bluuebunny/crossref_metadata_2025 huggingface dataset:
In-Process Machining Process Monitoring Method Based on Impedance Model of Dielectric Coating Layer at Tool-Chip Interface
Authors: Chun Heebum , Kim Jungsub , Nam Jungsoo , Ju Songhyun , Lee ChaBum
Published: September 2022

In this study, we investigated a novel approach that enables the in-process machining process monitoring at the tool-chip interface (TCI) by utilizing the impedance characteristics of the dielectric coating layer of the cutting tool. This study first analyzes the Nyquist diagram that characterizes the impedance response of a few micrometer-thick dielectric layers coated on the surface of the cutting tool by using an impedance analyzer under various temperature conditions for establishing the relationship between the relative permittivity of the dielectric layer and temperature. Consequently, the impedance of the dielectric layer was subject to change according to given temperature conditions. Thus, under its temperature-dependent impedance characteristics, the machining processes could be in-situ tracked and analyzed by directly probing the localized TCI, the so-called cutting hot spot, during the machining. The current source was implemented with the machining system and the variations of impedance at TCI were monitored during the facing process. As a result, impedance responses were remarkably changed under various machining conditions. The impedance was further characterized under the varying depth of contact and the impedance was decreased as the depth of contact increased. Therefore, the preliminary study demonstrated that an electrical impedance model of the dielectric coating layer may be applied for an in-process machining process monitoring method to analyze and assess the phenomenon of the machining process at the local TCI region. This study is expected to potentially provide utilization in advanced manufacturing to improve final part quality and productivity.
Effects of Stimulus Conditions on Shape Memory Cycle Durability of 4D Printed Parts in Stereolithography Additive Manufacturing
Authors: Zhao Jing , Han Muyue , Li Lin , Tan Miao
Published: September 2022

4D printing has recently emerged as a new manufacturing paradigm by integrating shape memory materials with 3D printing technology. Distinctively, 4D printed structures exhibit dynamic shape changing capability over time in response to certain stimuli. The emerging shape memory property of 4D printed components has attracted increasing research attention due to its potential applications in soft-robotic, origami, and self-construction structures. Ensuring product durability is key to enhancing the technology diffusion of 4D printing as it significantly affects the product service life. In the current literature, durability issues in 4D printing have been largely overlooked and the relationships between external stimulus conditions and the thermo-mechanical cycle life of 4D printed parts remain unknown. To tackle this challenge, in this study, the design of experiments approach is adopted to comprehensively investigate the impacts of external stimulus conditions on the shape memory cycle life of the 4D printed thermo-responsive parts. The results suggest that increasing the operating temperature within the material-allowable temperature range would negatively affect the shape memory cycle times; meanwhile, varying the shape programming hold time also exhibits noticeable impacts on the durability of 4D printed parts. In addition, the extreme stimulus conditions with respect to the high temperature and prolonged shape programming time would worsen the shape memory cycle life.
Design and Fabrication of MRI-Compatible and Flexible Neural Microprobes for Deep Brain Stimulation and Neurological Treatment Applications
Authors: Wang Yi , Lee Sung-Ho , Shih Yen-Yu Ian , Lee Yuan-Shin
Published: September 2022

This paper presents a new design and fabrication method of flexible neural microprobes for deep brain stimulations (DBS) and neurological treatment applications. The developed new flexible microprobes are compatible with functional magnetic resonance imaging (fMRI) and can be used for neurological studies of brain functions under functional imaging such as fMRI for a long period of time. In this paper, the materials of the flexible neural microprobes are comprehensively selected to minimize the magnetic resonance imaging (MRI) artifacts, which limits many conventional feasible manufacturing processes to be used. Polyimide was adopted for the substrate of the neural microprobe, which has good biocompatibility and a relatively lower Young’s modulus. A 200 nm chromium reinforcement layer was embedded in the microprobe to attenuate its implantation stiffness while remaining flexible. Gold electroplating was employed to modify the electrode sites to improve the signal quality and sensitivity. The designed new neural microprobes were successfully fabricated at our NCSU Nanofabrication Facility (NNF) and bonded to a customized PCB. After the fabrication, the developed neural microprobes were characterized to validate their effectiveness. In vivo simultaneous DBS-fMRI experiments were conducted in surgery rooms on a rat’s deep brain targets, demonstrating the potential applications of our neural microprobe for neuroscience studies, medical diagnosis, and treatment applications. In vivo electrophysiology results show the effectiveness of our fabricated neural microprobes.
Electrical Resistance Metrology in Nanoparticle Sintering Simulations
Authors: Dibua Obehi , Foong Chee S. , Cullinan Michael
Published: September 2022

Microscale Selective Laser Sintering is an Additive Manufacturing process which involves the creation of parts using nanoparticles, precision substrate motion control, and an optical setup aimed at achieving sub-micron resolution on the printed parts. In order to drive the Microscale Selective Laser Sintering process towards this proposed goal, it is important to understand the kinetics of nanoparticle sintering to be able to make predictions of the properties that can be expected from the manufacturing process. To this end, Phase Field Modelling simulations have been built which model how nanoparticles sinter together when heated. In the past these simulations have yielded measurements such as the densification in the powder bed as a function of temperature and time, however it is extremely difficult to measure the density of parts built from the microscale Selective Laser Sintering system. Electrical resistance is a much more easily quantified property. As such, in order to fully validate these nanoparticle sintering simulations, it is necessary to measure the electrical resistance in the simulation bed and compare these resistance curves against experimentally derived electrical resistance measurements. This paper presents the approach used to extract electrical resistance data from the simulations as well as preliminary resistance results collated from this study.
On the design and analysis of near-term quantum network protocols using Markov decision processes
Authors: Khatri Sumeet
Published: September 2022

The quantum internet is one of the frontiers of quantum information science. It will revolutionize the way we communicate and do other tasks, and it will allow for tasks that are not possible using the current, classical internet. The backbone of a quantum internet is entanglement distributed globally in order to allow for such novel applications to be performed over long distances. Experimental progress is currently being made to realize quantum networks on a small scale, but much theoretical work is still needed in order to understand how best to distribute entanglement, especially with the limitations of near-term quantum technologies taken into account. This work provides an initial step toward this goal. In this work, we lay out a theory of near-term quantum networks based on Markov decision processes (MDPs), and we show that MDPs provide a precise and systematic mathematical framework to model protocols for near-term quantum networks that is agnostic to the specific implementation platform. We start by simplifying the MDP for elementary links introduced in prior work and by providing new results on policies for elementary links in the steady-state (infinite-time) limit. Then, we show how the elementary link MDP can be used to analyze a complete quantum network protocol. We then provide an extension of the MDP formalism to two elementary links. Here, as new results, we derive linear programing relaxations that allow us to obtain optimal steady-state policies with respect to the expected fidelity and waiting time of the end-to-end link.
Inherent tendency of
Synechococcus
and heterotrophic bacteria for mutualism on long-term coexistence despite environmental interference
Authors: Nair Shailesh , Zhang Zenghu , Li Hongmei , Zhao Hanshuang , Shen Hui , Kao Shuh-Ji , Jiao Nianzhi , Zhang Yongyu
Published: September 2022

Mutualism between
Synechococcus
and heterotrophic bacteria has been found to support their prolonged survival in nutrient-depleted conditions. However, environmental interference on the fate of their mutualism is not understood. Here, we show that exogenous nutrients disrupt their established mutualism. Once the exogenous nutrients were exhausted,
Synechococcus
and heterotrophic bacteria gradually reestablished their metabolic mutualism during 450 days of culture, which revived unhealthy
Synechococcus
cells. Using metagenomics, metatranscriptomics, and the
15
N tracer method, we reveal that the associated bacterial nitrogen fixation triggered the reestablishment of the mutualism and revival of
Synechococcus
health. During this process, bacterial community structure and functions underwent tremendous adjustments to achieve the driving effect, and a cogeneration of nitrogen, phosphorus, iron, and vitamin by the heterotrophic bacteria sustained
Synechococcus
’s prolonged healthy growth. Our findings suggest that
Synechococcus
and heterotrophic bacteria may have an inherent tendency toward mutualism despite environmental interference. This may exhibit their coevolutionary adaptations in nutrient-deficient environments.
T
regs
in visceral adipose tissue up-regulate circadian-clock expression to promote fitness and enforce a diurnal rhythm of lipolysis
Authors: Xiao Tianli , Langston P. Kent , Muñoz-Rojas Andrés R. , Jayewickreme Teshika , Lazar Mitchell A. , Benoist Christophe , Mathis Diane
Published: September 2022

Regulatory T cells (T
regs
) in nonlymphoid organs provide critical brakes on inflammation and regulate tissue homeostasis. Although so-called “tissue T
regs
” are phenotypically and functionally diverse, serving to optimize their performance and survival, up-regulation of pathways related to circadian rhythms is a feature they share. Yet the diurnal regulation of T
regs
and its consequences are controversial and poorly understood. Here, we profiled diurnal variations in visceral adipose tissue (VAT) and splenic T
regs
in the presence and absence of core-clock genes. VAT, but not splenic, T
regs
up-regulated their cell-intrinsic circadian program and exhibited diurnal variations in their activation and metabolic state. BMAL1 deficiency specifically in T
regs
led to constitutive activation and poor oxidative metabolism in VAT, but not splenic, T
regs
. Disruption of core-clock components resulted in loss of fitness: BMAL1-deficient VAT T
regs
were preferentially lost during competitive transfers and in heterozygous T
reg

Bmal1
Δ

females. After 16 weeks of high-fat diet feeding, VAT inflammation was increased in mice harboring BMAL1-deficient T
regs
, and the remaining cells lost the transcriptomic signature of bona fide VAT T
regs
. Unexpectedly, VAT T
regs
suppressed adipocyte lipolysis, and BMAL1 deficiency specifically in T
regs
abrogated the characteristic diurnal variation in adipose tissue lipolysis, resulting in enhanced suppression of lipolysis throughout the day. These findings argue for the importance of the cell-intrinsic clock program in optimizing VAT T
reg
function and fitness.
Plate tectonics, mixed heating convection, and the divergence of mantle and plume temperatures
Authors: Seales Johnny , Lenardic Adrian , Tomasini Julian Garrido
Published: September 2022

Petrological data indicate that upper mantle and mantle plume temperatures diverged 2.5 b.y. ago. This has been interpreted as plate tectonics initiating at 2.5 Ga, with Earth operating as a single-plate planet before that time. We took an Occam’s razor view and hypothesized that the continuous operation of plate tectonics can explain the divergence. We validated this hypothesis by comparing petrological data to results from mixed heating mantle convection models in a plate-tectonic mode of mantle cooling. The comparison shows that the data are consistent with plate tectonics operating throughout geologic history.
Supplemental Material: Metamorphic Core Complex Dichotomy in the North American Cordillera Explained by Buoyant Upwelling in Variably Thick Crust
Authors: Zuza Andrew V. , Cao Wenrong
Published: September 2022

 A synthesis of timing constraints for the North American Cordillera metamorphic core complexes, a brief discussion the Conjugate Shatsky Rise, details of zircon Hf compilation, and methods and results of numerical simulations.  
An Integrated Circuit Based, Single-Inductor-Dual-Output Buck LED Driver for Dimmable and Color Temperature Tunable Indoor Lighting Application
Authors: Bakshi Biswadeep Gupta
Published: September 2022

Tunability of correlated color temperature (CCT) and dimmability are the two major sought after features of functional solid-state lighting. This paper presents a low-cost, efficient, single-inductor-dual-output buck driver that facilitates CCT-control and dimming of a light emitting diode (LED) module composed of cool-white and warm-white chips. The proposed driver is designed based on two familiar integrated circuits (ICs), namely LM2596 and NE556. LM2596 serves as the main switching regulator and amplitude modulation (AM) controller whereas NE556 serves as the constant-frequency, dual-output pulse-width-modulation (PWM) controller. The exponential model of LED is exploited for improved estimation of the design parameters of the LED module and the driver circuit. The developed driver prototype is tested for its electrical, photometric, and colorimetric performances. The driver offers a full-load efficiency of about 90% for a 12-W test LED module. Under different operating modes, the LED system can produce warm, cool, or neutral white light and at the same time, the produced illuminance can be varied over a wide range. Moreover, the light flicker is imperceptible since the PWM frequency is set according to IEEE-1789 guideline.
ANALYSIS OF THE SOCIO-ECONOMIC EFFECT OF MICROCREDIT ON MICRO-ENTREPRENEURS USING THE SELF-REPORTED PERCEPTION METHOD AND RELATIONSHIPS WITH OTHERS
Authors: AYAYI AYI GAVRIEL , DOUT HAMITANDE
Published: September 2022

Microcredit offers an innovative response to non-traditional financing and development needs for marginalized individuals. Here, impact assessment is very useful in that it helps to determine whether or not the objectives set at the onset are achieved and what can be done to correct the impediments to achieve better results. The paper analyzes the socio-economic effect of microcredit through the novel dual approach of self-reported perception and relationships with others. The data were gathered in collaboration with the Fonds Mauricie in November, 2019. Apart from the improvement in the financial indicators of micro-enterprises, the results show that microcredit has enhanced micro-entrepreneurs’ living conditions and family situation at rates of 88 and 91 percent, respectively. Regarding morale, 88 percent of micro-entrepreneurs report feeling better and optimistic about the future, and 92 percent report better relationships with others. In particular, the socio-economic effect of microcredit is determined by a better family situation, better living conditions and better financial situation and business income. These results imply that microfinance institutions must extend their financing to all segments of the population, especially the most vulnerable people such as immigrants and indigenous peoples.
A Six-Year Clinical Profile of Distal Radius Fractures in a South Asian Population
Authors: ANIL Abhijith , ACHARYA Ashwath M. , BHAT Anil K.
Published: September 2022

Background: The description, types and management of distal radius fractures have not been evaluated for a South Asian population. The aim of this study was to describe the clinical profile of distal radius fractures in adults over a 6-year period.

Methods: The medical records of distal radius fracture patients, aged 18 years and above admitted between August 2014 and 2020 were assessed. Epidemiological profile, fracture classification, treatment and reasons for implant removal were assessed.

Results: A total of 1066 distal radius fractures in 1005 inpatients were identified. The mean age was 42.1 ± 15.3 years (50.2 years [male] & 39.7 years [female]). A total of 65.5% patients sustained high-energy injury. 38.6% (n = 411) of fractures were classified as extra-articular AO-23-A, 24.3% (n = 259) as partially intra-articular AO-23-B and 39% (n = 416) as intra-articular AO-23-C. The treatment was non-surgical for 20.9% and surgical for 79.1% of cases. Plate fixation was the most frequently used surgical method followed by percutaneous pinning and external fixation. The proportion of patients treated by each modality remained constant based on a year-wise analysis of data. A total of 56 patients underwent implant removal, most commonly at the request of the patient.

Conclusions: Our study is the longest study in a South Asian setting where the population is younger, with a male pre-ponderance, sustaining high-energy injury as compared to the literature. This can be attributed to our study population being inpatients only. As population-based fracture registry is not available in our country, hospital-based studies such as ours provide the best option to study fracture patterns, distribution and trends in treatment.

Level of Evidence: Level IV
An Uncommon Presentation of Constriction Band Syndrome: A Case Report and Review of Literature
Authors: KARMAKAR Shilpi , MISHRA Brijesh
Published: September 2022

One of the rarer manifestations of constriction band syndrome (CBS) is peripheral nerve palsy. We report a 6-year-old child presenting with motor deficits of the median, ulnar and radial nerves and atrophy of the biceps and brachialis atrophy due to CBS. We were unable to find any similar reports in the literature. He had a constriction ring at the upper arm that had undergone multiple z-plasty by another surgeon. On examination, he had medical research council (MRC) grade 1 elbow flexion, weak flexion of fingers and absent extension of fingers and wrist. We used a pedicled pectoralis major myocutaneous flap to restore elbow flexion and the patient achieved M4 flexion of the elbow.

Level of Evidence: Level V (Therapeutic)
Progresses in the Research of Oceanic Freak Waves: Mechanism, Modeling, and Forecasting
Authors: Ma Yuxiang , Zhang Jie , Chen Qunbin , Tai Bing , Dong Guohai , Xie Botao , Niu Xuyang
Published: September 2022

In the 1990s, oceanographers realized that the freak waves posed realistic threats to offshore and marine engineering. Since then, tremendous efforts from both academia and industry have been made to reveal the physics of freak waves as well as their effects on structures. Despite the need for a uniform and robust definition and the ongoing discussion of the dominant mechanism, significant advances have been achieved in understanding freak waves in various aspects. As an emerging explanation of freak wave formation, the nonequilibrium dynamics has received much attention, as it provides insights into nonlinear focusing under complex changing environmental conditions. The new techniques for the generation or reproduction of freak waves are of higher efficiency and accuracy in terms of enhancing maximum wave height and controlling the focusing position and time. Besides, sidestepping the complex physical mechanisms, the machine learning, as a data-driven technique, provides an alternative approach for the investigation of freak waves. Tracking these new developments is the target of this review paper, the limitation of the current works and future perspectives are also discussed.
Emerging Technologies for Advanced 3D Package Characterization to Enable the More-Than-Moore Era
Authors: Hartfield Cheryl , Harris Will , Gu Allen , Terada Masako , Viswanathan Vignesh , Jiao Longan , Rodgers Thomas
Published: September 2022

The line between packaging and silicon interconnect technology is blurring due to a reduction in package interconnect dimensions, which drives an increase in image resolution requirements. It is becoming more difficult to localize and image defects and structures throughout the packaging life cycle, from materials selection, through package and silicon design co-optimization, development, production, and field failure diagnostics. Characterization and failure analysis (FA) solutions must provide fast results for rapid development of packages meeting the required electrical, mechanical and reliability specifications with high yield and quality. Heterogeneous integration and complex packages containing multiple die drive new approaches to rapidly characterize structures, defects and processes. This paper presents new artificial intelligence (AI) developments in 3D X-ray microscopy (XRM) for non-destructive submicron-resolution imaging of packages. It also introduces the latest developments in focused ion beam (FIB) microscopes adapted with an integrated fs-laser for precise and fast analysis of deeply buried features in advanced packages.
Reliability of Complete Plasma Etched Ru/Cu Lines
Authors: Su Jia Quan , Kuo Yue
Published: September 2022

The reliability of oxygen plasma-etched ruthenium/copper thin film stacks was studied under constant-current density and constant-voltage stress conditions. The thin ruthenium served as an adhesion layer for copper. The lifetime of the ruthenium/copper line was determined from resistance-time measurements. The ruthenium/ copper line had a longer lifetime than the titanium tungsten/copper line. The line failure process started from voids formation followed by growth and merging, which could be correlated to the change of the surface topography, especially near the broken area. Ruthenium can be a promising barrier material for interconnect copper lines.
Versatile Germanium Photodiodes with 3dB Bandwidths from 110 GHz to 265 GHz
Authors: Peczek Anna , Lischke Stefan , Steckler Daniel , Morgan Jesse , Beling Andreas , Zimmermann Lars
Published: September 2022

We demonstrate waveguide coupled germanium fin p-i-n photodiode being on a par with state-of-the-art III-V devices. The intrinsic, undoped germanium regions of the photodiodes are sandwiched in between two complementary in situ-doped silicon regions, circumventing ion-implantation into Ge. By scaling the width of the germanium, different combinations of bandwidths and responsivities can be obtained. Optoelectrical 3-dB bandwidths reaching up to 265 GHz at (1550 nm) 1 mA photocurrent and 2 V reverse bias are shown for a device with ~100 nm narrow germanium fin. Certainly, broader germanium region will yield higher responsivities but on the expense of 3-dB bandwidths. Increase of the germanium width from 100 nm to 450 nm results in a change in internal responsivity from 0.3 A/W to 1 A/W at -2 V bias. The impact of high photocurrent on performance of our new photodiodes will be presented in this paper.
A Near-Infrared pin Photodetector of Strain-Enhanced Ge Layer Epitaxially Grown on a Bonded Si-on-Quartz Wafer
Authors: Kuzutani Mikiya , Furuya Satoki , Piedra Lorenzana Jose Alberto , Hizawa Takeshi , Ishikawa Yasuhiko
Published: September 2022

A strain-enhanced Ge layer is epitaxially grown on a bonded Si-on-quartz (SOQ) wafer and is applied to a near-infrared pin photodetector (PD) at a normal incidence. X-ray diffraction measurement reveals a tensile in-plane lattice strain of 0.33 ± 0.01% in Ge on SOQ, which is generated by the mismatch of the thermal expansion coefficients between the Ge layer and quartz substrate of SOQ. The strain is approximately two times higher than 0.14 ± 0.01% in Ge on an ordinary Si wafer. Resulting from a direct bandgap narrowing under the tensile strain, the fabricated pin PD of Ge on SOQ exhibits a responsivity enhanced in the C+L band (1.530 – 1.625 µm).
Low Temperature Selective Epitaxy of Group-IV Semiconductors for Nanoelectronics
Authors: Khazaka Rami , Marozas Brendan , Kim Wonjong , Givens Michael
Published: September 2022

We have evaluated low temperature epitaxy (LTE) of Phosphorous doped Si (Si:P) and Boron doped SiGe (SiGe:B) on Si(001) substrates. The benefit of LTE is very significant, enabling incorporation of high levels of active dopant for both p- and n-type layers. This translates into lower resistivity compared to layers grown at higher temperature. However, several challenges appear when epitaxy occurs at low temperature (e.g., <500ºC): (i) low growth rate; (ii) loss of selectivity and (iii) crystallinity degradation, particularly on non-(001) surfaces. To overcome these issues, careful selection of precursors and optimization of process conditions is required. In this work, we discuss layer properties obtained on blanket Si(001) wafers. We have also evaluated the most promising SiGe:B growth conditions on patterned nanosheet structures, where the layer was shown to be selective towards SiN and SiO2 and crystalline growth was realized on Si(110) nanosheet sidewalls. Finally, selective process layer uniformity and wafer-to-wafer reproducibility were assessed over twenty Si(001) wafers showing excellent layer uniformity and wafer-to-wafer repeatability.
Compact Modeling of Forward Operation Band-to-Band andTrap-Assisted Tunneling Currents in SiGe HBTs
Authors: Zhang Anni , Niu Guofu , Li Yiao , Scholten Andries
Published: September 2022

A physics-based compact model of band-to-band tunneling (BTBT) and trap-assisted tunneling (TAT) currents in forward bias conditions is presented. The model is demonstrated on SiGe HBTs with heavily doped emitter-base junctions.
High Quality Ge Growth on Si (111) and Si (110) by Using Reduced Pressure Chemical Vapor Deposition
Authors: Yamamoto Yuji , Wen Wei-Chen , Schubert Markus Andreas , Corley-Wiciak Cedic , Tillack Bernd
Published: September 2022

A method for high quality epitaxial growth of Ge on Si (111) and Si (110) is investigated by reduced pressure chemical vapor deposition. Two step Ge epitaxy (low temperature Ge seed and high temperature main Ge growth) with several cycles of annealing by interrupting the Ge growth (cyclic annealing) is performed. In the case of Ge seed layer growth below 350 °C for (111) and 400 °C for (110) orientation, huge surface roughening due to too high dislocation density is observed after the following annealing step. For both crystal orientations, a high crystallinity Ge seed layer is realized by combination of 450 °C growth with 800 °C annealing. Once the high-quality Ge seed layer is deposited, high crystal quality Ge can be grown at 600 °C on the seed layer for both crystal orientations. For the 5 µm thick Ge layer deposited with the cyclic annealing process at 800 °C, a Si diffusion length of ~400 nm from the interface, RMS roughness below 0.5 nm and threading dislocation density of 5×106 cm-2 are achieved for both (111) and (110) substrates.
Stress Relaxation in SGOI Structure Obtained by Condensation
Authors: Mallet Anne-Flore , Gourhant Olivier , Duluard Christophe , Berbezier Isabelle , Favre Luc
Published: September 2022

Years of work have been dedicated to the optimization of thickstrain-relaxed buffers. Thanks to the use of graded Ge content layersbeneath the constant composition layers on top, threadingdislocations densities around 105 cm-2 have been obtained. Recentlyan innovative phenomenon has been observed concerning SiGe-On-Insulator (SGOI) layer relaxation. We propose to use this approachto obtain fully relaxed SGOI layers without dislocations in industrialconditions on 300mm wafers. This new approach would enable usto fabricate relaxed SGOI layers which are uniform in composition.Such an innovation would be relevant for several applications suchas, for instance, the re-epitaxy of Si0.5Ge0.5 layers.
Stress Engineering in Germanium-Silicon Heterostructure Using Surface Activated Hot Bonding
Authors: Lomonaco Quentin , Abadie Karine , Morales Christophe , Michaud Laurent Gaëtan , Richy Jérôme , Moreau Stephane , Colonna Jean-Philippe , Fournel Frank
Published: September 2022

The manufacturing of heterostructures is interesting in many fields such as photonics, solar energy production and quantum technologies. This paper, dedicated to germanium on silicon heterostructure manufacturing and stress engineering, builds up on LETI and EVGroup’s hot bonding technology (1). The coefficients of thermal expansion (CTE) mismatch between germanium and silicon is used to induce some in-plane tensile stress in a thin germanium layer transferred by the Smart CutTM technique onto a silicon substrate. In this approach, a bulk germanium wafer is directly bonded on a bulk silicon wafer, using surface activated hot bonding (SAHB). Process integration advantages are the low defect density of bulk germanium and the tensile stress that can be tuned using the bonding temperature. According to X-Ray diffraction measurements, for a bonding performed at 250°C, the lattice parameter deformation reached +0.06%, resulting in a 82 MPa tensile stress in a 370 nm thick germanium layer.
(Digital Presentation) Epitaxially Grown of SiGe on Ge Microbridge and Observation of Strong Resonant Light Emission
Authors: Inoue Takahiro , Wagatsuma Youya , Ikegaya Reo , Odashima Ayaka , Nagao Masaki , Sawano Kentarou
Published: September 2022

We observe strong room-temperature photoluminescence from Ge microbridges formed on Ge-on-Si (110). The Si (110) substrate is employed to fabricate the bridge along [111] direction as uniaxial strain in the [111] direction is expected to be the most effective to bring direct transition. In this study, we grow Ge-on-Si with (110) orientation and fabricate MB along the [111] directions. Due to the low etching rate of the (111) plane, however, etching of the Si under the square-shaped pads is quite difficult. By contrast, we fabricate branch-like MB, where the underneath Si was fully etched owing to the various directions of the etching. As a result, we obtained very strong resonant light emission.
Study of Dopant Activation in Arsenic-Implanted Laser Annealed Si By Differential Hall Effect Metrology (DHEM)
Authors: Joshi Abhijeet , Tabata Toshiyuki , Roze Fabien , Basol Bulent M
Published: September 2022

Ultra-violet (UV) laser annealing (LA) is a promising technology that is being investigated for next-generation CMOS processing. UV-LA’s unique capability of activating dopants very near to the surface due to the very shallow penetration depth can be critical for achieving very low-contact resistivity materials and structures. Here we present a detailed analysis of the effects of UV-LA on very highly As-doped material. Physical and chemical data-sets (SIMS, XTEM and FFTM) are compared with the electrical depth profiles obtained using Differential Hall Effect Metrology (DHEM).
Evaluation of Strained Group IV Semiconductor Devices by Oil-Immersion Raman Spectroscopy
Authors: Yokogawa Ryo , Chen Chia-Tsong , Toprasertpong Kasidit , Takenaka Mitsuru , Takagi Shinichi , Ogura Atsushi
Published: September 2022

We investigated stress evaluation of strained group IV semiconductor devices by oil-immersion Raman spectroscopy. In the oil-immersion Raman spectroscopy the high-numerical-aperture lens gives evaluation of complicated stress states in strained group IV semiconductor devices. As an example of the stress evaluation, a clear stress relaxation of the extremely thin body germanium on insulator (ETB GOI) channels was observed. This behavior indicates that the uniaxial stress is applied into GOI channels by patterning narrow channel. We confirmed that the uniaxial stress is applied into GOI channels by narrow channel patterning at even in ETB GOI channels down to approximately 4 nm by oil-immersion Raman spectroscopy, and stress relaxion (quasi-uniaxial stress) in GOI channels and hole mobility enhancement have good correlation.
(Invited, Digital Presentation) Evaluation of Polycrystalline-Si1-XGex Thin-Film Transistors Grown Laterally on a Glass Substrate Using a Continuous-Wave Laser
Authors: Hara Akito , Sagawa Tatsuya , Kusunoki Kotaro , Kitahara Kuninori
Published: September 2022

This study aims to understand the performance of continuous-wave laser lateral crystallization (CLC) poly-Si1-xGex TFTs. The transfer characteristics of n-ch CLC poly-Si1-xGex TFTs revealed that the threshold voltages shifted in the positive direction compared with those of CLC poly-Si TFTs with increasing Ge concentration. The characteristics of CLC n-ch poly-Si1-xGex TFTs can be explained by the formation of acceptors. For p-ch TFTs, the transfer characteristics of CLC poly-Si1-xGex TFTs exhibited a larger Ioff than those of CLC poly-Si TFTs. The Ion/Ioff ratio is small for p-ch parallel CLC poly-Si1-xGex TFTs and is weakly dependent on the gate length. In contrast, p-ch perpendicular CLC poly-Si1-xGex TFTs exhibit large Ion/Ioff values for long gate lengths. The variation in the Ion/Ioff ratio of p-ch CLC poly-Si1-xGex TFTs according to the parallel or perpendicular and long or short gate length is explained by Ge segregation along the grain boundary, resulting in the formation of a high-concentration p-type conduction region along the grain boundary, which connects the SD regions.
(Invited) Ultrawide Bandgap Transistors for High Temperature and Radiation Hard Applications
Authors: Shur Michael
Published: September 2022

Ultra-wide bandgap semiconductors - boron nitride, diamond, gallium oxide, and AlN - have a potential for high-temperature and radiation hard applications. These materials have a high breakdown field and large atom displacement energy correlated with a higher radiation hardness. Some of these materials, especially diamond, have a high thermal conductivity supporting a better heat handling capability, high low field mobility, and a high saturation velocity (for example, boron nitride) enabling a higher operating frequency, better microwave devices, and supporting operation in the 300 GHz band and above.
Analysis Method of Oxygen Permeation Resistance of Ionomer in Cathode Catalyst Layer in PEFC
Authors: Ogawa Hikaru , Kageyama Miho , Gyoten Hisaaki , Kawase Motoaki
Published: September 2022

For oxygen to reach platinum surface and react with protons, oxygen has to permeate through ionomer which is ion conductive polymer on the platinum surface. The oxygen permeation resistance of ionomer lowers the current density. In order to investigate governing factors of oxygen reduction reaction (ORR) rate, the oxygen permeation resistance should be analyzed. In this study, instead of commercial supported catalyst, a platinum slits catalyst was prepared by coating the platinum slabs with ionomer and ORR rate was measured. In order to determine the oxygen permeance, a dimensionless cathode isothermal one-dimensional model was applied. Although we had reported that the effectiveness factor of cathode catalyst layer (CCL) was a function of 4 dimensionless moduli derived from mass balance, new dimensionless moduli to quantitatively evaluate the oxygen permeance were introduced. Oxygen permeance at the temperature of 80 °C and inlet relative humidity (RH) of 0.76 was determined.
Preparation of Nanocrystalline Nb-Doped SnO2 on Mesoporous Carbon for PEFC Electrocatalysts
Authors: Inoue Yusuke , Yasutake Masahiro , Noda Zhiyun , Lyth Stephen Matthew , Nishihara Masamichi , Hayashi Akari , Matsuda Junko , Sasaki Kazunari
Published: September 2022

Platinum-based nanoparticles decorated on carbon supports (Pt/C) are widely used as electrocatalysts in polymer electrolyte fuel cells (PEFCs). Meanwhile, SnO2 is more stable than carbon at high potentials in cathodic environments. Highly durable Pt/SnO2/C electrocatalysts have therefore previously been developed using carbon nanomaterials as an electron-conducting backbone and SnO2 as a stable support layer for highly dispersed platinum nanoparticles. Here, we report on the development of Pt/SnO2/C electrocatalysts based on mesoporous carbon (MC) scaffolds. The electron conduction pathway through SnO2 was minimized by reducing the SnO2 loading. The use of Pt/SnO2/MC electrocatalysts resulted in high activity towards the oxygen reduction reaction (ORR) as well as excellent start-stop voltage cycling durability in half-cell conditions.
(Invited) Some Aspects of Electrode Kinetics and Electrolyte Stability in Vanadium Flow Batteries
Authors: Buckley D. Noel , Bourke Andrea , Oboroceanu Daniela , Lenihan Catherine , Al Hajji Safi Maria , Quill Nathan , Miller Mallory A. , Savinell Robert F. , Wainright Jesse S. , Sasikumar S P Varsha , Rybalchenko Maria , Amini Pupak , Lynch Robert P.
Published: September 2022

The electrochemical kinetics of the VII/VIII redox reaction on carbon electrodes is enhanced by anodic treatment of the electrode and inhibited by cathodic treatment. Contrastingly, the kinetics of the VIV/VV redox reaction is inhibited by anodic treatment of the electrode and enhanced by cathodic treatment. The observed effects are attributed to oxygen-containing species on the surface of carbon electrodes and it is likely that enhancement of both VII/VIII and VIV/VV occurs on the same (meso) state of the electrode. Oxidation of this active meso state leads to inhibition of VIV/VV while reduction of the active meso state leads to inhibition of VII/VIII.We have investigated the thermal stability of VFB catholytes using a standard methodology. The induction time for precipitation of V2O5 decreases exponentially with increasing temperature or VV concentration but increases exponentially with increasing sulphate concentration. Arrhenius plots show two linear regimes, at 45–70 °C and 30–45 °C, respectively. We model this behavior to estimate acceleration factors for testing of electrolyte stability over a range of test and use temperatures. Group V additives (phosphate and arsenate) are effective for improving the thermal stability of VFB catholytes.
Comparison of Operating Atmosphere Impact on La0.7Sr0.3V3.86-⸹ (LSV) Intermediate-Temperature Solid Oxide Fuel Cell Sulfur Tolerance Explored Through Experimental and Modeling Characterization Over Time
Authors: Burye Theodore , Sebastian Talia
Published: September 2022

Solid Oxide Fuel Cells (SOFCs) have the potential to provide clean, secure, and highly efficient sustainable energy for the U.S. Army. SOFCs can use many different reformed hydrocarbon fuels to obtain hydrogen for power generation, which include externally reformed JP-8, or can directly feed alternative fuels scavenged in theater. One long-term problem, specific for the U.S. Army, is sulfur performance degradation, common in most fuel options. JP-8 is not commonly desulfurized, and any scavenged fuel could be contaminated with sulfur. One solution to this problem could be the anode catalyst material, La0.7Sr0.3VO3.86-⸹ (LSV), which has previously demonstrated significant sulfur tolerance at temperatures greater than 700°C. This study further investigates LSVs sulfur tolerance at intermediate temperatures (400-700°C) in hydrogen and methane atmospheres up to 100 hours, where it was observed to be up to 278-287x more tolerant than Ni-YSZ (700°C), believed to be due to electronic/ionic changes occurring during exposure.
Synthesis of Yttrium Doped Barium Zirconate/Cerate Electrolyte Materials and Densification Using Conventional and Cold-Sintering Processes
Authors: Castellani Pablo , Nicollet Clement , Quarez Eric , Joubert Olivier , Le Gal La Salle Annie
Published: September 2022

Compared to high temperature solid oxide electrolysis cell, usually based on Yttrium stabilized Zirconia electrolytes, intermediate temperature proton conducting electrolysis cell, allows the production of water free hydrogen and a better chemical stability. Proton conducting perovskite materials, such as Barium Indates, Zirconates or Cerates are nearly commercial electrolytes for such devices. At intermediate temperature and under humid atmosphere, hydration process allows diffusion of protonic charges. Such electrolyte material combines a low thermal expansion coefficient and a high protonic conductivity. and The Zirconium rich material BaZr0.7Ce0.2Y0.1O3-δ that shows a conductivity around 10-2 S.cm-1 at 500°C will be compared to the Cerium rich BaZr0.3Ce0.6Y0.1O3-δ material that shows conductivities around 10-4 S.cm-1 at the same temperature.
The Transition (vs ΔpKa) from Triple Ions to Free Cations in Poor Protic Ionic Liquids Made from Weak Acids
Authors: Rana Smit S. , East Allan L. L.
Published: September 2022

In mixtures of amines with carboxylic acids, the limited ionicity at 1:1 stoichiometric mixtures is due to insufficient ionization or ion pairing in low-dielectric environments. Higher conductivities have historically been seen at roughly 4:1 acid/base mixing ratios, where simulations have revealed large (and thus more stable) ions: homoassociated anions (AH)(AH)(A−)(HA)(HA) and cationic triple ions (BH+)(AH)(A−)(HA)(HB+). Recent work in understanding the Gibbs energies for degree-of-ionization equilibria hints that there may be an onset, for systems with an acid-base pKa difference increasing towards 10, for the formation of free (unpaired) protonate-amine cations BH+. The transition with increasing ΔpKa is explored in this work, to aid in the prediction of ionicity and conductivity of protic ionic liquids.
(Digital Presentation) Influence of Pulse Electrolytic Conditions on Deposition Morphology of Electrolytic Aluminum Foil Using Chloroaluminate Ionic Liquids
Authors: Ui Koichi , Kobayashi Satoshi , Kono Makoto , Takeguchi Tatsuya , Tsuda Tetsuya , Ueda Mikito , Nunomura Junji , Honkawa Yukio , Oya Yoshiyuki , Kojima Yoichi
Published: September 2022

We have investigated the influence of additive agent on the deposition morphology of the electrolytic Al foils using the AlCl3–1-ethyl-3-methylimidazolium chloride (EMIC) (molar ratio 2 : 1) bath. The electrolytic Al foils were prepared by the pulse electrolysis. The morphology and the surface roughness of the electrolytic Al foils were characterized by FE-SEM, AFM, and XRD. The surface roughness and the crystallite size of the electrolytic Al foils were decreased by increasing the pulse frequency and the addition of 1,10-phenanthroline (OP). It was found that the OP addition had more greatly influence on the surface roughness of the electrolytic Al foil than the pulse frequency.
Physical and Electrochemical Analysis of Novel Boronium Cation-Based Ionic Liquids
Authors: Stachurski Christopher D. , Davis James H. , Cosby James , Larm Nathaniel E. , Durkin David P. , Trulove Paul C.
Published: September 2022

This work investigates a series of novel boronium-bistriflimide [TFSI-] ionic liquids using electrochemical and physical characterization techniques such as cyclic voltammetry, broadband dielectric spectroscopy, shear rheology, and thermogravimetric analysis. Systematic variations in boronium cation structure were employed to help identify the structural motifs that lead to optimal electrochemical and physical properties. The best performing boronium-based ionic liquids were then tested for initial lithium stability to further probe their potential for use in battery applications.
Electrochemical Deposition of Co-Mn Alloys Using CoCl2 - Mn(TfO)2 - bmimtfo Ionic Liquid Electrolytes
Authors: Li Min , Reddy Ramana G
Published: September 2022

Electrochemical deposition of Cobalt -Mnganese alloys was studied using CoCl2 - Mn(TfO)2 - BMIMTfO ionic liquid electrolytes. Constant potential electrolysis experiments were performed for different applied potentials at 363K in an Ar atmosphere for 2 h. The cyclic voltammograms (CV) for BMIMTfO, CoCl2 – BMIMTfO, Mn(TfO)2 - BMIMTfO and CoCl2 - Mn(TfO)2 - BMIMTfO systems were studied. The measured electrochemical window of neat BMIMTfO is 4.1V. Pure cobalt was produced by the reduction of CoCl2 in the CoCl2 – BMIMTfO system but no reduction of Mn(TfO)2 to Mn in the Mn(TfO)2 - BMIMTfO system was observed. The co-deposition of Co-Mn alloy in the CoCl2 - Mn(TfO)2 - BMIMTfO system was obtained. The SEM-EDS was used to determine the chemical composition of the alloy. The amount of Mn in Co-Mn alloy increased with increase in the applied cathode potential. The amount of Mn in Co-Mn alloy increases from 9.86 to 29.6 wt% with increasing the applied cathodic potential from –1.2 to –1.5 V respectively. The results showed that the Mn can be co-deposited with Co to form high grade Co-Mn alloy.
Lithium Difluoro(dioxalato) Phosphate as an Electrolyte Additive for NMC811/Graphite Li-ion Pouch Cells
Authors: Song Wentao , Gauthier Roby , Taskovic Tina , Ouyang Dongxu , Ingham Harrison A. , Eldesoky Ahmed , Azam Saad M. , Zsoldos Eniko S. , Deng Zhe , Heino Dylan H. , Geng Chenxi , Sidebottom Rowan , Dahn J. R.
Published: September 2022

Lithium difluoro(dioxalato)phosphate (LiDFDOP) has been systemically studied as an electrolyte additive singly and in combination with co-additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) in LiNi0.8Mn0.1Co0.1O2 (NMC811)/artificial graphite (AG) pouch cells. Long-term cycling tests at room and elevated temperatures (20 °C, 40 °C, and 55 °C) with different upper cutoff voltages (4.06 V and 4.20 V) were performed. These results were combined with ultra-high precision coulometry (UHPC), ex-situ gas measurements, and automatic cell storage tests to reveal multiple aspects of cell performance. A density functional theory (DFT) calculation has also been performed and compared to formation data to reveal the mechanistic aspects of LiDFDOP reduction. Radar plots and a figure-of-merit (FOM) approach were further utilized to summarize results and rank additive and additive combination performance for the NMC811/AG cells. This work highlights an effective additive and suitable co-additives for use in NMC811/graphite cells and gives important insights for future electrolyte additive studies.
Kinetic Monte Carlo Simulation Studies of the Shape of Islands on Close-Packed Surfaces
Authors: Sun G. S. , Jónsson H.
Published: September 2022

Kinetic Monte Carlo simulations are used to study processes that affect the shape of islands during growth of close-packed surfaces. The difference in adatom binding energy at the two types of edges and the relative height of diffusion barriers together with the incident flux and temperature determine which of the two types of edges dominates. This in turn affects strongly whether the crystal grows layer-by-layer or forms three-dimensional islands. Several features of the energy landscape that affect the island shape are illustrated. An unexpected edge nucleation effect involving addimer formation near a corner where edges meet can strongly affect the shape of small islands especially at low flux. Since the barrier for an adatom to exit a corner site to an edge site is lowered by such dimer formation, the overall activation energy for transport from an edge with low diffusion barrier to an edge with high diffusion barrier is reduced. As a result, small islands mainly have edges for which the diffusion barrier is lower. However, for large islands, the adatom is more likely to find a kink on the edge that has smaller diffusion barrier so large islands mainly has edges where the diffusion barrier is higher.