As the integration density and capacitance of semiconductor devices have increased, high-dielectric (High-k) materials have attracted considerable attention. We investigated the dependence of threshold voltage (Vth) characteristics of the High-k/Metal Gate MOSFET fabricated with 65 nm CMOS process on the temperature, in comparison to conventional SiON/Poly-Si Gate MOSFET. Two aspects including the Fermi level and the channel mobility in MOSFET are discussed in details. Furthermore, the influence of threshold voltage characteristics of the High-k/Metal Gate MOSFET on the logic threshold voltage (Vth-inv) of CMOS inverter is reported in this paper.

Resistive switching of metal-insulator-metal (MIM), consisting of a metal-organic chemical vapour deposition (MOCVD) TiO2 layer sandwiched between Pt electrodes, has been measured systematically before and after thermal annealing in different ambiences. With H2 annealing at 400, the current level in the high-resistive state (HRS) significantly decreased while little change in the low-resistive state (LRS) was observed. As a result, the switching ratio over 7 orders of magnitude at the current level was obtained. From the analysis of current-voltage (I-V) characteristics in HRS and LRS, we found that the LRS was characterized with an ohmic conduction, while in the HRS after H2 annealing, charge trapping became significant as a result of a significant decrease in the current level. In a separate experiment, a partial reduction in TiO2 was detected using high-resolution X-ray photoelectron spectroscopy (XPS) after resistant-state switching from HRS to LRS by using a Hg probe as a top electrode, which is associated with filament formation.

We studied the interaction of Bis-diethylaminosilane (SiH2[N(C2H5)2]2, BDEAS) with a hydroxylized Si (001) surface for SiO2 thin-film growth using density functional theory (DFT). BDEAS was adsorbed on the Si surface and reacted with the H atom of hydroxyl (-OH) to produce the di-ethylaminosilane (-SiH2[N(C2H5)2], DEAS) group and di-ethylamine (NH(C2H5)2, DEA). Then, DEAS was able to react with another H atom of -OH to produce DEA and to form the O-(SiH2)-O bond at the inter-dimer, inter-row, or intra-dimer site. Among the three different sites, the intra-dimer site was the most probable when it came to forming the O-(SiH2)-O bond.

We propose the collective electron tunneling model in the electron injection process between the Nano Dots (NDs) and the two-dimensional electron gas (2DEG). We report the collective motion of electrons between the 2DEG and the NDs based on the measurement of the Si-ND floating gate structure in the previous studies. However, the origin of this collective motion has not been revealed yet. We evaluate the proposed tunneling model by the model calculation. We reveal that our proposed model reproduces the collective motion of electrons. The insight obtained by our model shows new viewpoints for designing future nano-electronic devices.

Recently, the 3-dimensional (3-D) vertical Floating Gate (FG) type NAND flash memory cell arrays with the Extended Sidewall Control Gate (ESCG) was proposed [7]. Using this novel structure, we successfully implemented superior program speed, read current, and less interference characteristics, by the high Control Gate (CG) coupling ratio with less interference capacitance and highly electrical inverted S/D technique. However, the process stability of the ESCG structure has not been sufficiently confirmed such as the variations of the physical dimensions. In this paper, we intensively investigated the electrical dependency according to the physical dimensions of ESCG, such as the line and spacing of ESCG and the thickness of barrier oxide. Using the 2-dimentional (2-D) TCAD simulations, we compared the basic characteristics of the FG type flash cell operation, in the aspect of program speed, read current, and interference effect. Finally, we check the process window and suggest the optimum target of the ESCG structure for reliable flash cell operation. From above all, we confirmed that this 3-dimensional vertical FG NAND flash memory cell arrays using the ESCG structure is the most attractive candidate for terabit 3-D vertical NAND flash cell array.

In this paper, we propose a spatially adaptive gradient-projection algorithm for the H.264 video coding standard to remove coding artifacts using local statistics. A hybrid method combining a new weighted constrained least squares (WCLS) approach and the projection onto convex sets (POCS) approach is introduced, where weighting components are determined on the basis of the human visual system (HVS) and projection set is defined by the difference between adjacent pixels and the quantization index (QI). A new visual function is defined to determine the weighting matrices controlling the degree of global smoothness, and a projection set is used to obtain a solution satisfying local smoothing constraints, so that the coding artifacts such as blocking and ringing artifacts can be simultaneously removed. The experimental results show the capability and efficiency of the proposed algorithm.

We have investigated the effect of deoxyribonucleic acid (DNA) adsorption on a graphene field-effect-transistor (FET) device. We have used graphene which is grown on a Ni substrate by chemical vapour deposition. The Raman spectra of our graphene indicate its high quality, and also show that it consists of only a few layers. The current-voltage characteristics of our bare graphene strip FET show a hole conduction behavior, and the gate sensitivity of 0.0034 µA/V, which is reasonable with the size of the strip (510 µm2). After the adsorption of 30 base pairs single-stranded poly (dT) DNA molecules, the conductance and gate operation of the graphene FET exhibit almost 11% and 18% decrease from those of the bare graphene FET device. The observed change may suggest a large sensitivity for a small enough (nm size) graphene strip with larger semiconducting property.

In order to reduce PtSi Schottky barrier height (SBH) for electron, we investigated modulation of PtSi work function by alloying with low work function metal, such as Hf (3.9 eV) and Yb (2.7 eV). Pt (10-20 nm)/Hf, Yb (0-10 nm)/n-Si(100) stacked structures were in-situ deposited at room temperature by RF magnetron sputtering method. In case of PtxHf1 - xSi formed at 400/60 min annealing in N2, SBH for electron was reduced from 0.85 eV to 0.53 eV with Hf thickness without increase of sheet resistance. Yb incorporation also affected the SBH modulation, however, the sheet resistance increased with increase of Yb thickness.

This paper discusses the possibility of deploying a short-range cognitive radio (secondary communication system) within the service area of a primary system. Although the secondary system interferes with the primary system, there are certain locations in the service area of the primary system where the cognitive radio can reuse the frequency of the primary system without causing harmful interference to it and being disturbed by the primary system. These locations are referred to as having a spatial opportunity for communications in the secondary system, since it can reuse the frequency of the primary system. Simulation results indicate that the antenna gain, beamwidth, and propagation path loss greatly affect the spatial opportunity of frequency reuse for the secondary users. The results show that spatial spectrum reuse can be significantly increased when the primary system users are equipped with directional antennas. An important component in this study is the heterogeneous path loss model, i.e., the path loss model within the primary system is different from the model used to calculate the interference between the primary and the secondary systems. Our results show that the propagation models corresponding to the actual antenna heights in the primary/secondary system can largely impact the possibilities for spectrum reuse by the cognitive radios.

A zig-zag Gardner algorithm with parallel architecture is presented in this letter. This algorithm performs timing adjustment in each individual burst independently for high speed wireless burst communication with a short guard. Over sampling data are stored in RAM initially and read forward and backward alternately later. The proposed algorithm has distinct symmetric characteristic in the forward and backward process, which makes the alternate sequences achieve nearly the same effect as a continuous sequence. The performance of the proposed algorithm is very close to the theoretical curve.

Vehicle routing is an important combinatorial optimization problem. In real transport networks,the travel speed and travel time of roads have large time-variability and randomness. The study of vehicle routing problem in time-dependent network has even more practical value than static network VRP problem. This paper combines the features of time-dependent networks and gives the mathematical models of the time-dependent vehicle routing problem. On this basis, the traditional ant colony optimization algorithm is improved. A new path transfer strategy of ants and new dynamic pheromone update strategy applicable to time-dependent network are proposed. Based on these strategies, the improved ant colony algorithm is given for solving the vehicle routing problem in time-dependent networks. The simulation results show that the algorithm can effectively solve the vehicle routing problem in time-dependent network and has better computational efficiency and convergence speed.

This paper introduces an interactive expression editing system that allows users to design facial expressions easily. Currently, popular example-based methods construct face models based on the examples of target face. The shortcoming of these methods is that they cannot create expressions for novel faces: target faces not previously recorded in the database. We propose a solution to overcome this limitation. We present an interactive facial-geometric-feature animation system for generating expressions of novel faces. Our system is easy to use. By click-dragging control points on the target face, on the computer screen display, unique expressions are generated automatically. To guarantee natural animation results, our animation model employs prior knowledge based on various individuals' expressions. One model prior is learned from motion vector fields to guarantee effective facial motions. Another, different, model prior is learned from facial shape space to ensure the result has a real facial shape. Interactive animation problem is formulated in a maximum a posterior (MAP) framework to search for optimal results by combining the priors with user-defined constraints. We give an extension of the Motion Propagation (MP) algorithm to infer facial motions for novel target faces from a subset of the control points. Experimental results on different facial animations demonstrate the effectiveness of the proposed method. Moreover, one application of our system is exhibited in this paper, where users create expressions for facial sketches interactively.

In this article, we present a new image-stabilization technology for still images based on blind deconvolution and introduce it to a consumer digital still camera. This technology consists of three features: (1)double-exposure-based PSF detection, (2)efficient image deblurring filter, and (3)edge-based ringing reduction. Without deteriorating the deblurring performance, the new technology allows us to reduce processing time and ringing artifacts, both of which are common problems in image deconvolution.

Energy conservation is an important issue in mobile ad hoc networks (MANET), where the terminals are always supplied with limited energy. A new routing protocol is presented according to the study on the influence of low-energy nodes in ad hoc networks. The novel routing protocol (energy sensing routing protocol, ESRP) is based on the energy sensing strategy. Multiple strategy routing and substitute routing are both adopted in this paper. Referring to the level of the residual energy and the situation of energy consumption, different routes are chosen for packets transmission. The local maintenance is adopted, which can reduce packets retransmission effectively when the link breaks. We focus on the network lifetime most in all performances. The evaluation is done in comparison with other routing protocols on NS2 platform, and the simulation results show that this routing protocol can prolong the network lifetime and balance energy consumption effectively.

This paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem.

The aggregate throughput of wireless mesh networks (WMNs) can be significantly improved by equipping the mesh routers with multiple radios tuned to orthogonal channels. Not only the links using orthogonal channels can be activated at a time, but some links in the same channel also can be activated concurrently if the Signal-to-Interference-and-Noise Ratio (SINR) at their receivers is not lower than the threshold, which is the spatial-reuse characteristic. STDMA is considered as one of the medium access schemes that can exploit spatial reuse to improve network throughput. Past studies have shown that optimizing the performance of STDMA is NP-Hard. Therefore, we propose a STDMA-based scheduling algorithm that operates in a greedy fashion for WMNs. We show that the proposed algorithm enhances not only the throughput but also the fairness by capturing the essence of spatial-reuse approach of STDMA and giving medium access opportunities to each network element based on its priority. We furthermore validate our algorithm through theoretical analysis and extensive simulations and the results show that our algorithm can outperform state-of-the-art alternatives.

We provide a BER analysis of the well-known rotation code, which has been applied to various transmission schemes, such as coordinate-interleaved design (CID) for space-time block codes and trans-modulation or constellation rearrangement for a cooperative relay system. An upper bound on the BER of the rotation code under a fading channel is derived. It turns out to be much tighter than the existing one, which relies on the Chernoff bound. More specifically, the proposed bound is virtually identical to simulation result when Eb/No is larger than 4 dB.

In this paper, we compare 1/f noise characteristics of High-k/Metal Gate MOSFET and SiON/Poly-Si Gate MOSFET experimentally, and evaluate the time fluctuation of drive current. These MOSFETs are fabricated with 65 nm CMOS process, and their gate lengths (Lg) are 130 nm. Specifically, we focus on the dependency of the time fluctuation of drive current on channel width (W) and temperature (T). First, we evaluate the dependency on channel width. In the case of SiON/Poly-Si Gate MOSFET, when the channel width is narrow such as W=200 nm and W=250 nm, Power Spectrum Density (PSD) depends on 1/f2 at two frequency regions. Moreover, as the channel width is wide such as W=300 nm, W=500 nm and W=1000 nm, PSD depends on 1/f and the value of PSD shifts lower. This is a new phenomena observed for the first time. On the other hand, in the case of High-k/Metal Gate MOSFET, the value of PSD is about 100 times larger than that of SiON/Poly-Si Gate MOSFET. Moreover, there is no dependency of PSD on channel width ranges from 150 nm to 1000 nm. Second, we evaluate the dependency on temperature. In the case of SiON/Poly-Si Gate MOSFET, when the temperature (T) is lowered from T=27 to T=-35, the dependency changes from the 1/f dependency to the 1/f2 dependency at two different frequency regions. This is also a new phenomena observed for the first time. However, in the case of High-k/Metal Gate MOSFET, there is no dependency of PSD on temperature ranges from 27 to -35. These results are useful knowledge for designing future LSI, because PSD dependency shows different characteristics when both channel width and temperature are changed.

Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) is considered as a promising equalization technique for a broadband single-carrier (SC) transmission. When a square-root Nyquist filter is used at a transmitter and receiver to limit the signal bandwidth, the presence of timing offset produces the inter-symbol interference (ISI) and degrades the bit error rate (BER) performance using MMSE-FDE. In this paper, we discuss the mechanism of the BER performance degradation in the presence of timing offset. Then, we propose joint MMSE-FDE & spectrum combining which can make use the excess bandwidth introduced by transmit filter to achieve larger frequency diversity gain while suppressing the negative effect of the timing offset.

In this paper, a 24 GHz frequency source for low phase noise is presented in a 0.18 µm CMOS process. The 24 GHz frequency source chip is composed of a 12 GHz voltage controlled oscillator (VCO) and a 24 GHz balanced frequency doubler with class B gate bias. Compared to a conventional complementary VCO, the proposed 12 GHz VCO has phase noise improvement by using resistor current sources and substituting the nMOS cross-coupled pair in the conventional complementary VCO for a gm-boosted nMOS differential Colpitts pair. The measured phase noise and fundamental frequency suppression are -107.17 dBc/Hz at a 1 MHz offset frequency and -20.95 dB at 23.19 GHz frequency, respectively. The measured frequency tuning range is from 23.19 GHz to 24.76 GHz drawing 2.72 mA at a supply voltage of 1.8 V not including an output buffer.