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Low density parity check codes is decoded by bit flipping algorithm and sum product algorithm. Bit flipping algorithm has low complexity and poor performance. To achieve trade-off between performance and complexity weights of the inversion function modified by using variance of the received values. These modifications improve performance with mild increase in the computations. It decreases in average number of iterations for maintaining high reliability and higher speed decoding.

In this paper, we discuss a technique for selective GeO x -scavenging which creates a GeO x -free interfacial layer (IL) on Si 1−x Ge x substrates. This process reduces interface trap density (N it ) and increases high-field hole mobility in Si 1−x Ge x pFETs. In addition, we identify the existence of electronic defect levels close to the Si 1−x Ge x band edges associated with the Ge surface concentration at the Si 1−x Ge x /IL interface. These electronic defects act as carrier scattering centers severely degrading the channel mobility and modulate the device threshold voltage. By successfully eliminating the GeO x component in the IL and electronic defects states at the Si 1−x Ge x /IL interface, high channel carrier mobility over a wide range of inversion carrier density in compressively-strained Si 1−x Ge x channel pFETs is demonstrated.

This paper presents a system of grid connected photovoltaic (PV) to the monitoring point of maximum power (MPPT). The voltage source inverter (VSI) is connected between the dc output of photovoltaic system and ac grid. The control strategy applied is based on theory of instantaneous reactive power (p-q theory). According to this proposed PV system send active power to the grid at the same time the reactive power of load and harmonics will eliminate at change in both irradiation and load condition. During no sunlight system is available only reactive power and harmonic compensation. The applicability of our system tested in simulation in Matlab / Simulink.

We demonstrate a technique for selective GeO x -scavenging which creates a GeO x -free IL on Si 1−x Ge x substrates. This process reduces N it by >60% to 2e11 and increases high-field mobility at N inv =1e13 cm−2 by ∼1.3× in Si 0.6 Ge 0.4 pFETs with sub-nm EOT.

Bias Temperature Instability (BTI) is a tremendous reliability concern for deeply scaled CMOS technologies, and is the limiting mechanism for further inversion layer thickness (Tinv) scaling for future nodes [1]. Replacement Metal Gate technologies are of particular concern, since the gate stack is not exposed to the high temperature source/drain anneals. We have identified four strategies for reducing BTI in Replacement metal gate technologies: Rapid Thermal Anneal (RTA) optimization, optimization of the HfO2 layer thickness, introducing a gate dielectric dopant for NBTI reduction, and effective Work Function tuning. Judiciously combining these four techniques enable further Tinv scaling for 10 nm and below.

We identified unique device width and length dependencies of Vt for FinFET Replacement Metal Gate (RMG). Choice of fill metal is important to obtain a flat Vt-Wdes trend. We proposed a new model for Vt-Lg roll-up for High-k last RMG and demonstrated a flat Vt-Lg trend via optimization of High-k and MOL films based on the understanding.

DC and AC NBTI in deep EOT scaled HKMG p-MOSFETs with different IL (scaled to sub 2A) are measured by UF-MSM method with 10μs delay. A model with interface trap generation (ΔV IT-IL ) at Si/IL interface, hole trapping (ΔV HT ) in IL bulk and trap generation (ΔV IT-HK ) linked to H passivated Oxygen vacancy (Ov-H) defects in IL/HK interfacial transition layer has been proposed. The existence of Ov defects and their energy levels are verified using DFT simulation. The model can successfully predict V T shift (ΔV T ) during and after DC stress, dependence on pulse duty cycle (PDC) and frequency (f) for AC stress, and gate insulator process dependence with consistent set of parameters. Impact of EOT scaling on DC and AC NBTI is studied, and end-of-life degradation has been estimated.

Independent Trap Generation (TG) monitors such as DCIV and SILC have been used during NBTI, PBTI (and TDDB) stress in differently processed HKMG devices. TG from DCIV for NBTI is attributed to Si/IL and IL/HK interfaces; TG from DCIV for PBTI to IL/HK interface but at similar energy location as NBTI. TG from DCIV shows similar stress bias (V G,STR ), time (t STR ) and temperature (T) dependence for NBTI and PBTI, while TG for PBTI from SILC shows very different dependence as it likely scans TG at different spatial and energetic locations. TG contribution to V T shift (ΔV T ) is compared to ΔV T from ultra-fast measurements. A compact model is used to predict overall BTI ΔV T considering uncorrelated contributions from independently measured TG and trapping (TP) in pre-existing and generated bulk traps. Impact of IL scaling on BTI and its underlying subcomponents are studied. Physical origins of different TG and TP processes have been identified using Density Functional Theory (DFT) simulations.

Numerical modeling is used to explain the origin of the large ON/OFF ratios, ultra-low leakage, and high ON current densities exhibited by BEOL-friendly Access Devices (AD) based on Cu-containing MIEC materials [1-5]. Motion of large populations of copper ions and vacancies leads to exponential increases in hole current, with a turn-ON voltage that depends on material bandgap. Device simulations match experimental observations as a function of temperature, electrode aspect-ratio, thickness, and device CD.

Continued scaling of semiconductor devices in logic and memory applications requires the introduction of high-k (HK) dielectrics to enhance the capacitance density while maintaining a low leakage. Of particular concern in DRAM memory applications is the so called `dielectric relaxation current', which is significantly enhanced with HfO2 dielectrics as compared to SiO2. In this paper, it is shown that these relaxation currents arise from electron trapping/detrapping by/from oxygen vacancy defects in the HfO2 dielectric from/to the contact electrodes. This understanding is utilized to minimize `dielectric relaxation currents' by optimizing the defect structure in the HK dielectric. By creating trap-free dielectric films with N or La doping, we show that substantial reductions in the relaxation currents can be achieved. For the first time, it is demonstrated that a HK dielectric stack formed as a result of these treatments can have reduced relaxation currents similar to SiO2, thus providing a pathway to solving a fundamental paradigm associated with HK dielectrics that has persisted for several years.

Probing the internal 3D structure of label-free objects, such as biological cells and tissues in their natural environments, with nano-scale accuracy and sensitivity is of great importance in many biomedical applications. Using the 3D scattering potential description of an object's structure, we present the principle of spectral encoding of 3D spatial frequency (SESF) that encodes different spatial frequencies of the scattering potential into corresponding wavelengths. The SESF principle allows us to (1) perform real-time quantitative dominant-structure imaging of a label-free object. This imaging approach produces a color map in real time in which dominant axial spatial period (or frequency) at each image point is encoded as a corresponding spectral color. We demonstrate the efficacy of real-time imaging using model systems and show the potential of this technique to detect dominant structural changes in pre-cancerous cells that are not visible using conventional microscopy. (2) We extend the SESF principle to measure the entire axial spatial period distribution for each image point. Experimental results based on characterization of cell cycle phases are presented along with comparison with structural information extracted from TEM cell images. (3) Finally, we present spectral tomographic imaging (STI), a new SESF-based integrated tomographic approach that is able to simultaneously reconstruct the 3D object with sub-micron resolution, and also provide spatially-resolved characterization of its structure that has the ability to construct local axial spatial period distribution for any 3D sub-region of interest within the object. Simulation-based examples are presented. In all three cases structural characterization is achieved with nanoscale sensitivity and accuracy.

The 4ÃÂ4 discrete cosine transform is one of the most important building blocks for the emerging video coding standard, viz. H.264. The conventional implementation does some approximation to the transform matrix elements to facilitate integer arithmetic, for which hardware is suitably prepared. Though the transform coding does not involve any multiplications, quantization process requires sixteen 16-bit multiplications. The algorithm used here eliminates the process of approximation in transform coding and multiplication in the quantization process, by usage of algebraic integer coding. We propose an area-efficient implementation of the transform and quantization blocks based on the algebraic integer coding. The designs were synthesized with 90 nm TSMC CMOS technology and were also implemented on a Xilinx FPGA. The gate counts and throughput achievable in this case are 7000 and 125 Msamples/sec.

This paper presents the architecture and the VHDL design of an integer 2-D DCT used in the H.264/AVC. The 2-D DCT computation is performed by exploiting it’s orthogonality and separability property. The symmetry of the forward and inverse transform is used in this implementation. To reduce the computation overhead for the addition, subtraction and multiplication operations, we analyze the suitability of carry-free position independent residue number system (RNS) for the implementation of 2-D DCT. The implementation has been carried out in VHDL for Altera FPGA. We used the negative number representation in RNS, bit width analysis of the transforms and dedicated registers present in the Logic element of the FPGA to optimize the area. The complexity and efficiency analysis show that the proposed architecture could provide higher through-put.

Maximum likelihood (ML) and Maximum a-posteriori (MAP) are the most widely used algorithms for emission tomography (ET). MAP-approach heavily depends on Gibbs hyperparameter for noise free reconstruction. Choosing a correct hyperparameter is difficult and time consuming task. Recently proposed median root prior (MRP) algorithm is a good alternative, but are prone to step like streaking effect. In this research work, a fuzzy logic based approach is proposed to overcome these shortcomings. Unlike traditional potential function, a fuzzy potential is used for modeling inter pixel interaction. Two basic operations viz. edge detection and fuzzy smoothing are performed sequentially during each iteration. The first operation is employed for the detection of edges (if present) in all the eight directions of a 3 x 3 neighborhood window. The second operation uses this edge information to perform fuzzy smoothing. Due to recursive nature of the reconstruction algorithm, both these operations are employed iteratively to reduce heavy noise produced due to dimensional instability [10]. Simulated experimental results are obtained to show the feasibility of the proposed approach. These algorithms are also compared with other approaches such as, MAP and MRP by numerical measures and visual inspection. Algorithm evaluation shows promising results.

Maximum a-posteriori (MAP) estimation has the advantage of incorporating prior knowledge in the image reconstruction procedure which makes it a superior estimation technique compared to convolution back-projection (CBP), maximum likelihood (ML) etc. The inclusion of prior knowledge greatly improves the image quality. Howevel; ex- cess smoothening occurs as the MAP-iterations are continued. In biomedical imaging sharp reconstruction is oj potential use. To meet these requirements a new prior is proposed which is capable of enhancing the edges by recognizing the correlated neighbors while restoring homogeneity in the uniform regions of the reconstruction. The proposed prior serves as a post-processing technique in Bayesiari domain, once an approxirnate smooth reconstruction is generated by MAP-algorithm. Simulated experiments show improved sharp reconstruction with the proposed post-processing technique.

The expectation maximization (EM) algorithm is extensively used for tomographic image reconstruction based on positron emission tomography (PET) modality. The EM algorithm gives good reconstructed images compared to those created by deterministic methods such as filtered back projection (FBP) and convolution back projection (CBP). However, the computational complexity of EM-based algorithm is high due to the iterative nature of the algorithm. Prior knowledge of the estimate has been added to the basic EM algorithm to improve image quality as well as to reduce the number of iterations required for an acceptable image quality. We have developed an algorithm which produces better quality images in much lesser number of iterations, thereby speeding up the image reconstruction task.