Influence of metal gate and capping film stress on TANOS cell performance

In this work it is shown that film stress in the gate stack of TANOS NAND memories plays an important role for cell device performance and reliability. Tensile stress induced by a TiN metal gate deteriorates TANOS cell retention compared to TaN gate material. However, the erase saturation level as well as cell endurance is improved by the use of a TiN gate. This trade-off between retention and erase saturation for TANOS cells is elaborated in detail.     

Application of the hybrid Hopkins–Abbe method in full-chip OPC

The hybrid Hopkins–Abbe method is presented and shown to resolve the problem of the traditional Hopkins theory, namely the requirement for constant mask diffraction efficiencies. Simulation of electromagnetic scattering from the mask that takes into account the oblique angles of incidence from the illumination is performed by application of the domain decomposition method that is extended for offaxis illumination. Examples of 45 nm and 32 nm lines and spaces through pitch and through focus are presented to demonstrate the validity and accuracy of the hybrid Hopkins–Abbe method. The results obtained are in excellent agreement with a rigorous and independent (third party) simulator.     

Force control for hydraulic load simulator using self-tuning grey predictor – fuzzy PID

Hydraulic systems play an important role in modern industry for the reason that hydraulic actuator systems have many advantages over other technologies with electric motors, as they possess high durability and the ability to produce large forces at high speeds. Therefore, the hydraulic actuator has a wide range of application fields such as hydraulic punching, riveting, pressing machines, and molding technology, where controlled forces or pressures with high accuracy and fast response are the most significant demands. Consequently, many hybrid actuator models have been developed for studying how to control forces or pressures with best results.This paper presents a kind of hydraulic load simulator for conducting performance and stability testing related to the force control problem of hydraulic hybrid systems. In the dynamic loading process, perturbation decreases control performance such as stability, frequency response, and loading sensitivity decreasing or bad. In order to improve the control quality of the loading system while eliminating or reducing the disturbance, a grey prediction model combined with a fuzzy PID controller is suggested. Furthermore, fuzzy controllers and a tuning algorithm are used to change the grey step size in order to improve the control quality. The grey prediction compensator can improve the system settle time and overshoot problems. Simulations and experiments on the hydraulic load simulator are carried out to evaluate the effectiveness of the proposed control method when applied to hydraulic systems with various external disturbances encountered in real working conditions.     

Nth order current mode universal filter using MOCCCIIs

This article presents a new current mode single-input-multiple-output nth order universal filter. The proposed circuit employs (n + 1) number multiple output second generation current conveyors and n number grounded capacitors only. Presented circuits can realize current mode low pass, high pass, band pass, notch and all pass responses simultaneously at different high output impedance terminals. The current mode filter circuit provides low input impedance by selecting the proper value of bias current and also has high output impedance, which is suitable for cascading. The circuit offers some important features such as resistor less realization, no passive component matching constraints, low sensitivity, electronic tunability and active-C realization. The functionality of the proposed filter circuit is tested with the PSPICE simulation, which is found to agree well with the proposed theory.     

Solid-state intermetallic compound layer growth between copper and 95.5Sn-3.9Ag-0.6Cu solder

Long-term, solid-state intermetallic compound (IMC) layer growth was examined in 95.5Sn-3.9Ag-0.6Cu (wt.%)/copper (Cu) couples. Aging temperatures and times ranged from 70°C to 205°C and from 1 day to 400 days, respectively. The IMC layer thicknesses and compositions were compared to those investigated in 96.5Sn-3.5Ag/Cu, 95.5Sn-0.5Ag-4.0Cu/Cu, and 100Sn/Cu couples. The nominal Cu₃Sn and Cu₆Sn₅ stoichiometries were observed. The Cu₃Sn layer accounted for 0.4–0.6 of the total IMC layer thickness. The 95.5Sn-3.9Ag-0.6Cu/Cu couples exhibited porosity development at the Cu₃Sn/Cu interface and in the Cu₃Sn layer as well as localized “plumes” of accelerated Cu₃Sn growth into the Cu substrate when aged at 205°C and t>150 days. An excess of 3–5at.%Cu in the near-interface solder field likely contributed to IMC layer growth. The growth kinetics of the IMC layer in 95.5Sn-3.9Ag-0.6Cu/Cu couples were described by the equation x=x_o+Atⁿexp [−ΔH/RT]. The time exponents, n, were 0.56±0.06, 0.54±0.07, and 0.58±0.07 for the Cu₃Sn layer, the Cu₆Sn₅, and the total layer, respectively, indicating a diffusion-based mechanism. The apparent-activation energies (ΔH) were Cu₃Sn layer: 50±6 kJ/mol; Cu₆Sn₅ layer: 44±4 kJ/mol; and total layer: 50±4 kJ/mol, which suggested a fast-diffusion path along grain boundaries. The kinetics of Cu₃Sn growth were sensitive to the Pb-free solder composition while those of Cu₆Sn₅ layer growth were not so.     

Interdigitated back‐contact heterojunction solar cell concept for liquid phase crystallized thin‐film silicon on glass

We present an interdigitated back‐contact silicon heterojunction system designed for liquid‐phase crystallized thin‐film (~10 µm) silicon on glass. The preparation of the interdigitated emitter (a‐Si:H(p)) and absorber (a‐Si:H(n)) contact layers relies on the etch selectivity of doped amorphous silicon layers in alkaline solutions. The etch rates of a‐Si:H(n) and a‐Si:H(p) in 0.6% NaOH were determined and interdigitated back‐contact silicon heterojunction solar cells with two different metallizations, namely Al and ITO/Ag electrodes, were evaluated regarding electrical and optical properties. An additional random pyramid texture on the back side provides short‐circuit current density (j_SC) of up to 30.3 mA/cm² using the ITO/Ag metallization. The maximum efficiency of 10.5% is mainly limited by a low of fill factor of 57%. However, the high j_SC, as well as V_OC values of 633 mV and pseudo‐fill factors of 77%, underline the high potential of this approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Time-hopping and frequency-hopping multiple-access packetcommunications

Time-hopping and frequency-hopping multiple-access (TH/FHMA) packet communication systems are proposed and investigated. In TH/FHMA communication systems, a message packet is encoded into several subpackets via a Reed-Solomon error correcting code. The subpackets are transmitted over the channel using time-hopping and frequency-hopping patterns. It is assumed that the channel is noiseless and the side information is perfect so that all subpacket collisions can be correctly detected. Slot-synchronous and totally asynchronous TH/FHMA systems are analyzed in detail, and they are shown to have excellent throughputs at small packet erasure rates. Various time-hopping techniques which significantly reduce the multiple-access interference are developed     

A Methodology for Architecture Exploration of Heterogeneous Signal Processing Systems

We present a methodology for the exploration of signal processing architectures at the system level. The methodology, named SPADE, provides a means to quickly build models of architectures at an abstract level, to easily map applications, modeled as Kahn Process Networks, onto these architecture models, and to analyze the performance of the resulting system by simulation. The methodology distinguishes between applications and architectures, and uses a trace-driven simulation technique for co-simulation of application models and architecture models. As a consequence, architecture models need not be functionally complete to be used for performance analysis while data dependent behavior is still handled correctly. We have used the methodology for the exploration of architectures and mappings of an MPEG-2 video decoder application.     

Co-RAM: combinational logic synthesis applied to softwarepartitions for mapping to a novel memory device

We introduce the application of current techniques for hardware synthesis of combinational logic blocks to large-scale software partitions for eventual implementation of these partitions in a novel memory device called "Co-RAM." The novelty of our approach is based upon the observation that a wide variety of largescale software functionality can be considered "stateless" by conventional hardware synthesis tools and so may be realized as combinational logic. By limiting the functions placed in memory to combinational functions, we eliminate conventional synchronization overhead associated with coprocessors. A significant aspect of Co-RAM is that it is a system design concept that inherently merges hardware and software design styles at the system level, impacting programming styles, system build approaches, and the programmer's view of the underlying machine. A direct consequence of viewing the functionality as combinational is that the system state is not partitioned with the tasks. By Considering Co-RAM functionality to be stateless with respect to system state, Co-RAM functionality is inlined around the advancement of effectively unpartitioned system state. The rules for procedural combinational logic synthesis are shown to apply to a wide variety of software partitions. Results of our investigation project speedups of 8× to 1000× for a range of algorithms of varying problem size and for projected devices ranging from conventional field programmable gate arrays (FPGAs) to highly specific combinational logic devices     

Locating the eye in human face images using fractal dimensions

Facial feature extraction is an important step in many applications such as human face recognition, video conferencing, surveillance systems, human computer interfacing etc. The eye is the most important facial feature. A reliable and fast method for locating the eye pairs in an image is vital to many practical applications. A new method for locating eye pairs based on valley field detection and measurement of fractal dimensions is proposed. Possible eye candidates in an image with a complex background are identified by valley field detection. The eye candidates are then grouped to form eye pairs if their local properties for eyes are satisfied. Two eyes are matched if they have similar roughness and orientation as represented by fractal dimensions. A modified approach to estimating fractal dimensions that is less sensitive to lighting conditions and provides information about the orientation of an image under consideration is proposed. Possible eye pairs are further verified by comparing the fractal dimensions of the eye-pair window and the corresponding face region with the respective means of the fractal dimensions of the eye-pair windows and the face regions. The means of the fractal dimensions are obtained based on a number of facial images in a database. Experiments have shown that this approach is fast and reliable