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Japan is a country with many disasters such as earthquakes and heavy rains. Disasters cannot be prevented, however, efforts to reduce secondary damage was performed by the nation. Sleeping without beds in a shelter has a high prevalence of economy class syndrome. Due to the living environment of shelter, cots were introduced to each local government. As a result, cots were able to prevent hypothermia and freezing death. Shelters in cold regions use powerful heating devices, which lowers humidity and increases the risk of fire. Cardboard beds were made from paper so that, the user was not completely convinced of the fire risk. In this study, we investigated the combustion behavior and effects of flame-retardants on cardboard by combustion test and thermal analysis. Phosphorus-Nitrogen flame-retardant was possible to suppress the combustion which emitted a large amount of carbon monoxide.

Freezing triggers extracellular ice formation leading to cell dehydration and deformation during a freeze–thaw cycle. Many plant species increase their freezing tolerance during exposure to low, non-freezing temperatures, a process termed cold acclimation. In addition, exposure to mild freezing temperatures after cold acclimation evokes a further increase in freezing tolerance (sub-zero acclimation). Previous transcriptome and proteome analyses indicate that cell wall remodelling may be particularly important for sub-zero acclimation. In the present study, we used a combination of immunohistochemical, chemical and spectroscopic analyses to characterize the cell walls of Arabidopsis thaliana and characterized a mutant in the XTH19 gene, encoding a xyloglucan endotransglucosylase/hydrolase (XTH). The mutant showed reduced freezing tolerance after both cold and sub-zero acclimation, compared to the Col-0 wild type, which was associated with differences in cell wall composition and structure. Most strikingly, immunohistochemistry in combination with 3D reconstruction of centres of rosette indicated that epitopes of the xyloglucan-specific antibody LM25 were highly abundant in the vasculature of Col-0 plants after sub-zero acclimation but absent in the XTH19 mutant. Taken together, our data shed new light on the potential roles of cell wall remodelling for the increased freezing tolerance observed after low temperature acclimation.

A TCAD model to simulate program/erase characteristics of 3D charge trap flash memory cells is constructed and calibrated with the experiment. The mechanism of the program characteristics degradation of the semicircular cells are studied using the TCAD model and it is clarified that the current leakage path due to the fringe parasitic transistor causes the degradation. An initial charge injection technique is proposed to suppress the parasitic leakage current to improve the program characteristics of the semicircular cells.

Background:It has long been recognized that immune-mediated inflammatory diseases, such as rheumatoid arthritis (RA), are prone to coexist with depression due to the effects of cytokines, and that these two illnesses lead to an elevation in patients’ pain. However, we often encounter patients with RA who suffer from residual pain despite an improvement in disease activity and inflammation. The specific psychological factors associated with residual pain have not yet been clarified. In addition to the traditional psychological factors, such as depression and anxiety, we focused on pain catastrophizing due to the distortion of pain perception and explored its association with residual pain.Objectives:To examine whether psychological factors, such as pain catastrophizing, depression, and anxiety, are associated with self-reported pain visual analogue scale (pain-VAS) scores in RA patients with 1 or less on 28joints- swollen/tender counts (SJC/TJC) and CRP.Methods:This was a cross-sectional study of 290 RA outpatients (85% of whom were women) with scores of less than 1 on SJC, TJC, and CRP, with a median (IQR) age of 66 (57–73) years. The participants completed questionnaires, including pain VAS (0–100 mm), Pain Catastrophizing Scale (PCS, 0–52 scale), and Hospital Depression and Anxiety Scale (HADS, 0–42 scale). Using linear regression analyses, we analysed whether PC (PCS ≥30), depression (HADS-D ≥11), and anxiety (HADS-A ≥11) (independent variables) were associated with pain VAS scores (dependent variable). After univariate regression analysis, multivariate analysis adjusted for confounding factors was performed.Results:Patients reported a wide range of pain severity with a median (range) pain VAS score of 9 (0–96mm). The prevalence of anxiety and depression were 5.5% and 5.9%, respectively. Meanwhile, 24.1% of the patients experienced pain catastrophizing. Pain catastrophizing was associated with pain VAS scores in univariate and multivariate analyses (Table 1). The presence of anxiety and depression was not associated with pain VAS scores in any model. Multivariate analysis of other covariates showed that age, disease duration, and presence of SJC/TJC of joints other than the 28 joints were positively correlated with pain VAS scores.Table 1.Univariate and multivariate regression analysis for independent variables associated with pain-VAS scoresUnivariateMultivariate independent variablesModel 1*Model 2**Pain catastrophizingEstimate3.74.13.695%CI 0.7 to 6.61.1 to 7.00.5 to 6.6p-value0.0150.0060.021AnxietyEstimate3.74.40.595%CI -1.9 to 9.2 -1.0 to 9.9 -3.5 to 7.9p value0.1980.1080.453DepressionEstimate3.54.23.995%CI -1.9 to 8.9 -1.1 to 9.5 -1.9 to 8.7p-value0.2040.1190.210The covariates in multivariate analysis are as follows: age, sex, body mass index, disease duration, Steinbrocker’s Stage, prednisolone dosage, biologic agents use, and presence of swollen joint counts/tender joint counts of joints other than the 28 joints.*Model 1: each psychological independent variable and the above covariates.**Model 2: all psychological independent variables and the above covariates.Conclusion:Pain catastrophizing was associated with pain VAS scores in RA patients with 1 or less on 28joints-SJC/TJC and CRP, emphasising that residual pain in the patients should be treated in a biopsychosocial framework focussing on pain catastrophizing.Disclosure of Interests:Tamami Yoshida: None declared, Motomu Hashimoto Speakers bureau: Mitsubishi Tanabe Pharma Corporation; Bristol-Myers Squibb; Eisai Co., Ltd.; and Eli Lilly and Company., Grant/research support from: Mitsubishi Tanabe Pharma Corporation; Bristol-Myers Squibb; Eisai Co., Ltd.; and Eli Lilly and Company., Kosaku Murakami Speakers bureau: Eisai Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Pfizer Inc.; Bristol-Myers Squibb; Mitsubishi Tanabe Pharma Co; UCB Japan Co., Ltd.; Daiichi Sankyo Co., Ltd.; and Astellas Pharma Inc., Consultant of: Eisai Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Pfizer Inc.; Bristol-Myers Squibb; Mitsubishi Tanabe Pharma Co; UCB Japan Co., Ltd.; Daiichi Sankyo Co., Ltd.; and Astellas Pharma Inc., Koichi Murata Speakers bureau: Eisai Co., Ltd. and Astellas Pharma Inc., Consultant of: Eisai Co., Ltd. and Astellas Pharma Inc., Kohei Nishitani Grant/research support from: Asahi-Kasei Pharma., Ryu Watanabe Speakers bureau: Mitsubishi Tanabe Pharma Co; Pfizer Inc.; Sanofi S.A.; AbbVie GK; Asahi Kasei Pharma; Eisai Co., Ltd.; Eli Lilly and Company; Bristol-Myers Squibb; and Janssen Pharmaceutical K.K., Teruhide Koyama: None declared, Ritei Uehara: None declared, Masao Tanaka Speakers bureau: AbbVie GK, Asahi Kasei Pharma., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Co., Novartis Pharma K.K., Pfizer Inc., Taisyo Pharma., Ltd., UCB Japan Co., Ltd., Grant/research support from: AbbVie GK, Asahi Kasei Pharma., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Co., Novartis Pharma K.K., Pfizer Inc., Taisyo Pharma., Ltd., UCB Japan Co., Ltd., Hiromu Ito Grant/research support from: Bristol-Myers Squibb, Eisai Co, Taisyo Pharma., and Mochida., Shuichi Matsuda: None declared

We present the progress on the upgrade status of the J-KAREN-P , which is a Ti: Sapphire laser aiming at the intensity of 1022 W/cm2 at the repetition rate of 0.1 Hz. The upgrade includes two pilot experiments in order to show the laser performance on target. The first experiment is to generate high-energy ions from thin-foil target. The second experiment is the high-order harmonic at a relativistic intensity. Currently, laser acceleration of protons is being tested and we have obtained 32 MeV protons from a 5-µm stainless steel target irradiated by a 14-J, 30-fs laser pulse. In addition, a joint program toward compact X-ray free-electron laser based on laser electron acceleration is presented briefly and the corresponding J-KAREN-P work is presented.

A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The proton beam profiler uses differential filtering to provide coarse energy resolution and a flexible design to allow optimisation for expected beam energy range and trade-off between spatial and energy resolution depending on the application. A plastic scintillator detector, imaged with a standard 12-bit scientific camera, allows data to be taken at a high repetition rate. An algorithm encompassing the scintillator non-linearity is described to estimate the proton spectrum at different spatial locations.

Experimental studies on the formation of highly charged ions of medium-Z elements using femtosecond laser pulses with different contrast levels were carried out. Multiply charged Fe ions were generated by laser pulses with 35 fs duration and an intensity exceeding 1021 W/cm2. Using high-resolution X-ray spectroscopic methods, bulk electron temperature of the generated plasma has been identified. It is shown that the presence of a laser pre-pulse at a contrast level of 105–106 with respect to the main pulse drastically decreases the degree of Fe ionization. We conclude that an effective source of energetic, multiply charged moderate and high-Z ions based on femtosecond laser–plasma interactions can be created only using laser pulses of ultra-high contrast.

We report on the J-KAREN-P laser facility at QST, which can provide PW peak power at 0.1 Hz on target. The system can deliver short pulses with an energy of 30 J and pulse duration of 30 fs after compression with a contrast level of better than 1012. Such performance in high field science will give rise to the birth of new applications and breakthroughs, which include relativistic particle acceleration, bright x-ray source generation, and nuclear activation. The current achieved laser intensity on target is up to > 9x1021 Wcm-2 with an energy of ~9 J on target. The interaction with a 3 to 5- μm stainless steel tape target provides us electrons with a typical temperature of more than 10 MeV and energetic proton beams with typical maximum energies of > 40 MeV with good reproducibility. The protons are accelerated in the Target Normal Sheath Acceleration regime, which is suitable for many applications including as an injector into a beamline for medical use, which is one of our objectives.

Broadband-pulses are amplified to 63 J and compressed to 30 fs. A peak intensity of 1022 W/cm2 by focusing a 0.3 PW laser beam with an f/1.4 off-axis parabolic mirror is achievable on target.

This study is intended to assess low frequency sound radiated from a viaduct under normal traffic. The bridge comprises steel box girders and wide cantilever decks on which vehicles pass. The low frequency sound and the acceleration response of the bridge under normal traffic are measured to investigate how bridge vibrations affect the low frequency sound observed near the bridge. Observations demonstrate that strong relationships exist between frequency characteristic of bridge`s acceleration response and the sound pressure level of low frequency sound. A noteworthy point is that the dynamic feature of the sound pressure level is mostly affected by dynamic feature of the span locating near the observation point.

We report about nonlinear growth of x-ray emission intensity emitted from plasma generated by femtosecond petawatt laser pulses irradiating stainless steel foils. X-ray emission intensity increases as ~ I 4.5 with laser intensity I on a target. High spectrally resolved x-ray emission from front and rear surfaces of 5 μm thickness stainless steel targets were obtained at the wavelength range 1.7–2.1 A, for the first time in experiments at femtosecond petawatt laser facility J-KAREN-P. Total intensity of front x-ray spectra three times dominates to rear side spectra for maximum laser intensity I ≈ 3.2×1021 W/cm2. Growth of x-ray emission is mostly determined by contribution of bremsstrahlung radiation that allowed estimating bulk electron plasma temperature for various magnitude of laser intensity on target.

We report on the spectra of x-rays emitted from dense plasma generated via irradiation of thin stainless steel foils by ultra-relativistic femtosecond laser pulses (intensities ~3 × 10^21 W/cm^2). Kinetic modelling was used to estimate electron plasma density and temperature, demonstrating Te ~2.1 keV for Ne ~5 × 10^22 cm^−3 in the hottest emission region. Thus, it is experimentally demonstrated for the first time that the laser pulse of over 10^21 W/cm^2 intensity is absorbed neither in the solid density plasma nor in a pre-plasma of a common critical density, but in the matter of so called relativistic critical density.

We have studied EuPtP, which undergoes two successive valence transitions at ${T}_{\mathrm{A}}\ensuremath{\sim}240$ K and ${T}_{\mathrm{B}}\ensuremath{\sim}200$ K by $^{31}\mathrm{P}$-nuclear magnetic resonance (NMR) measurements. From the analysis of NMR spectra, we obtained plausible ordered structures and Eu valence states in three phases divided by ${T}_{\mathrm{A}}$ and ${T}_{\mathrm{B}}$. These ordered structures well explain observed inequivalent P sites and the intensity ratio of the NMR spectra arising from these P sites. The results are also in good accordance with mean Eu valence measured by the x-ray absorption spectroscopy. We also discuss Eu $4f$ states and the origin of the transitions from the measurements of nuclear spin lattice relaxation rate and hyperfine coupling constant.

A 2.2-V operation, single-chip GaAs MMIC transceiver has been successfully developed for 2.4-GHz-band wireless applications such as wireless local area network terminals. The chip is fabricated using a planar self-aligned gate field-effect transistor. To generate sufficient negative voltage for gate-biasing and to enhance switch power handling capability under a 2.2-V supply, a newly designed negative voltage generator with a voltage doubler (NVG-VD) and a switch control logic circuit are integrated on the chip, together with a power amplifier, a transmit/receive switch, and a low-noise amplifier. The NVG-VD is designed to produce both a 3.3-V positive step-up voltage and a -2.1-V negative voltage under 2.2 V in operation voltage. Biased with these outputs, the logic circuit accommodates high power outputs of over 25 dBm with a low operating voltage of 2.2 V in transmit mode, With a 2.45-GHz modulated signal based on IS-95 standards, a 21-dBm output power and a 33% efficiency are obtained at a /spl plusmn/1.25-MHz-offset adjacent channel power rejection of -45 dBc. In receive mode, a low-noise amplifier achieves a 1.8-dB noise figure and an 11-dB gain with a 3.0-mA current. This transceiver enables significant size and weight reductions in 2.4-GHz-band wireless application terminals.

By using the Magnetic Resonance Imaging (MRI) technique, we studied the spatial recovery of the longitudinal magnetization of liquid 3 He- 4 He mixtures in a 2mm × 2mm × 20mm rectangular parallelepiped sample cell below 1 K. We applied saturation pulses to destroy the magnetization and took two-dimensional pictures of the recovery of the magnetization in three orthogonal planes by the MRI as a function of waiting times. We found from the MRI pictures that the bulk relaxation process was so slow that the surface relaxation and the subsequent diffusion process were dominant mechanisms for the 3He spin relaxation. When the mixture was phase-separated, the magnetization in the concentrated side recovered much faster than that in the diluted side. It was also shown that there was no extra magnetization recovery at the phase boundary. As a result, the magnetization diffused from the concentrated side, flowed through the phase boundary into the diluted side and caused a magnetization recovery in the diluted side.

We have developed a Magnetic Resonance Imaging (MRI) technique applicable for ultra low temperature physics. In contrast to conventional MRI for general use where a pulsed-field gradient method is commonly used, we used a steady-field gradient method to avoid an eddy current heating due to metallic parts around the sample cell. We applied the MRI for 3 He-4 He mixture liquid with a critical concentration below 1 K and visualized the shape of the phase-separated boundary. We obtained two-dimensional space resolution of a few 10 μm. We extracted the interfacial tension of the boundary which was in good agreement with reported values. The contact angle of the boundary to the cell wall was small at low temperature and increased toward 90° near the critical temperature.

The authors present formation conditions for ion-implanted regions of a GaAs buried p-layer lightly doped drain (BPLDD) MESFET that can improve short-channel effect, V/sub th/ uniformity, and FET operating speed, simultaneously. For 0.7- mu m gates, a Mg/sup +/ dose of 2*10/sup 12/ cm/sup -2/ at 300 keV and a Si/sup +/ dose of 2*10/sup 12/ cm/sup -2/ at 50 keV are suitable for the p layer and n' layer, respectively. A sigma V/sub th/ of 7 mV is realized. Gate-edge capacitance of the 0.7- mu m-gate BPLDD that consists of both overlap capacitance and fringing capacitance is successfully reduced to 0.5 fF/ mu m, which is about 50% of that of a non-LDD buried p-layer (BP) FET. Another parasitic capacitance due to the p-layer was found to have less effect on the speed than the gate-edge one. Consequently, the gate propagation delay time of the BPLDD can be reduced to 15 ps at power dissipation of 1 mW/gate, which is about 65% of that of a BP. Applying the 0.7- mu m-gate BPLDD to 16-kb SRAMs, the authors have obtained a maximum access time of less than 5 ns with a galloping test pattern. >

The authors have realized 16-kb SRAMs with maximum address access time of less than 5 ns and typical power dissipation of less than 2 W at temperatures ranging from 25 degrees C to 100 degrees C. For the RAMs, they have developed a triple-level Au-based interconnection technology that reduces the wiring length and chip size of the SRAM so as to achieve high speed and high yield. Consequently, the wiring length and chip size are reduced to 69% and 58%, respectively, of those obtained by in previous work. The authors experimentally compared the delay time incurred by double-level interconnection and that by triple-level interconnection. This ratio is found to agree well with the simulated one by a model with distributed RC delay. After successfully suppressing Au hillock generation by lowering the process temperature, yield per wafer of 10% is obtained. >

Genetic differences which exist in the prion protein gene (PRNP) have been reported to influence susceptibility of humans, sheep and goats to prion diseases. In cattle, however, none of the known coding polymorphisms has a direct effect on bovine spongiform encephalopathy (BSE). It has been reported that 23-bp insertion/deletion (indel) polymorphisms within the promoter region have a tentative association to BSE susceptibility in German cattle, and a lower number of 24-bp repeat units in the open reading frame (ORF) was reported to reduce BSE susceptibility in transgenic mice. In this study, because of the hypothesis that bovine PRNP promoter polymorphisms cause changes in PRNP expression, we genotyped PRNP polymorphisms in the promoter and intron 1 using 218 genomic DNA samples from two Japanese cattle breeds. We also analysed the expression levels of prion in 40 animals by quantification of real-time PCR using mRNAs extracted from the medulla oblongata to study the relationship between PRNP genotypes and PRNP expression. We found a significant correlation between promoter indel polymorphisms and PRNP-mRNA expression (P(0.0413)) and therefore hypothesize that differences in polymorphisms could be one of the causes of differences in PRNP expression levels. We also report a novel difference in PRNP expression (P < 0.0001) between Japanese Black and Japanese Brown cattle breeds. There was no significant difference based on age and sex of the animals.

A GaAs MESFET with a partially depleted p layer that has a specific application to SRAMs has been developed. The short-channel effect is well suppressed for gate lengths down to 0.5 mu m by a rather dense p layer buried under the channel. Its acceptor ion dose is as high as 2*10/sup 12/ cm/sup -2/, which corresponds to a partially depleted condition. As for applications for SRAMs, it is possible to attain fully functional 7-ns 4-kb SRAMs that are operative at 75 degrees C by using the FET with a 1- mu m gate. A chip yield of 22% has been achieved in a 3-in wafer. >

A GaAs 4 K*4-b static-Ram (SRAM) with high speed and high reliability has been developed for practical systems. By adopting a novel basic circuit technique to the peripheral circuits, the RAM operates over a wide temperature range. By using a novel memory cell, the soft-error rate is reduced to less than that of commercial silicon emitter-coupled-logic (ECL) RAMs. Furthermore, by adopting a triple-level interconnection process, the chip area is reduced to 58% of that using a double-level one. The RAM operates at a single supply voltage of 1.8 V. At an ambient temperature of between 25 and 100 degrees C, the RAM is guaranteed a 5.0-ns access time, 2.0-W power dissipation, and +or-0.1-V supply voltage tolerance. >

A GaAs 1 K*4-kb SRAM designed using a novel circuit technology is described. To reduce the temperature dependence and the scattering of the access time, it was necessary to increase the signal voltage swing and to reduce the leakage current in access transistors of unselected memory cells. In the 4-kb SRAM, source-follower circuits were adopted to increase the voltage swing, and the storage nodes of unselected memory cells were raised by about 0.6 V to reduce the subthreshold leakage current in the access transistors. The 4-kb SRAM was fabricated using 1.0- mu m self-aligned MESFETs with buried p-layers beneath the FET regions. A maximum address access time of 7 ns and a power dissipation of 850 mW were obtained for the galloping test pattern at 75 degrees C. Little change in the address access time was observed between 0 and 75 degrees C. >

A novel image synthesis method of an object at arbitrary viewpoint by using the 3-D geometric model and several camera images is proposed. Although the image-based rendering synthesizes the relatively accurate diffuse reflection component from the camera images from different viewpoints, it can not synthesize the specular reflection component with sufficient accuracy as the movement of the specular reflection component as the changes in viewpoints are not taken into consideration. In order to overcome this problem, we propose a method for synthesizing the arbitrary viewpoint images with the use of the displacement vectors of the specular reflection components. The displacement vectors are estimated by a hexagonal matching algorithm based on the triangle mesh model which was modified for arbitrary shaped images. In the hexagonal matching, the images synthesized from 3-D geometric model of a real object and camera images are used as reference image. The experiments show that the proposed method reconstructs the specular reflection components more accurately and also improves the coding performance compared to the conventional methods.

A GaAs SRAM utilizing a self aligned FET and double-level metal technology will be disclosed. Address predecoders and controlled gain stage loading give an access time of 15ns. A 5.8×4.7mm chip dissipates' 1W with a power supply of 1V.

A GaAs 4 K*4 b SRAM (static RAM) with improved alpha particle immunity is presented. By using a novel circuit technology and a buried p-layer FET, the critical charge of the memory cell has been increased and the collected charge decreased. The soft error rate of a 16-kb SRAM is reduced by about four orders of magnitude compared to that of a GaAs 4-kb SRAM consisting of conventional memory cells; it is also less than that of the commercially available silicon 1-kb ECL RAM. An address access time of 7.0 ns with 2.1-W power dissipation has been obtained at 75 degrees C. The RAM operates at the single supply voltage of 1.8 V. >

The dry etching technique is investigated to achieve high-aspect-ratio via holes with smooth inner surface for the application of high-power GaAs MESFET with the source island via hole (SIV) structure. Mask materials and etching conditions are optimized to obtain a high aspect ratio of 2.6. The uniformity of the etched depth is +or-3.5% deviation across a 3-in wafer, and the reproducibility is +or-5.5% deviation. This technique allows the SIV FET with dry etched via holes to realize a packing density 1.7 times higher than that of conventional FETs. At 18 GHz, the SIV FET with 1350- mu m gate width provides a power output of 26.2 dBm at 1-dB gain compression and a linear power gain of 7.5 dB. >

The authors describe a GaAs 1 K*4 static random-access memory (SRAM) which has been designed using a novel circuit technology to reduce the scattering and the temperature dependence of the access time. To reduce the subthreshold leakage current in the access transistors of the unselected memory cells, the baselines connected to the unselected memory cells were raised from the ground level. The 4-Kb SRAM was fabricated using 1.0- mu m self-aligned MESFETs with buried p-layers beneath the FET regions. A maximum address access time of 7 ns and a power dissipation of 850 mW were obtained for the galloping test pattern at 75 degrees C. Little change in the address access time was observed over 0 to 75 degrees C. >

A tracking servo LSI for an 8-mm VCR has been developed by utilizing 3- mu m high-speed bipolar CMOS technology. The chip contains analog functions, such as a low-noise amplifier, a gain-control amplifier, balanced demodulators, rectifiers, a precision Schmit amplifier and subtracter; mixed analog-digital functions, such as switched-capacitor filters, sample-and-hold amplifiers and analog switches; and digital functions, such as an oscillator, a clock generator, counters, and an externally selectable four-mode counter. High-performance mixed analog/digital performance is obtained by combined bipolar and CMOS devices. By integrating all necessary functions on one chip, no adjustment of the servo system is needed and low power capability has been realized. >

A self-aligned gate MESFET with a partially depleted p-layer buried underneath the channel layer is proposed for achieving an excellent threshold voltage (V/sub th/) uniformity. By increasing the implantation dose for the p-layer as high as 2*10/sup 12/ cm, the short-channel effect can be successfully suppressed for gate length as short as 0.5 mu m, and high uniformity of V/sub th/ can be obtained. A threshold voltage variation as low as 9 mV for V/sub th/ of -400 mV was obtained, together with g/sub m/ (590 mS/mm) and K-value (490 mS./Vmm). This self-aligned gate MESFET was used to fabricate a 4-Kb SRAM (static random-access memory), and fully functional chips were obtained with an excellent yield as high as 22% in a wafer. >

A BPLDD SAGFET (self-aligned gate MESFET) with reduced source-to-gate spacing has been developed for high-speed GaAs LSIs. The short channel effect is drastically suppressed by reducing source-to-gate spacing to 0.2 mu m. Even for 0.2- mu m gate, the standard deviation of V/sub th/ is as small as 34 mV over a 3-in wafer. Transconductance as high as 480 mS/mm is achieved. f/sub T/ is estimated to be 85 GHz. High-performance and highly uniform subquarter-micron BPLDD SAGFETs with reduced source-to-gate spacing are very promising for ultrahigh-speed LSIs. >

A novel multifeed gate configuration using air-bridge metallization is demonstrated for low-noise high electron mobility transistors (HEMTs). The configuration is designed according to the detailed analysis of parasitic gate capacitances. Very low noise figures of 0.55 and 1.6 dB have been achieved at 12 and 40 GHz for 0.25 mu m gate AlGaAs/InGaAs pseudomorphic HEMT respectively. A noise figure of 4.1 dB and a gain of 12.2 dB at 40 GHz were obtained for two-stage HEMT monolithic microwave integrated circuits. >

It is reported that focused ion beam (FIB) techniques have been successfully applied to optimization of an X-band single stage MMIC (monolithic microwave integrated circuit) amplifier. Modification of MMIC components has been performed by etching of circuit patterns and depositing tungsten films. RF performance of the MMIC has been adjusted to the designed one without any further wafer process. It shows that these techniques are promising to develop MMICs. >

A novel FET structure with buried plate heat sink is proposed which gives higher power output and power added efficiency with easy wafer and chip handling. The substrate thickness is extremely thin (30 mu m) with a 70- mu m-thick gold-plated heat sink for the FET region, and it is 100- mu m for the remaining part of the chip. The buried plated heat sink FET with a gate width of 350 mu m provides a superior low thermal resistance of 16 degrees C/W, a power output as high as 27.9 dBm with an excellent power added efficiency of 32% at 1-dB compression point, and a linear power gain of 8.3 dB at 18 GHz. The fabrication technique, the structural reliability, the thermal resistance, and the RF performances of the newly developed FETs are presented. >

A fully functional GaAs 16 K SRAM is realized with an address access time of 4.4 ns and a power dissipation of 2 W. In the fabrication process, a triple-level Au-based interconnection technology is developed to reduce the wiring length, which strongly affects the delay time. The wiring length and chip size are drastically reduced to 69% and 58% of those previously reported by the authors, respectively. High wafer yield of 10% is also obtained by using this technology. Moreover, high-speed and stable operation of less than 5 ns is achieved for the temperature range from 25 to 100 degrees C. >

Design and experimental results of a 2-V operation single-chip GaAs T/R-MMIC front-end are described for 1.9-GHz personal communication terminals. This chip, fabricated with planar self-aligned gate FET process useful for low-cost and high-volume production, integrates RF front-end analog circuits-a power amplifier, a T/R-switch, and a low-noise amplifier. Additionally integrated are a newly designed voltage doubler-negative voltage generator (VDNVG) and a control logic circuit to control transmit and receive functions. The chip is capable of delivering 21-dBm output power at 39 % efficiency with 2-V single power supply in transmit mode. By utilizing up-voltage and negative voltages generated from the generator, the new interface circuit enables the switch to handle high power outputs over 24 dBm with 0.55-dB insertion loss.