bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leveraging Contact Effects for Field-Effect Transistor Technologies with Reduced Complexity and Superior Current Uniformity
Authors: Sporea R. A. , Georgakopoulos S. , Xu X. , Guo X. , Shkunov M. , Shannon J. M. , Silva S. R. P. 
Published: December 2013

ABSTRACTIn order to achieve high performance, the design of devices for large-area electronics needs to be optimized despite material or fabrication shortcomings. In numerous emerging technologies thin-film transistor (TFT) performance is hindered by contact effects. Here, we show that contact effects can be used constructively to create devices with performance characteristics unachievable by conventional transistor designs. Source-gated transistors (SGTs) are not designed with increasing transistor speed, mobility or sub-threshold slope in mind, but rather with improving certain aspects critical for real-world large area electronics such as stability, uniformity, power efficiency and gain. SGTs can achieve considerably lower saturation voltage and power dissipation compared to conventional devices driven at the same current; higher output impedance for over two orders of magnitude higher intrinsic gain; improved bias stress stability in amorphous materials; higher resilience to processing variations; current virtually independent of source-drain gap, source-gate overlap and semiconductor thickness variations. Applications such as amplifiers and drivers for sensors and actuators, low cost large area analog or digital circuits could greatly benefit from incorporating the SGT architecture.
Simulation of Millisecond Laser Anneal on SOI: A Study of Dopant Activation and Mobility and its Application to Scaled FinFET Thermal Processing
Authors: Michalak Tyler J , Borst Chris , Franca Dan , Herman Josh , Rodgers Martin 
Published: December 2013

ABSTRACTThis work investigates scanning laser annealing used for ultra-shallow junction (USJ) activation. We investigate the laser system via simulation to determine the peak temperature achieved in the active area during processing. We employed the Sentaurus TCAD software by Synopsys to perform a 2D simulation of a laser scans across the active area of the device, solving the heat equation in both time and space. An absorber layer is deposited on the wafer surface to enhance the absorption of incident energy and reduce SOI reflectivity. An effective absorption coefficient of α=8000cm-1 was calculated for the absorber layer, calibrated with the experimental laser intensity. This absorption coefficient correctly predicts the silicon temperature as a function of power with any arbitrarily defined scan speed. To investigate the role of dopant activation, an SOI wafer was implanted with arsenic 25 keV, dose 3e15 /1.5e15 cm-2 and laser annealed in areas of target temperatures ranging from 850-1300°C. The sheet resistance was measured using 4-point probe showing sheet resistance improvement with increasing laser temperature. The extracted temperature cycle from the 2D heat simulation was used as an equivalent millisecond RTA in a full 3D process simulation to study dopant distribution and activation using Sentaurus Process Kinetic Monte Carlo (KMC), considering the effect of dopants, dopant clusters, and point defects. The results of this simulation demonstrate deactivation of arsenic above 1050°C, which is inconsistent with Hall measurements that suggest increasing laser temperature will increase mobility and activation. The results are analyzed versus the expected trends and suggest future improvements needed to the KMC model or the laser temperature profiles in order to describe activation kinetics in millisecond anneals within SOI.
Exposure Light Wavelength Effects on Charge Trapping and Detrapping of nc-MoOx Embedded ZrHfO High-k Stack
Authors: Liu Xi , Kuo Yue , Yuan Tao 
Published: December 2013

ABSTRACTThe influence of the red and green LED light exposure on the memory function of the nanocrystalline MoOx embedded ZrHfO high-k gate dielectric has been investigated. Since the performance of the device is mainly dependent on the hole trapping and detrapping mechanisms, the light exposure affects the hole generation, transfer, and storage to and in the dielectric structure. Both the charge storage capacity and the leakage current were increased from the light exposure. The Coulomb blockade phenomenon in the leakage current density vs. gate voltage curve disappears under the light exposure condition. The light exposure effect is potentially important for practical application of the device.
A 3D Soft-EHL Model for Simulating Feature-scale Defects in Advanced Node ICs
Authors: Sierra-Suarez Jonatan A. , Srivastava Gagan , Higgs C. Fred 
Published: December 2013

ABSTRACTA new multiphysics, multiscale framework is presented which is capable of capturing and predicting both wafer-scale and feature-scale defects. Through physics-based modeling, the empirical wear/Preston coefficient often found in popular feature scale models has been eliminated. Simulation results show the topography evolution of an actual metal 1 layout between two dies located in different positions on a wafer during the CMP process.
Low-Contact-Resistance Contacts to Graphene via Metal-Mediated Etching
Authors: Leong Wei Sun , Thong John T.L. 
Published: December 2013

ABSTRACTThe theoretically-predicted enhancement of metal-graphene contacts using the “end-contacted” configuration is studied. Graphene edges at the source/drain regions are created via a CMOS process compatible metal-assisted etching technique. The on-resistance of a graphene device with cobalt-etched-graphene contacts shows 6 times improvement compared to pristine graphene device. Apart from that, four-point contacted graphene devices with nickel-etched-graphene contacts were fabricated and tested under ambient conditions. The proposed graphene devices exhibit contact resistance as low as 14 Ωμm, with an average of 90 Ωμm. Thus, forming metal-etched-graphene contacts is a promising method to obtain low-contact resistance metal contacts to graphene.
Atomic Model of CdSe QDs Containing Density Waves as Derived from PDF Analysis
Authors: Palosz B. , Palosz W. , Wijewarnasuriya P. , Gierlotka S. , Skrobas K. , Stelmakh S. 
Published: December 2013

ABSTRACTUsing a new methodology of elaboration of PDF data (G(r) function), which is based on the analysis of individual inter-atomic distances (ri), a function describing differences between average inter-atomic distances in CdSe nanograins derived experimentally and those in the parent bulk crystal was determined. Based on that methodology a unique atomic architecture of CdSe QDs is proposed. The results show that a good knowledge about the grain surface of nanocrystals alone may be insufficient for understanding the nanomaterials properties, and that the real atomic structure of the interior of nanograins is of importance as well.
A New Solution to the Ni-fill issue for Silicide-last Process
Authors: Mao Shu J. , Zhao Li C. , Luo Jun. , Yan Jiang. 
Published: December 2013

ABSTRACTMetal Nickel(Ni) fill becomes the challeng in integrating silicide-last process into CMOS advanced technology with further contact size scaling. In this work, the specific contact resistivity (ρc) of cold titanium(Ti)/Si was investigated by the cross-bridge Kelvin resistor(CBKR) method and compared with that of Ni(Pt)Si/Si. The cold Ti/n+-Si showed comparable contact resistance(ρc∼3x10-8Ω·cm2) to Ni(Pt)Si/ n+-Si, while a larger ρc(7.5x10-1Ω·cm2) for cold Ti formed on B+ doped Si substrates. The cold Ti/Si interface was also discussed. Our results furnish a fresh perspective on the solutions to the metal fill challeng for silicide-last process.
Al CMP for Low Resistance Gate Fill for 20nm and Beyond Replacement Metal Gate
Authors: Economikos Laertis , Zhang Xing , Hwang Haigou , Kwon Unoh , Wong Keith , Escarabajal Yann , Lagudu Uma R. K. , Chockalingam Ashwin , Babu S.V. 
Published: December 2013

ABSTRACTAluminum (Al) gate fill has been implemented in Replacement Metal Gate (RMG) due to its low resistivity. Titanium (Ti) has been widely used as wetting layer for Al to fill the gates. For low resistance gate fill in structures with small feature size and high aspect ratio, Ti-Al metal fill becomes increasingly more challenging as we move from 20nm into 14nm FinFET and 3D type structures.Cobalt (Co) is a good wetting film for Al with better fill performance and lower resistance than Ti-Al based process. However, due to the difference in corrosion potential between Al and Co, Chemical Mechanical Planarization (CMP) creates pitting type defects on Al-Co film that increases resistance variability across pattern density. CMP induced corrosion is separated in two parts; first is the static Co corrosion happened in the acidic chemical environment in the Al slurry. Second is the galvanic corrosion from Co-Al metal boundary due to high metal electrical potential. Static corrosion can be resolved by adding a Co corrosion inhibitor in the slurry formulation1. Galvanic corrosion can be minimized by controlling Co thickness deposition and formation of complete intermetallic phase. By controlling the removal rate with respect to corrosion rate we were able to suppress corrosion significantly.We looked into compositions where the corrosion potential (Ecorr) gap between Al and Co is reduced to ≤10mV leading to reduced galvanic currents. Stabilization of the corrosion currents in both Al and Co was observed using potentiodynamic scans. The effect of pH, several oxidizers and additives on the open circuit potentials (Eoc) of Al and Co was investigated and it was found that solutions of KMnO4, saccharides and sulfonate group containing compounds help reduce the Ecorr gap in between Al and Co to ∼10 mV.Controlling the Al gate height across pattern densities and gate lengths to within few nm is another challenge for Al CMP. The industry widely used approach is to clear all Al using a slurry with high selectivity to dielectric, followed by a CMP step using a non-selective Al-to-oxide slurry. Both polishing steps need to be optimized in parallel in order to remove the incoming spacer SiN divot, minimize Al loss on gates with high pattern density or long gate length, minimize oxide loss on large open areas while maintaining low defectivity.In this paper we are presenting an innovate Al CMP process that demonstrated low gate resistance with tight distribution up to 80% pattern density. This work has been supported by the independent Bulk CMOS and SOI technology development projects at the IBM Microelectronics Division Semiconductor Research & Development Center, Hopewell Junction, NY 12533.
Modeling of “Pad-in-a-Bottle”: A Novel Planarization Process Using Suspended Polymer Beads
Authors: Fan Wei , Johnson Joy , Boning Duane S. 
Published: December 2013

ABSTRACTThe “pad-in-a-bottle” (PIB) approach to planarization is a non-traditional chemical mechanical polishing (CMP) process in which slurry containing polymer beads is used. The approach is hypothesized to be able to perform polishing by mixing polymer beads with similar chemical and mechanical properties as pad asperities into the slurry to provide force application and polishing contacts, so that a traditional CMP pad is not needed. Pad-in-a-bottle could provide predictable and controllable mechanical contacts through bead size control, which could substantially reduce process variability. Pad-in-a-bottle also has the potential to reduce the CMP consumable cost. In this work, we propose a physical model to understand the behavior of the pad-in-a-bottle approach and estimate the relationship of applied pressure and material removal rate in this variant of CMP. Two specific cases of polymer bead formation are considered in our modeling work, bead packing and bead stacking. Model prediction shows that the two bead formation cases generate distinctly different polishing mechanisms: material removal is applied pressure driven in bead packing, but contact event driven in bead stacking. The physical model suggests that in future experiments or applications of pad-in-a-bottle, a polymer bead size distribution or shape variation may be needed to achieve efficient material removal.
Characterization of chemically modified thin films for optimization of metal CMP applications
Authors: Basim G. Bahar , Karagoz Ayse , Ozdemir Zeynep 
Published: December 2013

ABSTRACTMetal CMP applications necessitate the formation of a protective oxide film in the presence of surface active agents, oxidizers, pH regulators and other chemicals to achieve global planarization. Formation and mechanical properties of the chemically modified metal oxide thin films in CMP determine the stresses develop at the interfaces delineating the stability and protective nature of the chemically altered films on the surface of the metal wafer. The balance between the stresses built in the film structure versus the mechanical actions provided during the process can be used to optimize the process variables and furthermore help define new planarization techniques for the next generation microelectronic device manufacturing. In this study, the preliminary studies were concentrated on the very well established tungsten CMP applications and furthermore, titanium CMP applications were presented as a part of surface nano-structuring methodology for biomedical applications by stressing the synergistic effect of protective metal oxide film of titanium in this advanced application.
Development of intelligent pad and application to analysis of pressure distribution on polishing pad in CMP process
Authors: Kinoshita Masaharu , Park Jaehong , Jeong Haedo 
Published: December 2013

ABSTRACTMost of polishing conditions are not consistent during the polishing process such as pressure, velocity, temperature, pad surface asperity and slurry flow which determine the CMP performance. Traditionally, these parameters are detected by various monitoring methods on CMP polisher. This study introduces a new concept of intelligent pad system with multiple sensors and peripheral devices such as memory, CPU, battery, transmitter and so on. The main functions of the intelligent pad are sensing the change of major parameters and data processing in real-time during the polishing process. The developed intelligent pad has nine points of embedded pressure sensor and makes data processing, saving, and transmitting in real-time. Experimentally, the intelligent pad system was evaluated to understand carrier behavior and pressure distribution. Finally, the analysis of pressure distribution using the intelligent pad turned out a useful method to understand the polishing head behavior and the polishing profile.
Association of Access to Publicly Funded Family Planning Services With Adolescent Birthrates in California Counties
Authors: Chabot Marina J. , Navarro Sandy , Swann Diane , Darney Philip , Thiel de Bocanegra Heike 
Published: December 2013

Objectives. We examined the association of adolescent birthrates (ABRs) with access to and receipt of publicly funded family planning services in California counties provided through 2 state programs: Medi-Cal, California’s Medicaid program, and the Family Planning, Access, Care, and Treatment (Family PACT) program. Methods. Our key data sources included the California Health Interview Survey and California Women’s Health Survey, Medi-Cal and Family PACT claims data, and the Birth Statistical Master File. We constructed a linear regression analysis measuring the relationship of access to and receipt of family planning services with ABRs when controlling for counties’ select covariates. Results. The regression analysis indicated that a higher access rate to Family PACT in a county was associated with a lower ABR (B = −0.19; P < .01) when controlling for unemployment rate, percentage of foreign-born adolescents, and percentage of adult low-income births. Conclusions. Efforts to reduce ABRs, specifically in counties that had persistently high rates are critical to achieving a healthy future for the state and the nation. Family PACT played a crucial role in helping adolescents avoid unintended and early childbearing.
Effect of Maternal–Child Home Visitation on Pregnancy Spacing for First-Time Latina Mothers
Authors: Yun Katherine , Chesnokova Arina , Matone Meredith , Luan Xianqun , Localio A. Russell , Rubin David M. 
Published: December 2013

Objectives. We examined the impact of a maternal–child home visitation program on birth spacing for first-time Latina mothers, focusing on adolescents and women who identified as Mexican or Puerto Rican.Methods. This was a retrospective cohort study. One thousand Latina women enrolled in the Pennsylvania Nurse–Family Partnership between January 1, 2003, and December 31, 2007, were matched to nonenrolled Latina women using propensity scores. The primary outcome was the time to second pregnancy that resulted in a live birth (interpregnancy interval). Proportional hazards models and bootstrap methods compared the time to event.Results. Home visitation was associated with a small decrease in the risk of a short interpregnancy interval (≤ 18 months) among Latina women (hazards ratio [HR] = 0.86; 95% confidence interval [CI] = 0.75, 0.99). This effect was driven by outcomes among younger adolescent women (HR = 0.80; 95% CI = 0.65, 0.96). There was also a trend toward significance for women of Mexican heritage (HR = 0.74; 95% CI = 0.49, 1.07), although this effect might be attributed to individual agency performance.Conclusions. Home visitation using the Nurse–Family Partnership model had measurable effects on birth spacing in Latina women.
Impact of Arizona’s SB 1070 Immigration Law on Utilization of Health Care and Public Assistance Among Mexican-Origin Adolescent Mothers and Their Mother Figures
Authors: Toomey Russell B. , Umaña-Taylor Adriana J. , Williams David R. , Harvey-Mendoza Elizabeth , Jahromi Laudan B. , Updegraff Kimberly A. 
Published: December 2013

Objectives. We examined the impact of Arizona’s “Supporting Our Law Enforcement and Safe Neighborhoods Act” (SB 1070, enacted July 29, 2010) on the utilization of preventive health care and public assistance among Mexican-origin families.Methods. Data came from 142 adolescent mothers and 137 mother figures who participated in a quasi-experimental, ongoing longitudinal study of the health and development of Mexican-origin adolescent mothers and their infants (4 waves; March 2007–December 2011). We used general estimating equations to determine whether utilization of preventive health care and public assistance differed before versus after SB 1070’s enactment.Results. Adolescents reported declines in use of public assistance and were less likely to take their baby to the doctor; compared with older adolescents, younger adolescents were less likely to use preventive health care after SB 1070. Mother figures were less likely to use public assistance after SB 1070 if they were born in the United States and if their post–SB 1070 interview was closer to the law’s enactment.Conclusions. Findings suggest that immigration policies such as SB 1070 may contribute to decreases in use of preventive health care and public assistance among high-risk populations.
The Effects of Breastfeeding Exclusivity on Early Childhood Outcomes
Authors: Jenkins Jade Marcus , Foster E. Michael 
Published: December 2013

Objectives. We examined the relationship between breastfeeding exclusivity and duration and children’s health and cognitive outcomes at ages 2 and 4 years.Methods. We used the Early Childhood Longitudinal Study—Birth Cohort, a nationally representative sample of 10 700 children born in the United States in 2001. Parent interviews and child assessments were conducted in measurement waves at 9 months, 2 years, 4 years, and in kindergarten, with the focus on ages 2 and 4 years. We employed propensity scores as a means of adjusting for confounding involving observed characteristics.Results. Outcome analyses using propensity scores showed some small effects of breastfeeding on key outcomes at age 4 years but not at age 2 years. Effects appeared to be concentrated in reading and cognitive outcomes. Overall, we found no consistent evidence for dosage effects of breastfeeding exclusivity. Our sensitivity analyses revealed that a small amount of unobserved confounding could be responsible for the resulting benefits.Conclusions. Our study revealed little or no effect of breastfeeding exclusivity and duration on key child outcomes.
Memory consolidation — Mechanisms and opportunities for enhancement
Authors: Shaikh Netasha , Coulthard Elizabeth 
Published: December 2013

Abstract
Memory consolidation is the process by which relevant information is selected and transferred from a short-term, fragile state, into a stable, longer term domain from which it can be recalled. Effective memory underpins our ability to carry out everyday activities. When memory consolidation fails, such as in Alzheimer’s disease, the consequences can be devastating. Understanding the neurobiology of memory will help develop treatments for patients with memory loss. Here we describe the myriad processes involved in memory consolidation, including cholinergic and dopaminergic neurotransmission predominantly in hippocampal networks. We discuss established therapies as well as potential novel strategies for boosting cognition. Future approaches to enhancement of memory consolidation include not only pharmacological and neurosurgical treatments, but also lifestyle interventions — for example, modifications to sleep, exercise and diet.
La gauche républicaine et la conquête de l'Algérie, de la prise d'Alger à la reddition d'Abd el-Kader (1830-1847)
Authors: Darriulat Philippe 
Published: December 2013

La période de la première colonisation de l'Algérie, celle qui s'ouvre avec la prise d'Alger le 5 juillet 1830 et se clôt avec la reddition d'Abd el-Kader le 23 décembre 1847, se confond presque parfaitement avec le règne de Louis Philippe. C'est aussi le moment où apparaît pour la première fois en France un Parti républicain distinct des autres partis. Les archives de presse (la Tribune, la Réforme, le Journal du Peuple, l'Intelligence, le Populaire) nous permettent d'étudier l'attitude de ces militants, et notamment des plus radicaux d'entre eux, vis-à-vis de la question coloniale.
Très homogènes à ce sujet, les républicains manifestent tous, dès cette époque, un profond sentiment nationaliste qui les pousse non seulement à prôner une colonisation totale de l'Algérie, mais aussi son intégration à la France. Ils y voient en effet à la fois un moyen de « civiliser » des peuples jugés « barbares » et aussi d'assurer la domination française — la nation des « Lumières » — sur le monde et notamment par rapport à son principal concurrent : l'Angleterre, le pays capitaliste par excellence. Rêvant d'une organisation démocratique de la société coloniale dont pourraient « progressivement » bénéficier les « peuples autochtones », c'est au nom des valeurs de Révolution française que l'extrême gauche se fait alors l'avocat d'une Algérie française, conquise par tous les moyens, y compris la force. N'hésitant pas à accuser les libéraux au pouvoir (le « parti de l'étranger») de ne pas s'engager avec suffisamment de volonté dans cette aventure, ces militants en font une question de principe qu'ils lient étroitement à leur conception de la Nation.
La pénurie de main d'œuvre indigène dans les plantations européennes de l'Ouest-Cameroun
Authors: Tanga-Onana Joseph 
Published: December 2013

To exploit the resources of the soil and undersoil, placed under French mandate, colonists in general and Europeans farmers of West-Cameroon and Mungo in particular used « indigenous » man power. But as from 1935, the latter faced great difficulties in recruiting a cheap and adequate number of this man power.
The author of this article lists the causes as ivell as analyses solutions suggested by colonists and the French colonial Administration to solve this delicate and complex problem of « indigenous » man power shortage in the great plantations of West Cameroon and Mungo (1935-1938).