Fully 3D self-consistent quantum transport simulation of Double-gate and Tri-gate 10 nm FinFETs

We utilize a fully self-consistent 3D quantum mechanical simulator based on the Contact Block Reduction (CBR) method to investigate the effects of fin height and unintentional dopant on the device characteristics of a 10-nm FinFET device. The per-fin height off-current is found to be relatively insensitive to fin height while the corresponding per fin height on-current may significantly depend on fin height due to the stronger confinement with decreasing fin height. Also gate leakage is found to show similar behavior as device on-current with decreasing fin height. Tri-gate (TG) FinFET is found to show better performance compared to Double-gate (DG) FinFET, with the exception of gate leakage current. Simulation results show that an unintentional dopant within the channel can significantly alter device characteristics depending on its position and applied biases. In addition, the effects of unintentional dopant are found to be stronger at high drain bias than at low drain bias.     

Can silicon FinFETs satisfy ITRS projections for high performance 10 nm devices?

We utilize a fully self-consistent quantum mechanical simulator based on CBR method to optimize 10 nm FinFET devices to meet ITRS projections for High Performance (HP) logic technology devices. Fin width, gate oxide thickness, and doping profiles are chosen to reflect realistic values. We find that the device on-current approaching the value projected by ITRS for HP devices can be obtained using unstrained conventional (Si) channel. Our simulation results also show that quantum nature of transport in ultra small devices significantly enhances the intrinsic switching speed of the device. In addition, small signal analysis has been performed. Sensitivity of device performance to the process variation at room temperature has also been investigated.     

Full band Monte Carlo simulation of dislocation effects on 250 nm AlGaN-GaN HEMT

In this work, we present a full band Monte Carlo simulation of the effects of dislocation scattering on the performance of a 0.25 μm AlGaN/GaN HEMT (high electron mobility transistor). We performed a full characterization of the device and validated the simulation results with experimental data (Lee et al. in IEEE Electron. Dev. Lett. 24:613–615, [2003]). Here we show a study of the DC device performance as a function of the density of thread dislocations.     

Calculation of Fin width for bulk inversion in Si FinFET by applying supersymmetry

The transition from surface inversion to bulk inversion in a Si FinFET is investigated in this paper using supersymmetric quantum mechanics. A double quantum well potential, which is the supersymmetric partner of a harmonic oscillator potential, was chosen. The fraction of charge residing inside the bulk was calculated as a function of fin width and electron density. For any electron density, more charge resides in the bulk as the fin width decreases. On the other hand, for a fixed fin width, charges move to the surface as the electron density increases. It was found that in Si FinFET for the electron density of 3×10¹² cm⁻² bulk inversion occurs when the fin width is about 8 nm.     

Ultrahigh on/off-current ratio γ-graphyne-1 nanotube-based sub-10-nm TFET modeling and simulation

Journal of Computational Electronics - The use of γ-graphyne-1 nanotubes (GyNTs) in tunneling field effect transistors (TFETs) suppresses ambipolarity and enhances the subthreshold...     

Effects of high voltage discharge on the human bodies of workers

In this paper,as it is reported,through mechanism analysis,calculation,testing,measuring in the site and the observation ofbiologic effect on workers as well as the peripheral blood test in vitro,there are low energy X-ray and so forth produced due to high volt-age discharge which are harmful physical and chemical factors.Theexistence of these harmful factors affect workers' health to a certaindegree.The observed biologic indexes are those of peripheral bloodcell effect,lymphocyte,micronuclear,chromosomal aberration,sisterchromatid exchange,blood serum immune globulin,electroen-cephalogram and brain blood current gram. The vitro peripheralblood test indexes are including those of chromosmal aberration,sister chromatid exchange and blood serum immune globulin.Theresults obtained from the said observation and testing express thatthe above mentioned indexes have obvious significance after thecomparison of those between test group and control group treated bystatistics (i.e.P<0.05).Further,the test results also point out that theenvironment of high voltage discharge will creat injury to the workers,therefore a detail research should be taken.     

The Study of the Effects of Reading Factors on Incidental Vocabulary Acquisition

To figure out the most robust factors influencing incidental vocabulary acquisition （IVA） performance, in this paper three reader variables are identified based on literature review, i.e., reading proficiency, sight vocabulary and content schema; and an investigation is conducted to search for their different impacts. After the analysis of the collected data by SPSS 10.0, the results suggested that individual difference in IVA is largely caused by the difference in reading ability and previous vocabulary knowledge. Therefore, to foster learners＇ IVA ability, EFL teachers need to help students develop independent reading strategies for IVA, provide material suitable to students＇ level and enrich their background knowledge.     

Effects of electrified railways on quality of electric energy supply in urban power systems

IntroductionBeing of great value to railway transport and hence to nationaleconomy,electrification of railways has been carried out very rapidlyin China in the past 30 years.By the end of 1990,some 6941 km ofelectrified railways have been opened to traffic and about 16,000 kmor one fourth of the total railway length are expected to be electrified,accounting for 45% of the total railway freight volume.At present,Shaanxi Province ranks first with respect to total     

Effects of CeO2 Coating on Oxidation Behavior of TP304H Steel in High-Temperature Water Vapor

Oxidation behaviors of TP304H steel with electrophoresis deposited CeO2 coating in water vapor were studied at 610℃ -770℃ for 65 h. The results showed that CeO2 coating reduced effectively the oxidation rate of TP304H. Analysis with SEM and EDS showed the structure of oxide scale turned from multi-layer to mono-layer and oxide scale with high Cr content formed on the surface of CeO2 coating while inner oxidation disappeared. Based on test results and CeO2 characters that Ce ion can vary between Ce^4 and Ce^3 under oxygen-rich and oxygen-poor environment, it is concluded that CeO2 coating acts as a barrier to prevent oxygen inner diffusion and the partial oxygen pressure of CeO2 coating-substrate interface is limited. Cr first diffuses outward across CeO2 coating and forms oxide scale on the surface, which delays formation of Fe oxide.     

The effect of dielectric mismatch on excitons and trions in cylindrical semiconductor nanowires

We investigated the energy levels of excitons (X) and trions (X ^±) in free-standing nanowires with strong lateral carrier confinement. Within the adiabatic approximation the two (resp. three) particle problem reduces to an effective one (resp. two) dimensional Schrödinger equation for the relative motion which is solved numerically. Dielectric mismatch effects are taken into account that result in a distorted Coulomb interaction between the charged particles. We obtain the X and X ^± binding energies as function of the dielectric mismatch ratio. To obtain these energies, we constructed tractable analytical expressions for the effective potential in the wire which significantly reduces the amount of computational time.     

Analysis and design of rectangular microstrip antenna on two-layer substrate materials at terahertz frequency

In this paper, an effective permittivity of the two-layer dielectric substrate material has been analyzed to enhance the electrical performance of the rectangular microstrip patch antenna at terahertz frequency. The frequency dependent effective dielectric permittivity of the substrate materials has been evaluated and result has been compared with finite integral technique based CST Microwave Studio a commercially available simulator. The input impedance characteristic with electrical performance of the rectangular microstrip patch antenna on two-layer substrate materials has also been analyzed at 600 GHz. Manipulation in the input impedance characteristic of the antenna has led to a slow wave structure. This slow wave structure has been examined at 542 GHz, and improvement in the performance has been observed without increasing the overall dimension of the proposed antenna.     

The role of the source and drain contacts on self-heating effect in nanowire transistors

We find that self-heating effects are not pronounced in silicon nanowire transistors with channel length 10 nm even in the presence of the wrap-around oxide. We observe a maximum current degradation of 6% for V _G =V _D =1.0 V in a structure in which the metal gates are far away from the channel. The overall small current degradation is attributed to the significant velocity overshoot effect in these structures. The lattice temperature profile shows moderate temperature rise and velocity of the carriers is slightly deteriorated due to self-heating effects when compared to isothermal simulations.     

Effects of post-treatments on the electrochemical properties of solid-state reacted Li4Ti5O12—high energy milling and annealing

This study is designed and performed to verify whether nano-sized Li₄Ti₅O₁₂ particles can be acquired by simple high energy milling from the economic solid-state reacted coarse powder for high power lithium ion battery applications. For this, Li₄Ti₅O₁₂ is synthesized by heat treatment at 800 and 850°C for 3?h using Li₂CO₃ and TiO₂, followed by high energy milling. Even though a comparable particle size to that of expensive wet chemical methods, or even a smaller particle size of 25?nm, can be acquired by 5?h of milling, the electrochemical properties of the particles are found to be deteriorated due to the decrease in Li₄Ti₅O₁₂ crystallinity associated with the milling. On the other hand, a subsequent annealing at 750°C for the milled powder is shown to recover both the capacity and rate capability of the anode electrode owing to the increased crystallinity, indicating the importance of particle crystallinity besides a fine particle size for the enhanced electrochemical properties for high power applications.     

Effects of doping Y2O3 on the microstructure and electrical properties of ZnO-Bi2O3−based varistor ceramics

ZnO-based varistor ceramics doped with different amount of Y₂O₃ have been made by two-step solid-state reaction route including the pre-calcination and subsequent sintering procedures, using nanosized ZnO powder and corresponding additives as the raw material. The phase composition, microstructure and electrical properties were studied by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM) and direct current electrical measurement. It was found that the electrical properties of the varistor ceramics sintered at 950 °C from the powder pre-calcined at 800 °C were enhanced by doped appropriate amount of Y₂O_3. Particularly, ZnO varistors doped with 1.2 mol% Y₂O₃ possessed the best comprehensive electrical properties with the breakdown field of 2113 V/mm, the nonlinear coefficient of 184.6 and the leakage current of 0.4 μA. Y₂O₃ phase, Y-rich phase and the other secondary phase particles were confirmed to distribute along the grain boundaries of predominant ZnO grains from XRD and SEM analyses. The results illustrated that doping Y₂O₃ should be a promising route to obtain varistor ceramics with excellent electrical properties.

     

Effects of ZnO–xV2O5 substitution on the microstructure and microwave dielectric properties of ZnNb2O6 ceramics

The ZnO–xV₂O₅ substituted ZnNb₂O₆ ceramics with chemical formula Zn(Nb_0.9V _x )₂O_5.5+5x (0?<?x?≤?0.10) were prepared by solid-state reaction route. The densities, microstructures and microwave dielectric properties were investigated according to the different substitution amount of V₂O₅ and sintering temperature. A small amount of substitution of ZnO–xV₂O₅ was effective to lower sintering temperature of ZnNb₂O₆ ceramics from 1,150 °C to 900 °C. The V₂O₅ substitution led to growth of rod-like grains with the help of liquid phase formed from ZnO and V₂O₅. The dielectric properties depended largely on the amount of V₂O₅ substitution and sintering temperature. The dense ceramics with x?=?0.05 were obtained at 950 °C, which had excellent dielectric properties: ?_r?=?24, Q?×?f?=?72,800 GHz and τ_f?=??63.5 ppm/°C. The interface analysis for cofired multilayer composites composed of the present LTCC and metal Ag demonstrated good co-firing chemical compatibility at co-sintering temperature.     

Design of random doping fluctuation resistant structures of semiconductor devices

An automated technique is presented for the computation of the doping profiles that minimize the intrinsic fluctuations of various parameters induced by random doping fluctuations in semiconductor devices. The technique is based on the computation of the doping sensitivity functions of the parameters under consideration and the constrained minimization of the standard deviation of fluctuations by using the Lagrange multipliers technique. The technique is then applied to the minimization of the random doping induced fluctuations of the threshold voltage in 40-nm channel length MOSFET device.     

An advanced description of oxide traps in MOS transistors and its relation to DFT

Recently, an advanced model for defects in the insulating regions of semiconductor devices has been suggested, which can explain the removable component of the negative bias temperature instability (NBTI) and recoverable random telegraph/flicker noise. We give a brief introduction to the atomic scale physics behind the model and show how model parameters can be extracted from density functional theory (DFT) calculations. The central link between DFT calculations and device simulation is the carrier energy dependent part of the capture cross section, the line shape function. Calculations of the line shape functions of model defect structures using a simple harmonic approximation are presented. The calculations show a considerable shift in the oscillator frequency upon charge state transitions for the defects investigated.