we will demonstrate the ability of materials prepared in this manner to act as bi-functional catalysts.
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. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Support for JLS was in part provided by the National Science Foundation, Division of Materials Research, grant #1006747. The authors also thank Mark Homer for STEM sample preparation.

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