bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplified Spontaneous Emission from the Monomer of a Conjugate Polymer by Energy Transfer Process
Authors: AlSalhi Mohamad
Published: March 2010

Conjugate polymers are recognized as remarkable optically pumped laser media. Their spectral and laser characteristics are similar to those of dye laser media, but they are superior in performance. In this study, amplified spontaneous emission (ASE) has been obtained from two sets of solutions, one containing Coumarin 485 (C485) as a donor and poly[2-methoxy-5-(20-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) as an acceptor and another containing MEH-PPV as a donor and laser dye 700 (LD 700) as an acceptor. A high power neodymium-doped yttrium aluminium garnet (Nd:YAG) laser at 355 nm produces the excitation of these laser media. Depending upon the concentration and pump energy, ASE was obtained at 485 nm from C485, at 700 nm from LD 700, or at 600 nm from the MEH-PPV aggregate, or at 560 nm from the unaggregated, monomeric form of MEH-PPV or a combination of the above. The ASE spectra give new insight into the excited-state dynamics of these conjugate polymers. This study shows that the energy transfer interaction is necessary for obtaining laser action from the unaggregated MEH-PPV.
Erbium-Doped All-Fiber Green Up-Conversion Amplified Emission in Silica-Based Fiber System
Authors: Tsao Hong-Xi , Lin Shih-Ting , Su Hsin-Chia , Horng Ji-Bin , Sheu Jinn-Kong
Published: March 2010

All-fiber 546-nm-wavelength green up-conversion amplified emission using an erbium-doped silica fiber at room temperature is demonstrated. Silica fiber is known for its high phonon energy and high nonradiative relaxation rate that prevents up-conversion lasing. In this study, we design an all-fiber system without using a free-space device to generate amplified emission. We use a 975 nm high power diode pump laser, a 25-m-long double-cladding erbium-doped silica fiber, and two specially designed fiber-type end-face reflectors to generate 270 µW, 546 nm green amplified emission. It was found that the high power density inside the double-cladding fiber makes up-conversion lasing possible by overcoming the population inversion.
Numerical Investigation of Method of Reconstructing Gain-Switched Picosecond Pulses from Laser Diodes without Autocorrelation Measurements
Authors: Wada Kenji , Matsuyama Tetsuya , Noritake Daisuke , Fukui Hidetoshi , Koyama Shinji , Horinaka Hiromichi
Published: March 2010

A simple method for characterizing the amplitude and phase of picosecond optical pulses from gain-switched laser diodes without autocorrelation measurements is proposed, based on an iterative calculation using only the fundamental and second-harmonic power spectra of an optical pulse to be estimated. The feasibility of the proposed method is examined numerically for gain-switched picosecond pulses obtained using single-mode laser diode rate equations. As a result, although the lack of information normally obtained from autocorrelation measurements means that the initial conditions have a strong influence on the iterative calculation, the proposed method was found to correctly reconstruct the waveform and the frequency-chirp of gain-switched picosecond pulses with an accuracy close to that of the conventional method incorporating autocorrelation measurements.
Carrier-Envelope Phase Control of Few-Cycle Parametric Chirped-Pulse Amplifier
Authors: Adachi Shunsuke , Ishii Nobuhisa , Kobayashi Yohei , Nomura Yutaka , Itatani Jiro , Kanai Teruto , Watanabe Shuntaro
Published: March 2010

We demonstrate the carrier-envelope phase (CEP) stabilization of the 5-fs, multi-mJ parametric chirped-pulse amplification system. The slow CEP drift induced in the parametric chirped-pulse amplifier was precompensated in the phase-control loop of the seed oscillator, and arbitrary CEP control of the whole system was realized over a few hours. We discuss several possible origins that induce CEP noise of the amplified pulses.
Deconvolution of Transmission Mössbauer Spectra Using Conjugate Gradient Method
Authors: Kato Ryuji , Tamada Yoshinori , Ono Teruo , Nasu Saburo
Published: March 2010

A numerical method to extract the absorber resonance cross-section from the transmission Mössbauer spectrum has been presented. The convolution equation which relates to both of the transmission spectrum and the cross-section is expressed by linear algebraic equation and solved by conjugate gradient method. Applying this method to the examples simulated numerically, the resonance cross-section spectra have been successfully reproduced. Present method is powerful to determine the intensities and their ratios of the absorption lines. The effects due to the statistical fluctuations of the data and the non-resonant radiation have been also discussed.
Tunable Microwave Filters and Phase Shifters Based on Ferromagnetic/Dielectric Multilayer Waveguides
Authors: Zhang Jiashu , Zhao Jinzhu , Peng Ruwen , Li Jia , Zhang Ruili , Wang Mu
Published: March 2010

We present theoretically microwave filters and phase shifters based on the propagation of hybrid electromagnetic-spin waves in a ferromagnetic/dielectric multilayer waveguide. It is demonstrated that some propagating modes of microwave appear in the waveguide and the number of the modes increases with increasing the number of the building blocks. Those propagating modes originate from the coupling between microwave and spin wave, associated with the collective excitations of spin motions in the whole multilayer system when the layer thickness is relatively thin. In addition, it is shown that the attenuation of microwaves and phase difference in the waveguide are tuned by the magnetic field, the ferromagnetic resonance line width, and the conductivity of ferromagnetic material. The investigations can be used in designing tunable compact bandpass filters and phase shifters of microwave.
Quantum Mechanical Effects on the Threshold Voltage of Double-Gate Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Hu Guang-Xi , Liu Ran , Qiu Zhi-Jun , Wang Ling-Li , Tang Ting-Ao
Published: March 2010

A model for a metal–oxide–semiconductor field-effect transistor (MOSFET) with a double gate (DG) is developed. Quantum mechanical effects on the threshold voltage (V
TH) are modeled and investigated analytically. The analytic model shows how V
TH is increased with quantum mechanical effect. The model is applicable to both symmetric DG (SDG) and asymmetric DG (ADG) nMOSFETs, and is also applicable to both doped and undoped DG nMOSFETs. The analytic results are verified by comparing with the results obtained from simulations using Schred, and good agreement is observed. The V
TH of an ADG nMOSFET will shift more than that of an SDG nMOSFET, and the V
TH of a DG transistor with (110)-silicon (Si) orientation will shift more than that of a DG transistor with (100)-Si orientation. When the silicon thickness t
si < 3 nm, the V
TH shift will be significant, and one should be careful in the use of an extremely thin silicon body. When the body doping density (N
A) is not high (<1018 cm-3), the V
TH shift is almost the same for different N
A. When N
A > 1018 cm-3, the higher the N
A, the more the V
TH shift.
Evaluation of Refilled Channel Regions in 4H-SiC Buried Gate Static Induction Transistors
Authors: Takatsuka Akio , Tanaka Yasunori , Yano Koji , Yatsuo Tsutomu , Arai Kazuo
Published: March 2010

We evaluated the crystalline quality of the channel region in silicon carbide buried gate static induction transistors (SiC-BGSITs) by transmission electron microscopy (TEM) and scanning spreading resistance microscopy (SSRM). TEM observations revealed that no crystalline defects were generated in the channel region of SiC-BGSITs during epitaxial regrowth in trenches. The SSRM result indicated that the refilled channel region had a spreading resistance distribution of about ten times due to a high noise resulting from contact resistance. This noise was so high that we could not detect carrier density distributions from SSRM signals. However, on the basis of the leakage current and blocking characteristics of the SiC-BGSITs, we confirmed that there was no serious carrier density distribution that affected the device operation in the channel region.
Effects of the AlN Interlayer on the Distribution and Mobility of Two-Dimensional Electron Gas in AlGaN/AlN/GaN Heterojunctions
Authors: Hu Weiguo , Ma Bei , Li Dabing , Miyagawa Reina , Miyake Hideto , Hiramatsu Kazumasa
Published: March 2010

Al0.25Ga0.75N/AlN/GaN heterojunctions with AlN interlayers of various thicknesses were grown on c-plane sapphire by metalorganic vapor phase epitaxy (MOVPE). We have revealed that the AlN interlayer hardly affects morphologies and crystal qualities; however, it prominently enhances the two-dimensional electron gas (2DEG) mobility. The optimum thickness of the AlN interlayer is 1 nm, and the corresponding room temperature Hall mobility and the sheet carrier density are 1700 cm2 V-1 s-1 and 1.27 ×1013 cm-2, respectively. Self-consistent calculation results indicates that with increasing AlN thickness, i) the conduction-band discontinuity between AlGaN and GaN linearly increases; ii) the percentage of the total carriers in the AlGaN layer exponentially decreases, and content in the AlN layer exponentially increases.
Local Density of States of Partially Oxidized Ag(110) Surfaces Observed Using Scanning Tunneling Microscope Light-Emission Spectroscopy
Authors: Uehara Yoichi , Ushioda Suketsue
Published: March 2010

We have observed the scanning tunneling microscope (STM) light-emission spectra of partially oxidized Ag(110) surfaces with atomic spatial resolution. The STM image visualized Ag–O chains along the [001] direction as light rows, separated by a distance n ×a from adjacent light rows. Here, n is an integer between 2 and 7, and a is the surface lattice constant of Ag in the [110] direction. The STM light-emission spectra were measured for tip locations over the light rows and the midpoints of the darkly imaged areas sandwiched by two adjacent light rows. While the spectral shapes of the STM light-emissions were identical, their amplitudes showed atomic-site dependence, i.e., the STM light-emission intensities showed atomic-site dependence without any spectral differences. The STM light-emission intensities at the midpoints of the dark areas increased with n. The STM light-emission intensities of the light rows were independent of the widths of the adjacent dark areas. The experimental results were analyzed by the dielectric theory of STM light-emission, and it was found that the observed atomic-site dependence is caused by electronic states localized along the light rows. These states are identified as the p
y
and p
z
surface bands induced by adsorbed oxygen.
Evaluation of Electron Energy Distribution Function in Microwave Discharge Plasmas by Spectroscopic Diagnostics with Collisional Radiative Model
Authors: Mizuochi Jun , Sakamoto Takeshi , Matsuura Haruaki , Akatsuka Hiroshi
Published: March 2010

The effect of the electron energy distribution function (EEDF) on the population distribution of excited states is investigated in He and Ar plasmas sustained by a 2.45 GHz microwave at a discharge pressure of 1–5 Torr. The EEDF is measured with a Langmuir probe by Druyvesteyn's method and used as the input parameter of the collisional-radiative (CR) model calculation. The calculated population density of the excited states is compared with the results of optical emission spectroscopic measurement. Reasonable agreement is found between them. It is also confirmed that the measured EEDFs was depleted at energies above the first excitation potential of the discharge gas atoms. When we assume a Maxwellian EEDF and calculate the population distribution of excited states of the argon plasma, we find a marked discrepancy between the populations of excited states observed experimentally and those calculated by the CR model, while a discrepancy for the helium plasma is also found but is less marked.
Gate Overlap Optimization and Performance Variation for Thin-Film Transistors with Source/Drain Edge Waviness
Authors: Jeong Jaewook , Hong Yongtaek
Published: March 2010

By using ATLAS three-dimensional (3D) device simulator, we analyzed influence of gate overlap (GO) between gate and source/drain (S/D) electrodes on channel current and parasitic resistance variations of bottom-gate staggered thin-film transistors (TFTs) with wavy edge S/D electrodes that are frequently observed due to printing process variation, especially for narrow line printing. Transmission line method (TLM) analysis was performed, and showed channel current variation had a significant dependency on gate overlap. As gate overlap increases, current flow becomes less localized around peaks of the wavy edge pattern, reducing parasitic resistance. However, reduction of parasitic resistance becomes saturated when gate overlap is greater than the lateral distance over which current is collected by the contact of the wavy edge TFT. This lateral distance was found to be smaller than peak-to-peak magnitude of the wavy patterns.
Line Edge Roughness Reduction Using Resist Reflow Process for 22 nm Node Extreme Ultraviolet Lithography
Authors: Cho In Wook , Kim Hyunsu , You Jee-Hye , Oh Hye-Keun
Published: March 2010

Extreme ultraviolet lithography (EUVL) has been developed and studied for a sub-22 nm semiconductor device. It is difficult to obtain a smooth sub-22 nm pattern because line edge roughness (LER) and linewidth roughness (LWR) cannot be controlled well. According to the 2008 ITRS roadmap, LER has to be below 1.3 nm to achieve a 22 nm node for EUVL. In our previous work, the resist reflow process (RRP), in which the resist is baked above the glass transition temperature (T
g), was very helpful for reducing LER and LWR for EUVL. LER and LWR could be decreased from ∼6 to ∼1 nm. As RRP time progresses, however, the critical dimension could become wider because the developed resist can flow more easily when the temperature is above T
g. Therefore, another method is suggested to solve this problem. The developed resist, which is intentionally designed with a 1:3 line and space (L/S) (11:33 nm) pattern, is baked above T
g. As a result, LER and LWR can be smoothed by RRP and we could achieve a 22 nm 1:1 L/S pattern with a small LER.
Evaluation of Damage Layer in an Organic Film with Irradiation of Energetic Ion Beams
Authors: Hada Masaki , Ibuki Sachi , Ninomiya Satoshi , Seki Toshio , Aoki Takaaki , Matsuo Jiro
Published: March 2010

We characterized the thickness and surface damage layer of poly(methyl metacrylate) (PMMA) organic films irradiated with Ar cluster or monomer ion beam using ellipsometry. A heavily damaged layer was detected on the surface of the PMMA film irradiated with Ar monomer ion beam; more than 2–3 nm of the surface were completely metamorphosed into a carbon-like layer and damage had accumulated with irradiation. On the other hand, no significant damage was detected on PMMA films irradiated with Ar cluster ion beams. These results corresponded with measurements of the irradiated surface by X-ray photoelectron spectroscopy (XPS). The sputtering depth from PMMA film irradiated with Ar cluster/monomer ion beams can also be measured using the ellipsometry method at nanometer-order resolution. The optical method of ellipsometry may be a desirable tool for sputtering yield measurement and surface damage layer estimation for organic films.
Effects of Si/Ni Composition Ratio of NixSiy Gate Electrode and Hf/Si Composition Ratio of Hf-Based High-k Insulator on Threshold Voltage Controllability and Mobility of Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Terai Masayuki , Hase Takashi , Shibahara Kentaro , Watanabe Hirohito
Published: March 2010

We have investigated the threshold voltage (V
T) controllability of metal–oxide–semiconductor field-effect transistors (MOSFETs) consisting of a Ni or Ni-full-silicide (Ni-FUSI) metal gate and a Hf-based high-k dielectric. We found that the Ni and Hf composition ratios in the metal electrode/HfSiON gate stacks are key factors for controlling the V
T and fixed charge in a HfSiON film. Decreasing the Si/Ni ratio of the gate electrode and the Hf/Si ratio of the gate dielectric relieved Fermi level pinning. Increasing the Hf/Si ratio increased the negative fixed charge in the film. In particular for HfO2, only the pure Ni electrode prevended Fermi level pinning. In the case of HfSiON whose Hf/Si ratio was 1.0, NiSi2 and NiSi phases were suitable for nFETs, and the Ni3Si phase and the pure Ni electrodes were suitable for pFETs. It was also found that the electron mobility of Ni-FUSI nFETs depended on the crystalline phase, while no marked degradation of hole mobility was observed in pFETs.
Planar Metal–Oxide–Semiconductor Field-Effect Transistors with Raised Source and Drain Extensions Fabricated by In situ Boron-Doped Selective Silicon Epitaxy
Authors: Kikuchi Yoshiaki , Tateshita Yasushi , Miyanami Yuki , Wakabayashi Hitoshi , Tagawa Yukio , Nagashima Naoki
Published: March 2010

Junction depth and parasitic resistance have a trade-off relationship. To improve this relationship, in situ boron-doped selective Si epitaxy was used to fabricate metal–oxide–semiconductor field-effect transistors (MOSFETs) with raised source and drain extensions and a facet. The amount of boron diffusion was small and the MOSFET also had low extension sheet resistance. Furthermore, with the optimization of four process parameters, spike rapid thermal annealing (RTA) temperature, halo dose, impurity concentration introduced by in situ doping, and epitaxial Si thickness, the relationship between the gate length at I
off=100 nA/µm and the drive current at I
off=100 nA/µm was improved.
Diffusion Control Using Matrix Change during Chemical Reaction for Inducing Anisotropic Diffusion in Chemically Amplified Resists
Authors: Kozawa Takahiro , Oizumi Hiroaki , Itani Toshiro , Tagawa Seiichi
Published: March 2010

The trade-off relationships between resolution, sensitivity, and line edge roughness (LER) are the most serious problems in the development of resist materials applicable to the mass production of semiconductor devices at 22 nm node and below. The improvement of efficiencies associated with resist pattern formation is required to simultaneously meet the requirements for the resolution, sensitivity, and LER. However, the improvement using conventional methods is physically limited and inadequate. In this study, the potential of anisotropic diffusion for ultrafine patterning was examined from the viewpoint of the feasibility of chemically amplified resists below the 22 nm node. A concept of diffusion control using the matrix change induced during catalytic chain reaction is strongly required in the design of next-generation resist materials for simultaneously meeting the resist requirements below the 22 nm node.
Magnification Embossed Radiography Utilizing Image-Shifting Subtraction Program
Authors: Osawa Akihiro , Watanabe Manabu , Sato Eiichi , Matsukiyo Hiroshi , Enomoto Toshiyuki , Nagao Jiro , Abderyim Purkhet , Aizawa Katsuo , Tanaka Etsuro , Mori Hidezo , Kawai Toshiaki , Ogawa Akira , Takahashi Kiyomi , Sato Shigehiro , Onagawa Jun
Published: March 2010

We developed an image-shifting subtraction program and carried out magnification embossed radiography (MER) utilizing single- and dual-energy subtractions. In particular, dual-energy subtraction was carried out to decrease the absorption contrast of unnecessary regions. The contrast resolution of the target region was increased by the use of subtraction software and a linear-contrast system in a flat-panel detector (FPD). The X-ray generator had a 100-µm-focus tube, and the subtractions were performed at tube voltages of 40 and 70 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. MER images with threefold magnification were obtained using the FPD with a pixel size of 48×48 µm2, and the shifting dimensions of the imaged object in the horizontal and vertical directions ranged from 48 to 192 µm. At a shifting distance ranging from 48 to 144 µm, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 50 µm. In the MER of nonliving animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in blood vessels, and iodine-based microspheres in coronary arteries of approximately 100 µm diameter.
Negative Oxide Charge in Thermally Oxidized Cr-Contaminated n-Type Silicon Wafers
Authors: Shimizu Hirofumi , Shimada Sadayoshi , Ikeda Masanori
Published: March 2010

The evaluation of thermally oxidized Cr-contaminated Si surfaces, by an AC surface photovoltage (SPV) method, indicates that a certain amount of contaminating Cr atoms resides in the SiO2 thin film, resulting in the creation of a negative oxide charge in the form of a (CrOSi)- and/or CrO2
- networks, which are postulated to be analogous to the (AlOSi)- network. For samples oxidized at temperatures between 550 and 700 °C for 10 min, the AC SPV gives evidence that the induced negative oxide charge causes a strongly inverted state of the Si surface. At oxidation temperatures higher than 700 °C and/or a longer oxidation time than 10 min, AC SPV is reduced, meaning that the strongly inverted state changes into a less depleted state, and finally, the AC SPV disappears. In this case, a collapse of the (CrOSi)- and/or CrO2
- networks is expected with a possible change into Cr2O3.
Double Self Quotient Image Based Image Flattening for Defect Detection in Thin Film Transistor Liquid Crystal Display Panel
Authors: Song Young-Chul , Kim Se-Yun , Park Kil-Houm
Published: March 2010

This paper presents the results of using self quotient image (SQI) to flatten the background region of a thin film transistor liquid crystal display image. To overcome an inherent shortcoming of SQI method, namely the halo effect in thin film transistor liquid crystal display images, double SQI method is introduced. Experimental results demonstrate that SQI can be used effectively to eliminate a non-uniformity of the background region in a test image.
Electroluminescence Analysis by Tilt Polish Technique of InP-Based Semiconductor Lasers
Authors: Ichikawa Hiroyuki , Sasaki Kouichi , Hamada Kotaro , Yamaguchi Akira
Published: March 2010

We developed an effective electroluminescence (EL) analysis method to specify the degraded region of InP-based semiconductor lasers. The EL analysis method is one of the most important methods for failure analysis. However, EL observation was difficult because opaque electrodes surround an active layer. A portion of each electrode had to be left intact for wiring to inject the current. Thus, we developed a partial polish technique for the bottom electrode. Tilt polish equipment with a rotating table was introduced; a flat polished surface and a sufficiently wide remaining portion of the bottom electrode were obtained. As a result, clear EL from the back surface of the laser was observed.
Effect of Pulsed Substrate Bias on Film Properties of SiO2 Deposited by Inductively Coupled Plasma Chemical Vapor Deposition
Authors: Hiramatsu Takahiro , Matsuda Tokiyoshi , Furuta Hiroshi , Nitta Hiroshi , Kawaharamura Toshiyuki , Li Chaoyang , Furuta Mamoru , Hirao Takashi
Published: March 2010

A high-quality SiO2 film was successfully achieved at a temperature of 150 °C by inductively coupled plasma chemical vapor deposition (ICP-CVD) with a bipolar pulsed bias applied to a substrate. When the SiO2 film was deposited without the pulsed substrate bias, its density rapidly decreased and its insulating property deteriorated. However, its densification was enhanced and its insulating property was improved by the pulsed substrate bias even though the deposition rate increased. A leakage current of less than 10.0 nA/cm2 and a breakdown voltage of 5.2 MV/cm at 1.0 µA/cm2 were obtained at a temperature of 150 °C with a deposition rate of 18.0 nm/min.
Reliability in Short-Channel p-Type Polycrystalline Silicon Thin-Film Transistor under High Gate and Drain Bias Stress
Authors: Choi Sung-Hwan , Kim Sun-Jae , Mo Yeon-Gon , Kim Hye-Dong , Han Min-Koo
Published: March 2010

We have investigated the electrical characteristics of short-channel p-type excimer laser annealed (ELA) polycrystalline silicon (poly-Si) thin-film transistors (TFTs) under high gate and drain bias stress. We found that the threshold voltage of short-channel TFTs was significantly shifted in the negative direction owing to high gate and drain bias stress (ΔV
TH = -2.08 V), whereas that of long-channel TFTs was rarely shifted in the negative direction (ΔV
TH = -0.10 V). This negative shift of threshold voltage in the short-channel TFT may be attributed to interface state generation near the source junction and deep trap state creation near the drain junction between the poly-Si film and the gate insulator layer. It was also found that the gate-to-drain capacitance (C
GD) characteristic of the stressed TFT severely stretched for the gate voltage below the flat band voltage V
FB. The effects of high gate and drain bias stress are related to hot-hole-induced donor like interface state generation. The transfer characteristics of the forward and reverse modes after the high gate and drain bias stress also indicate that the interface state generation at the gate insulator/channel interface occurred near the source junction region.
Lateral Growth of Polycrystalline Silicon–Germanium Thin Films Enhanced by Continuous-Wave Laser Crystallization
Authors: Hirose Kenta , Kobata Mitsunori , Sato Tadashi , Kitahara Kuninori , Hara Akito
Published: March 2010

The lateral crystallization of silicon–germanium (Si–Ge) thin films on glass substrates was carried out by using a continuous-wave laser. The Ge composition x and its distribution in the films were characterized by micro-Raman spectroscopy. Average x values in two films were observed to be 0.38 and 0.06, which were nearly equal to 0.41 and 0.05 obtained by X-ray photoelectron spectroscopy. Cellular structures with ridges were observed in certain parts of both films, many of which oriented along the laser scanning direction. The lengths of especially long cells were >100 µm. Twin and grain boundaries were observed along the top of a ridge and the bottom of a valley, respectively. The mapping of the Raman spectra indicated that Ge segregates toward the grain boundaries. The formation of directed cellular structures can be explained by the constitutional undercooling model that is characteristic of alloys. The addition of Ge to Si thin films was found to be useful for enhancing lateral growth in Si-related thin films on glass.
High Speed Six-Transistor Static Random Access Memory Cells Using Single Grain Thin Film Transistors Fabricated at Low Temperature Process
Authors: Golshani Negin , Derakhshandeh Jaber , Ishihara Ryoichi , Beenakker Cees I. M.
Published: March 2010

In this paper we will report successfully fabricated six transistor static random access memory (6T SRAM) cells using single-grain thin film transistors (TFTs). SRAM cells have been designed by analytical calculations and verified by DC and transient simulations. TFTs are fabricated by µ-Czochralski process that consists of making grain filter and Excimer laser crystallization at temperatures below 550 °C. The gate length of transistors are 2 µm. Fabricated SRAM cells based on single grain TFTs, show good read and write static noise margin (SNM and WNM) equal to 0.55 and 0.75 V at 3.3 V power supply, respectively. Finally, excellent read and write access times equal to 13 and 8 ns in 87 MHz worldline frequency were obtained.
Advanced Micro-Polycrystalline Silicon Films Formed by Blue-Multi-Laser-Diode Annealing
Authors: Noguchi Takashi , Chen Yi , Miyahira Tomoyuki , Mugiraneza Jean de Dieu , Ogino Yoshiaki , Iida Yasuhiro , Sahota Eiji , Terao Motoyasu
Published: March 2010

Semiconductor blue-multi-laser-diode annealing (BLDA) for amorphous Si film was performed to obtain a film containing uniform polycrystalline silicon (poly-Si) grains as a low temperature poly-Si (LTPS) process used for thin-film transistor (TFT). By adopting continuous wave (CW) mode at the 445 nm wavelength of the BLDA system, the light beam is efficiently absorbed into the thin amorphous silicon film of 50 nm thickness and can be crystallized stably. By adjusting simply the laser power below 6 W with controlled beam shape, the isotropic Si grains from uniform micro-grains to arbitral grain size of polycrystalline phase can be obtained with reproducible by fixing the scan speed at 500 mm/s. As a result of analysis using electron microscopy and atomic force microscopy (AFM), uniform distributed micro-poly-Si grains of smooth surface were observed at a power condition below 5 W and the preferred crystal orientation of (111) face was confirmed. As arbitral grain size can be obtained stably and reproducibly merely by controlling the laser power, BLDA is promising as a next-generation LTPS process for AM OLED panel including a system on glass (SoG).
Electrical Properties of Yttrium–Indium–Zinc-Oxide Thin Film Transistors Fabricated Using the Sol–Gel Process and Various Yttrium Compositions
Authors: Shin Hyun Soo , Kim Gun Hee , Jeong Woong Hee , Ahn Byung Du , Kim Hyun Jae
Published: March 2010

This study was the first to investigate the fabrication of yttrium–indium–zinc-oxide (YIZO) thin film transistors (TFTs) using the sol–gel process. YIZO thin films were made using various yttrium (Y) compositions from 10 to 20%. Thermogravimetry and differential scanning calorimetry (TG–DSC) data from the 15% Y sample revealed that the YIZO thin films crystallized above the temperature of 535 °C, much hotter than that of indium–gallium–zinc-oxide (IGZO) thin films. The best performance of YIZO TFTs was observed with a 15% ratio of Y to Zn: this yielded a saturation mobility of 1.12 cm2V-1s-1, an on/off ratio of 4.61×105, a threshold voltage of 0.54 V, and a subthreshold swing of 1.03 V/decade. This study also assessed the post-annealing temperature dependence of YIZO TFTs. The findings demonstrated the possibility of using Y to replace gallium (Ga), which has been used in previously reported solution-processed IGZO TFTs.
Voltage-Programming-Based Pixel Circuit to Compensate for Threshold Voltage and Mobility Using Natural Capacitance of Organic Light-Emitting Diode
Authors: Park Young-Ju , Jung Myoung-Hoon , Park Sang-Ho , Kim Ohyun
Published: March 2010

A voltage-programming-based pixel circuit with three thin-film transistors (TFTs) and one capacitor (3T1C) is proposed and simulated for active-matrix organic light-emitting diode (AMOLED) displays. Unlike the previously published voltage-programming pixel circuits, which only compensate for threshold voltage (V
T) unevenness, this circuit also compensates for mobility (µ) unevenness. OLEDs can be used not only as light-emitting devices but also as capacitors. This circuit uses the natural capacitance of OLEDs to compensate for the mobility unevenness. The Rensselaer Polytechnic Institute (RPI) model of smart simulation program with integrated circuit emphasis (SMART SPICE) is used to simulate the circuit. Moreover, we propose another pixel circuit that consists of three TFTs and two capacitors (3T2C). The additional capacitor allows control of the range of the data voltage of each color.
Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors
Authors: Kim Tae-Wook , Choi Byong-Deok
Published: March 2010

This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 µm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.
Simple Pixel Structure Using Video Data Correction Method for Nonuniform Electrical Characteristics of Polycrystalline Silicon Thin-Film Transistors and Differential Aging Phenomenon of Organic Light-Emitting Diodes
Authors: In Hai-Jung , Kwon Oh-Kyong
Published: March 2010

A simple pixel structure using a video data correction method is proposed to compensate for electrical characteristic variations of driving thin-film transistors (TFTs) and the degradation of organic light-emitting diodes (OLEDs) in active-matrix OLED (AMOLED) displays. The proposed method senses the electrical characteristic variations of TFTs and OLEDs and stores them in external memory. The nonuniform emission current of TFTs and the aging of OLEDs are corrected by modulating video data using the stored data. Experimental results show that the emission current error due to electrical characteristic variation of driving TFTs is in the range from -63.1 to 61.4% without compensation, but is decreased to the range from -1.9 to 1.9% with the proposed correction method. The luminance error due to the degradation of an OLED is less than 1.8% when the proposed correction method is used for a 50% degraded OLED.
Pixel Circuit for Organic Light-Emitting Diode-on-Silicon Microdisplays Using the Source Follower Structure
Authors: Kim Hyuk , Kwak Bong-Choon , Lim Han-Sin , Kwon Oh-Kyong
Published: March 2010

In this paper, we propose a new pixel circuit for organic light-emitting diode-on-silicon (OLEDoS) microdisplays. The proposed pixel circuit is composed of only two metal oxide semiconductor field-effect transistors (MOSFETs) and one capacitor in order to integrate the pixel circuit into the restricted pixel area (12.6×4.2 µm2). The proposed pixel circuit has a source follower structure that can control an extremely low emission current. The measured results show that the maximum deviation in the emission current of the proposed pixel circuit occurs at the highest gray level of 6 bits. The deviations in the measured emission current range from -0.9 least significant bit (LSB) to +1.0 LSB among 8 pixels.
Advances in Analysis of Longitudinal Data
Authors: Gibbons Robert D. , Hedeker Donald , DuToit Stephen
Published: March 2010

In this review, we explore recent developments in the area of linear and nonlinear generalized mixed-effects regression models and various alternatives, including generalized estimating equations for analysis of longitudinal data. Methods are described for continuous and normally distributed as well as categorical (binary, ordinal, nominal) and count (Poisson) variables. Extensions of the model to three and four levels of clustering, multivariate outcomes, and incorporation of design weights are also described. Linear and nonlinear models are illustrated using an example involving a study of the relationship between mood and smoking.
Behavioral Treatments in Autism Spectrum Disorder: What Do We Know?
Authors: Vismara Laurie A. , Rogers Sally J.
Published: March 2010

Although there are a large and growing number of scientifically questionable treatments available for children with autism spectrum disorder (ASD), intervention programs applying the scientific teaching principles of applied behavior analysis (ABA) have been identified as the treatment of choice. The following article provides a selective review of ABA intervention approaches, some of which are designed as comprehensive programs that aim to address all developmental areas of need, whereas others are skills based or directed toward a more circumscribed, specific set of goals. However, both types of approaches have been shown to be effective in improving communication, social skills, and management of problem behavior for children with ASD. Implications of these findings are discussed in relation to critical areas of research that have yet to be fully explored.
Personality Assessment from the Nineteenth to the Early Twenty-First Century: Past Achievements and Contemporary Challenges
Authors: Butcher James N.
Published: March 2010

The historical basis of personality assessment that led to the development of today's approaches and applications is described. The modern era of personality assessment began in late nineteenth-century Europe. Early twentieth-century highlights included the development of projective techniques like the Rorschach and several early self-report inventories, culminating in the development of the most widely used measure, the Minnesota Multiphasic Personality Inventory (MMPI). The most recent 30-year period showed expansions into personnel screening; clinical assessment, including wide use in forensic settings; and therapeutic assessment. However, contemporary controversies are apparent with two of the most widely used measures, the Rorschach and the MMPI instruments. These controversies are described, including concerns about the Exner Comprehensive System for the Rorschach and the last five years of changes to the MMPI-2, including the introduction of the Restructured Clinical (RC) Scales, the adoption of the Fake Bad Scale (FBS) into the instrument, and the release of the MMPI-2 Restructured Form (MMPI-2-RF). Current challenges facing psychologists in personality assessment are highlighted.
Update on Harm-Reduction Policy and Intervention Research
Authors: Marlatt G. Alan , Witkiewitz Katie
Published: March 2010

Harm reduction is a pragmatic approach to reduce the harmful consequences of alcohol and drug use or other high-risk activities by incorporating several strategies that cut across the spectrum from safer use to managed use to abstinence. The primary goal of most harm-reduction approaches is to meet individuals “where they are at” and not to ignore or condemn the harmful behaviors but rather to work with the individual or community to minimize the harmful effects of a given behavior. The current review addresses some of the newest developments with respect to harm-reduction policy, prevention, and treatment. In particular, this review highlights policies and programs that have been evaluated in peer-reviewed journals and shown to be effective at reducing the harms associated with alcohol and drug use. The overall goal of this review is to present some of the most recent developments in the field of harm reduction.
Substance Use Disorders: Realizing the Promise of Pharmacogenomics and Personalized Medicine
Authors: Hutchison Kent E.
Published: March 2010

Current pharmacological and psychosocial approaches to the treatment of alcohol dependence may best be described as modestly effective, and it is unlikely that a magic bullet for the treatment of any substance use disorder will ever be developed. Rather, it seems more likely that there will be a number of treatment options, each of which will target different mechanisms. Thus, future treatment gains are likely to depend on the ability to match individuals with the treatment most likely to benefit them, which in turn is contingent on our ability to understand the mechanisms that drive the maintenance of substance use disorders on an individual level. On a more global scale, this type of effort has been described as “personalized medicine” and has focused largely on the human genome as a source of information that can be used to match individuals to treatments. This review enumerates barriers to realizing the potential of personalized medicine for substance use disorders and identifies opportunities to overcome those barriers, which involve the development of translational approaches that focus on the development of brain-based phenotypes that serve as the target of both treatment development and of genetic research.
Successful Aging: Focus on Cognitive and Emotional Health
Authors: Depp Colin , Vahia Ipsit V. , Jeste Dilip
Published: March 2010

We review the definitions, predictors, and biobehavioral determinants of successful aging, as well as the evidence for and mechanisms of underlying selected interventions to enhance cognitive and emotional health in older adults. Defining successful aging has proven difficult, with discrepancies seen among biomedical, psychological, and lay perspectives. Although consensus is lacking, a number of studies have examined the genetic, lifestyle, and social determinants of operationalized determinants of successful aging; qualitative examinations of the meaning of the construct have also been conducted. The determinants coincide with fundamental aspects of aging. Recent clinical trials suggest that caloric restriction, physical activity, cognitive intervention, stress reduction, and social programs may enhance cognitive and emotional health in older people.
The Admissibility of Behavioral Science Evidence in the Courtroom: The Translation of Legal to Scientific Concepts and Back
Authors: Faust David , Grimm Paul W. , Ahern David C. , Sokolik Mark
Published: March 2010

Starting with the Daubert case, courtroom rules and guides regulating the admissibility of scientific evidence have undergone major revisions over the past 10 to 15 years. We review these changes and current legal rules and guides, in particular their impact on the admission of behavioral sciences evidence and testimony. We examine commonly intended meanings, conceptualizations, and language use relating to science and the admission of evidence within the legal system and their relation to more familiar terms and concepts within the behavioral sciences, identifying points of continuity and discontinuity. We then review illustrative legal cases involving challenges to the admission of psychological and psychiatric evidence and their implications for mental health professionals. Finally, we offer a framework for conceptualizing and prioritizing key legal criteria for determining admissibility and appraising standing on these factors within the mental health field. Increased mutual understanding between psychology and law should further enhance productive interfaces between the disciplines and add to the many instances in which the proper use of science in the courtroom has facilitated fair resolution of legal conflicts.
The Diagnosis of Mental Disorders: The Problem of Reification
Authors: Hyman Steven E.
Published: March 2010

A pressing need for interrater reliability in the diagnosis of mental disorders emerged during the mid-twentieth century, prompted in part by the development of diverse new treatments. The Diagnostic and Statistical Manual of Mental Disorders (DSM), third edition answered this need by introducing operationalized diagnostic criteria that were field-tested for interrater reliability. Unfortunately, the focus on reliability came at a time when the scientific understanding of mental disorders was embryonic and could not yield valid disease definitions. Based on accreting problems with the current DSM-fourth edition (DSM-IV) classification, it is apparent that validity will not be achieved simply by refining criteria for existing disorders or by the addition of new disorders. Yet DSM-IV diagnostic criteria dominate thinking about mental disorders in clinical practice, research, treatment development, and law. As a result, the modern DSM system, intended to create a shared language, also creates epistemic blinders that impede progress toward valid diagnoses. Insights that are beginning to emerge from psychology, neuroscience, and genetics suggest possible strategies for moving forward.
Increased ANG II sensitivity following recovery from acute kidney injury: role of oxidant stress in skeletal muscle resistance arteries
Authors: Phillips Shane A. , Pechman Kimberly R. , Leonard Ellen C. , Friedrich Jessica L. , Bian Jing-Tan , Beal Alisa G. , Basile David P.
Published: March 2010

Ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) results in prolonged impairment of peripheral (i.e., nonrenal) vascular function since skeletal muscle resistance arteries derived from rats 5 wk post-I/R injury, show enhanced responses to ANG II stimulation but not other constrictors. Because vascular superoxide increases ANG II sensitivity, we hypothesized that peripheral responsiveness following recovery from AKI was attributable to vascular oxidant stress. Gracilis arteries (GA) isolated from post-I/R rats (∼5 wk recovery) showed significantly greater superoxide levels relative to sham-operated controls, as detected by dihydroeithidium, which was further augmented by acute ANG II stimulation in vitro. Hydrogen peroxide measured by dichlorofluorescein was not affected by ANG II. GA derived from postischemic animals manifested significantly greater constrictor responses in vitro to ANG II than GA from sham-operated controls. The addition of the superoxide scavenging reagent Tempol (10−5 M) normalized the response to values similar to sham-operated controls. Apocynin (10−6 M) and endothelial denudation nearly abrogated all ANG II-stimulated constrictor activity in GA from post-AKI rats, suggesting an important role for an endothelial-derived source of peripheral oxidative stress. Apocynin treatment in vivo abrogated GA oxidant stress and attenuated ANG II-induced pressor responses post-AKI. Interestingly, gene expression studies in GA vessels indicated a paradoxical reduction in NADPH oxidase subunit and AT1-receptor genes and no effect on several antioxidant genes. Taken together, this study demonstrates that AKI alters peripheral vascular responses by increasing oxidant stress, likely in the endothelium, via an undefined mechanism.
Genomics of cardiac remodeling in angiotensin II-treated wild-type and LOX-1-deficient mice
Authors: Kang Bum-Yong , Hu Changping , Ryu Sunhyo , Khan Junaid A. , Biancolella Michela , Prayaga Sastry , Seung Ki-Bae , Novelli Giuseppe , Mehta Paulette , Mehta Jawahar L.
Published: March 2010

We studied the gene expression profile during cardiac hypertrophy induced by angiotensin (ANG) II in wild-type mice and the influence of LOX-1 deletion on the gene expression profile. Wild-type and LOX-1 knockout mice were given saline or ANG II infusion for 4 wk. The saline-treated LOX-1 knockout mice showed upregulation of several genes including Ddx3y and Eif2s3y. ANG II infusion enhanced expression of genes known to be associated with cardiac remodeling, such as Agt, Ace, Timp4, Fstl, and Tnfrst12a, as well as oxidant stress-related genes Gnaq, Sos1, and Rac1. Some other strongly upregulated genes identified in this study have not been previously associated with LOX-1 deletion and/or hypertension. To confirm these observations with ANG II infusion and LOX-1 deletion, cultured HL-1 mouse cardiomyocytes were exposed to ANG II or transfected with pCI-neo/LOX-1, which resulted in severalfold increase in reactive oxygen species generation, upregulation of ANG II type 1 (AT1) receptor, and cardiomyocyte growth. Quantitative PCR analysis of these treated cardiomyocytes confirmed upregulation of many of the genes identified in the in vivo study. This study provides the first set of data on the gene expression profiling of cardiac tissue treated with ANG II and expands on the important role of LOX-1 in cardiac response to ANG II.