Impact of Mole Fractions due to Work Function Variability (WFV) of Metal Gate on Electrical Parameters in Strained SOI-FinFET

In the recent sub-20 nm technology node, the process variability issues have become a major problem for scaling of MOS devices. We present a design for a strained Si/SiGe FinFET on an insulator using a 3D TCAD simulator. The impact of metal gate work function variability (WFV) on electrical parameters is studied. Such impact of WFV for different mole fractions (x) of the SiGe layer in a strained SOI-FinFET with varying grain size is presented. The results show that as the mole fraction is increased, the variability in threshold voltage (σVT) and off current (σIoff) is decreased; while, the variability of on-current (σIon) is increased. A notable observation is the distribution of electrical parameters approaches a normal distribution for smaller grain sizes.     

Understanding silica-supported metal catalysts: Pd/silica as a case study

Supported metal catalysts, particularly noble metals supported on SiO₂, have attracted considerable attention due to the importance of the silica–metal interface in heterogeneous catalysis and in electronic device fabrication. Several important issues, e.g., the stability of the metal–oxide interface at working temperatures and pressures, are not well-understood. In this review, the present status of our understanding of the metal–silica interface is reviewed. Recent results of model studies in our laboratories on Pd/SiO₂/Mo(1 1 2) using LEED, AES and STM are reported. In this work, epitaxial, ultrathin, well-ordered SiO₂ films were grown on a Mo(1 1 2) substrate to circumvent complications that frequently arise from the silica–silicon interface present in silica thin films grown on silicon.     

Ammonia Decomposition on Ir(100): From Ultrahigh Vacuum to Elevated Pressures

Ammonia decomposition on Ir(100) has been studied over the pressure range from ultrahigh vacuum to 1.5 Torr and at temperatures ranging from 200 to 800 K. The kinetics of the ammonia decomposition reaction was monitored by total pressure change. The apparent activation energy obtained in this study (84 kJ/mol) is in excellent agreement with our previous studies using supported Ir catalysts (Ir/Al₂O₃ 82 kJ/mol). Partial pressure dependence studies of the reaction rate yielded a positive order (0.9±0.1) with respect to ammonia and negative order (–0.7 ±0.1) with respect to hydrogen. Temperature-programmed desorption data from clean and hydrogen co-adsorbed Ir(100) surfaces indicate that ammonia undergoes facile decomposition on both these surfaces. Recombinative desorption of N₂ is the rate-determining step with a desorption activation energy of 63 kJ/mol. Co-adsorption data also indicate that the observed negative order with respect to hydrogen pressure is due to enhancement of the reverse reaction (NH _x + H NH _x+1, x=0–2) in the presence of excess H atoms on the surface.     

Propagation of correlations in local random quantum circuits

We derive a dynamical bound on the propagation of correlations in local random quantum circuits—lattice spin systems where piecewise quantum operations—in space and time—occur with classical probabilities. Correlations are quantified by the Frobenius norm of the commutator of two positive operators acting on disjoint regions of a one-dimensional circular chain of length L. For a time \(t=O(L)\), correlations spread ballistically to spatial distances \(\mathcal {D}=t\), growing at best, diffusively with time for any distance within that radius with extensively suppressed distance- dependent corrections. For \(t=\varOmega (L^2)\), all parts of the system get almost equally correlated with exponentially suppressed distance- dependent corrections and approach the maximum amount of correlations that may be established asymptotically.     

Human SMILE-Derived Stromal Lenticule Scaffold for Regenerative Therapy: Review and Perspectives

A transparent cornea is paramount for vision. Corneal opacity is one of the leading causes of blindness. Although conventional corneal transplantation has been successful in recovering patients’ vision, the outcomes are challenged by a global lack of donor tissue availability. Bioengineered corneal tissues are gaining momentum as a new source for corneal wound healing and scar management. Extracellular matrix (ECM)-scaffold-based engineering offers a new perspective on corneal regenerative medicine. Ultrathin stromal laminar tissues obtained from lenticule-based refractive correction procedures, such as SMall Incision Lenticule Extraction (SMILE), are an accessible and novel source of collagen-rich ECM scaffolds with high mechanical strength, biocompatibility, and transparency. After customization (including decellularization), these lenticules can serve as an acellular scaffold niche to repopulate cells, including stromal keratocytes and stem cells, with functional phenotypes. The intrastromal transplantation of these cell/tissue composites can regenerate native-like corneal stromal tissue and restore corneal transparency. This review highlights the current status of ECM-scaffold-based engineering with cells, along with the development of drug and growth factor delivery systems, and elucidates the potential uses of stromal lenticule scaffolds in regenerative therapeutics.     

<Emphasis Type="Bold">Analysis of Spatio-temporal Characteristics and Regional Frequency of Droughts in the Southern Peninsula of India</Emphasis>

A detailed regional drought study is carried out in the southern peninsula of India to characterize the spatio-temporal nature of droughts and to predict the drought magnitudes for various probabilities in the homogeneous drought regions. The method of several random initializations of the cluster centres of the K-means algorithm is suggested for the identification of the initial regions in the context of drought regionalization, which is shown to perform better than the initialization from the Ward’s algorithm and the Ward’s algorithm itself. The peninsula is classified into seven spatially well-separated homogeneous drought regions. The robust L-moment framework is used for the regional frequency analysis of drought magnitudes computed using the standardized precipitation index. The Pearson type III is found to be appropriate for regional drought frequency analysis in six of the regions, while the robust Wakeby distribution is suggested for one region. Low magnitude droughts are frequent and dominant in the northern part of west coast, the north-eastern coast and its adjoining inland region, while high magnitude droughts are less in number and are experienced in semi-arid central part, southern part of western coast, south-eastern part and north-western inland region. The spatial maps of drought magnitudes indicate that at higher return periods (100 and 200 years) the south-eastern part of the peninsula is likely to encounter high magnitude droughts, while the central region is likely to experience the same at lower return periods (10 and 50 years). Hence these regions need to be given special importance in the drought mitigation planning activities.     

A Comprehensive Survey of Emergency Communication Network and Management

Wireless Personal Communications - The performance of wireless communication network is important in emergency rescue operations while ensuring optimum usage of limited wireless resources. Due to...     

Interdiffusion in the Fe-Pt System

Diffusion-couple experiments are conducted in the Fe-Pt system. The phase boundary compositions of the phases measured in this study are found to be different than the compositions published previously. In the γ-FePt solid solution, the interdiffusion coefficient increases with the Pt content up to 25 at. pct Pt. Fe is the faster diffusing species in this phase. The trend in the interdiffusion coefficient is explained with the help of calculated driving force for diffusion. To reduce errors, the average interdiffusion coefficients are calculated in the FePt and FePt₃ compounds.     

Ultra-high temperature (>300 °C) suspended thermodiode in SOI CMOS technology

This paper reports for the first time on the performance and long-term stability of a silicon on insulator (SOI) thermodiode with tungsten metallization, suspended on a dielectric membrane, at temperatures beyond 300 °C. The thermodiode has been designed and fabricated with minute saturation currents (due to both small size and the use of SOI technology) to allow an ultra-high temperature range and minimal non-linearity. It was found that the thermodiode forward voltage drop versus temperature plot remains linear up to 500 °C, with a non-linearity error of less than 7%. Extensive experimental results on performance of the thermodiode that was fabricated using a Complementary Metal Oxide Semiconductor (CMOS) SOI process are presented. These results are backed up by infrared measurements and a range of 2-D (dimension) and 3-D simulations using ISE and ANSYS software. The on-chip drive electronics for the thermodiode and the micro-heater, as well as the sensor transducing circuit were placed adjacent to the membrane. We demonstrate that the thermodiode is considerably more reliable in long-term direct current operation at high temperatures when compared to the more classical resistive temperature detectors (RTDs) using CMOS metallization layers (tungsten or aluminum). We also compare a membrane thermodiode with a reference thermodiode placed on the silicon substrate and assess their relative performance at elevated temperatures. The experimental results from this comparison confirm that the thermodiode suffers minimal piezo-junction/piezo-resistive effects.     

Fault estimation and tolerant control for discrete‐time switched systems with sojourn probabilities

This paper addresses the issue of fault estimation and accommodation for a discrete‐time switched system with actuator faults. Here, we assume that the sojourn probabilities are known a priori. By using the reduced‐order observer method, the sojourn probability approach, and the Lyapunov technique, a fault estimation algorithm is obtained for the considered system. The main objective of this work is to design a dynamic output feedback fault‐tolerant controller based on the obtained fault estimation information such that the closed‐loop discrete‐time switched system with available sojourn probabilities is robustly mean‐square stable and satisfies a prescribed mixed and passivity disturbance attenuation level in the presence of actuator faults. More precisely, a dynamic output feedback fault‐tolerant controller is established in terms of linear matrix inequalities. Finally, numerical examples are provided to illustrate the usefulness and effectiveness of the proposed design technique.