Showing papers presented at "International Meeting for Future of Electron Devices, Kansai in 2013"
Rohm1
TL;DR: In this article, a new SiC MOSFET structure with both gate and source trenches is presented, which greatly reduces device on-resistance while preventing oxide destruction at the gate trench bottoms.
Abstract: SiC Power devices are expected to greatly improve the efficiencies and operating capabilities of next generation electric and hybrid electric vehicles. The use of these devices allows for drastic size and weight reduction at the module and system levels of motor drives used in automotive applications. A new SiC MOSFET structure with both gate and source trenches is presented. This greatly reduces device on-resistance while preventing oxide destruction at the gate trench bottoms. Finally new packaging methods under development are outlined that take advantage of the benefits these new devices have to offer by transfer molding them in a high temperature resistant epoxy resin. This leads to modules with low thermal resistance and high power density that, when configured as a three phase inverter, reduce total system footprint and parasitic inductance.
16 citations
05 Jun 2013
TL;DR: In this article, a 79 GHz power amplifier using 4-stages common-source structure is presented, and the lifetime results of PA at two different biases in 40nm CMOS process are shown.
Abstract: A 79 GHz power amplifier (PA) using 4-stages common-source structure is presented in this paper. To evaluate temperature dependence of circuit characteristics, the PA is measured at various temperatures. At room temperature (RT) and 100°C, the saturated output power is 7.6 and 7.1dBm, the maximum PAE is 6.2% and 4.9%, respectively. The reliability and lifetime of PA is also obtained. To the author's knowledge, this is the first paper to show the lifetime results of PA at two different biases in 40nm CMOS process.
9 citations
05 Jun 2013
TL;DR: The purpose of this study was to fabricate a mixer based on the Gilbert cell mixer using the 0.18 μm 1P6M standard CMOS process for long-term evolution small-cell base stations and high linearity was essential.
Abstract: The purpose of this study was to fabricate a mixer based on the Gilbert cell mixer using the 0.18 μm 1P6M standard CMOS process. The primary target of this mixer was long-term evolution (LTE) small-cell base stations; thus, high linearity was essential. This up-conversion mixer can convert a 100-MHz intermediate frequency into a higher 1.8-GHz radio frequency for wireless applications. A high-linearity mixer was achieved by employing the derivative superposition (DS) method and a source degeneration resistor, while using a folded mixer to achieve low voltages. The post-layout simulation result was a conversion gain of 5 dB, an input third-order intercept point (IIP3) of 14.6 dBm, supply voltage of 1.2 V, and a power consumption of 9.54 mW.
7 citations
05 Jun 2013
TL;DR: The neuron consisting of eight TFTs and synapse of only one TFT is realized, leading to a super-large, self-learning, and high-flexibility system.
Abstract: We are developing neural networks of device level using thin-film transistors (TFT). By adopting an interconnect-type neural network and utilizing a characteristic shift of poly-Si TFTs as a variable strength of synapse connection, which was originally an issue, we realized the neuron consisting of eight TFTs and synapse of only one TFT. Particularly in this presentation, we confirmed the working by a circuit where the input and output elements are asymmetric. This is a result leading to a super-large, self-learning, and high-flexibility system.
4 citations
05 Jun 2013
TL;DR: In this article, the optical transmittance of ZnO films were measured by a spectrophotometer in the visible range (400-800nm) and the crystal structure was characterized by X-ray diffraction.
Abstract: ZnO films were prepared on glass substrates by two different methods. One is a spin-coating method followed by annealing in oxygen gas. The other is an evaporation of zinc metal followed by oxidation. The crystal structure was characterized by X-ray diffraction. The optical transmittance was recorded by a spectrophotometer in the visible range (400-800nm). It was found that the normalized optical transmittances of the ZnO films prepared using vacuum evaporation method were over 90% which were much larger than those of the films using spin-coating method.
3 citations
05 Jun 2013
TL;DR: It is demonstrated that 20-nm XCT-SOI CMOS devices can support low-energy circuit applications and three-dimensional device simulations consider the viability ofXCT-CMOS devices in the sub-30-nm-regime.
Abstract: This paper uses three-dimensional device simulations to consider the viability of XCT-CMOS devices in the sub-30-nm-regime. It is demonstrated that 20-nm XCT-SOI CMOS devices can support low-energy circuit applications.
3 citations
05 Jun 2013
TL;DR: In this paper, the authors presented the measurements of power noise (Vdd noise) waveforms of a 5-stage inverter chain, using on-chip noise monitor circuits (OCM).
Abstract: This paper presents the measurements of power noise (Vdd noise) waveforms of a 5-stage inverter chain, using on-chip noise monitor circuits (OCM). The fine resolution of 0.4 mV in voltage and 12.5 ps in timing are realized. The undesired voltage variation by signal buffers in I/O cells is carefully eliminated by three means; (i) isolation of power domains, (ii) subtraction of background noise waveforms, and (iii) averaging iteratively captured waveforms.
3 citations
05 Jun 2013
TL;DR: In this paper, the DC characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on a free-standing GaN substrate were described.
Abstract: This paper describes DC characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on a free-standing GaN substrate. The three terminal breakdown voltage of the fabricated HEMT with a gate length of 3 μm exhibited a linear increase with increasing the gate-to-drain distance (Lgd), reaching more than 1200 V at Lgd=25 μm. It was found that the ON/OFF ratio in the drain current was only 104, indicating the need for further improvements in buffer structure design.
3 citations
05 Jun 2013
TL;DR: In this paper, a lowvoltage operation method to yield surface airflow with electrohydrodynamic (EHD) force is proposed, and the experimental results show that the airflow is induced by EHD force based on discharged particle, asymmetric distribution of wall charge, and strong electric field in the vicinity of the device surface.
Abstract: A novel low-voltage-operation method to yield surface airflow with electrohydrodynamic (EHD) force is proposed. The experimental results show (1) airflow near the device surface, (2) purple glow by surface discharge, and (3) instant transfer of electric charge among three linear electrodes where the supplied voltages generate strong electric field. The velocity of airflow is 2.0m/s at maximum. The observed charge transfer among the electrodes can be explained to correspond to formation of “wall charge” above the device surface. This fact indicates that the airflow is induced by EHD force based on discharged particle, asymmetric distribution of wall charge, and strong electric field in the vicinity of the device surface.
2 citations
05 Jun 2013
TL;DR: In this article, the power efficiency in a WPT system is measured under the condition of various transmission distances and the optimum control of the parameters is considered in the system from the results.
Abstract: In this study, the power efficiency in a WPT system is measured under the condition of various transmission distances and the optimum control of the parameters is considered in the system from the results. The change of the resonance frequencies according to the change of coupling coefficients improve the power transmission efficiencies of the system compared to the case of the fixed resonance frequency. In addition, we reveal the trade-off between the magnitude of the output power and the power efficiency in terms of the resonance frequency. From our analysis, the trade-off resonance frequency is derived at various transmission distances by numerical simulation.
2 citations
05 Jun 2013
TL;DR: In this paper, the authors developed a CMOS image sensor dedicated to digital enzyme-linked immunosorbent assay (ELISA) which is sensitive to small changes of fluorescent intensity.
Abstract: Digital enzyme-linked immunosorbent assay (ELISA) systems can be miniaturized by applying on-chip CMOS image sensor detection instead of conventional fluorescence microscopy. We have developed a CMOS image sensor dedicated to digital ELISA, which is sensitive to small changes of fluorescent intensity.
05 Jun 2013
TL;DR: In this paper, a detailed investigation of the impact of using a pocket in a Schottky-barrier tunneling FET (SBTFET) is reported, and it is found that a pocket at both the source and the drain ends results in overall improvement of the device performance.
Abstract: In this paper, a detailed investigation of the impact of using a pocket in a Schottky-barrier tunneling FET (SBTFET) is reported. It is found that a pocket at both the source and the drain ends results in overall improvement of the device performance.
05 Jun 2013
TL;DR: In this paper, a proposed NMOS-centered 6T SRAM cell layout that reduces a neutron-induced multiple-cell-upset (MCU) SER on the same wordline is presented.
Abstract: This paper presents a proposed NMOS-centered 6T SRAM cell layout that reduces a neutron-induced multiple-cell-upset (MCU) SER on a same wordline. We implemented an 1-Mb SRAM macro in a 65-nm CMOS process and irradiated neutrons as a neutron-accelerated test to evaluate the MCU SER. The proposed 6T SRAM macro improves the horizontal MCU SER by 67-98% compared with a general macro that has PMOS-centered 6T SRAM cells.
05 Jun 2013
TL;DR: In this article, the authors measured the noise floor of spectrum and phase noise of the proposed differential dual-modulus 10/11 prescaler based on ILFD for various supply voltages and found that spurious noises arise and the phase noise degrades as the supply voltage reduces.
Abstract: We have measured the noise floor of spectrum and phase noise of the proposed differential dual-modulus 10/11 prescaler based on ILFD for various supply voltages and found that spurious noises arise and the phase noise degrades as the supply voltage reduces. The differential dual-modulus prescaler is implemented in 130 nm CMOS process and the core size is 40 × 20 μm2.
05 Jun 2013
TL;DR: In this paper, the authors numerically investigate the thermoelectric properties of Si nanostructures using Monte Carlo method coupled with one-dimensional Poisson equation and demonstrate that the barrier structure give rise to more pronounced electromotive force.
Abstract: We numerically investigate the thermoelectric properties of Si nanostructures using Monte Carlo method coupled with one-dimensional Poisson equation. It is demonstrated that the barrier structure give rise to more pronounced electromotive force. This is probably because the barriers only allowing high energy electrons to pass through, which results in so-called energy filtering effect.
05 Jun 2013
TL;DR: In this article, the interplay between photonic crystal and photoluminescence in a one-dimensional polysilicon was investigated, and it was shown that photoluminance is observed only when PL wavelength falls in the photonic band gap.
Abstract: We report on interplay between photonic crystal and photoluminescence in a one-dimensional photonic crystal. The one-dimensional photonic crystal reflects light within a certain range of wavelength. This range of wavelength is called photonic band gap. We measured reflectivity by changing incident angle of probe light, so as to shift the region of large reflectivity. We found that photoluminescence is observed only when PL wavelength falls in the photonic band gap. This result indicates that PL is intensified due to photonic crystal.
05 Jun 2013
TL;DR: In this article, the authors evaluate the impact of eddy current and anomalous skin effect on the loss of on-chip transmission-line in terahertz region above 100 GHz.
Abstract: This paper discusses loss of on-chip transmission-line in terahertz region. Above 100 GHz, modeling of on-chip transmission-line is an important issue. We evaluate the impact of eddy current and anomalous skin effect by a field solver. Simulation results show that eddy current in dummy fills has higher impact of 10% on transmission-line loss. Anomalous skin effect is not negligible, but its impact is about 5% at 100 GHz.
05 Jun 2013
TL;DR: In this paper, thin-film transistors fabricated using facing targets sputtering and a heat treatment at 400°C showed a very high transconductance as high as 91 mS/mm.
Abstract: IZO thin-film transistors fabricated using facing targets sputtering and a heat treatment at 400°C showed a very high transconductance as high as 91 mS/mm.
05 Jun 2013
TL;DR: In this paper, two dimensional electronic states in 4H-SiC inversion layers based on empirical pseudopotential approach, and the nonparabolicity effects on the quantum confinement are discussed.
Abstract: We calculate two dimensional electronic states in 4H-SiC inversion layers based on empirical pseudopotential approach, and the nonparabolicity effects on the quantum confinement are discussed. It is shown that the in-plane effective mass for electrons significantly increases under the strong confinement conditions in the case of (0001) oriented substrate, eventually causing the degradation of the inversion layer mobility.
05 Jun 2013
TL;DR: In this paper, a CO2 laser was irradiated to per-hydro-polysilazane by using spin-coated SiO2 precursor on a polycrystalline silicon substrate.
Abstract: CO2 laser was irradiated to per-hydro-polysilazane by us. Per-hydro-polysilazane as SiO2 precursor was spin-coated on the polycrystalline silicon substrate. CO2 laser was irradiated after prebaking Per-hydro-polysilazane film. Atomic force microscope analysis showed that the film after CO2 laser irradiation was formed flatly. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and secondary ion mass spectrometry analysis showed that uniform SiO2 film in the depth direction was obtained by CO2 Laser Annealing compared with conventional furnace annealing.
05 Jun 2013
TL;DR: In this article, a high performance and transparent ion-sensitive field-effect transistor (ISFET) was prepared by a facing-target type sputtering method using the combination of a ZnO layer for the channel and a high-k Ta2O5 layer for gate insulator.
Abstract: High-performance and transparent ion-sensitive field-effect transistor (ISFET) was prepared by a facing-target type sputtering method using the combination of a ZnO layer for the channel and a high-k Ta2O5 layer for the gate insulator. The ISFET showed a high transconductance of 2.3 mS, a low drift current of <; ±0.5 μA/h, a small gate leakage current of <; 2 nA, and a small hysteresis width of ~0.1 V. The typical pH sensitivity was ~84 μA/pH and ~55 mV/pH, and the time-constant for pH change was as small as 10 s. These parameters are comparable with those of commercially available Si ISFETs.
05 Jun 2013
TL;DR: In this paper, the expansion of the operation margin of the SRAM by optimizing the supply voltage condition is described. But the performance of the expansion is limited by the low voltage conditions of the memory cells.
Abstract: This paper describes the expansion of the operation margin of the SRAM by optimizing the supply voltage condition. To find the optimum voltage, the whole SRAM circuit is designed, which includes the worst case memory cells for the read and the write operations considering the local Vth fluctuation. By the SPICE simulation using 45-nm parameters, successful operation is obtained for wide Vth range by controlling voltages of the word line, the power line and the GND line of memory cells. As a result, the stable operation was confirmed for the wide Vth range of 0.25V-0.65V. By using these results, we can rescue a lot of LSIs which fail under the normal voltage condition.
05 Jun 2013
TL;DR: In this paper, the authors demonstrate electrophoresis of silicon micro-rods by applying asymmetric AC bias to two electrodes capped with a thin dielectric film, which significantly contribute to elimination of bubbling and contamination originating from electrochemical reactions.
Abstract: This paper demonstrates electrophoresis of silicon micro-rods by applying asymmetric AC bias to two electrodes capped with a thin dielectric film. The silicon micro-rods migrate bi-directionally when asymmetric AC bias is applied to the electrodes. The insulated electrodes significantly contribute to elimination of bubbling and contamination originating from electrochemical reactions, which makes adoption of the technique to mass production processes realistic. This technique is widely applicable to positional control of small objects including micro- and nanoscale devices.
Rohm1
TL;DR: In this article, a GaN-based E-class amplifier WPT system achieved 10W output power and η =63.5 % under the operating conditions of f = 13.56 MHz, duty=50%, and a load resistance of 10Ω.
Abstract: Enhancement-mode GaN-HEMT devices with a newly developed recessed-gate structure were fabricated. These devices were capable of operating at up to 30 MHz switching. A wireless power transmission (WPT) was adopted for a potential application of these GaN devices, because high-frequency (f) switching devices are expected to improve the power-transfer efficiency (η) of the WPT. A GaN-based E-class amplifier WPT system achieved 10W output power and η =63.5 % under the operating conditions of f =13.56 MHz, duty=50%, and a load resistance of 10Ω.
05 Jun 2013
TL;DR: In this paper, the I-V characteristic and temperature dependence of resistance in the resistive switching (RS) memory with NiO insulater was investigated and the unipolar operation mode was obtained in this device.
Abstract: Investigation of I-V characteristic and temperature dependence of resistance in the resistive switching (RS) memory with NiO insulater was performed Unipolar operation mode was obtained in this device From temperature dependence of resistance, it is suggested that the low resistance state (LRS) is metallic conduction and the high resistance state (HRS) is variable-range hopping (VRH) conduction
05 Jun 2013
TL;DR: In this article, the authors fabricated flexible ZnO-based thin-film transistors (TFTs) at room temperature and characterized the TFTs, which operated even at a bending radius of 10 mm without any significant change in their operation characteristics.
Abstract: We fabricated flexible ZnO-based thin-film transistors (TFTs) at room temperature and characterized the TFTs. ZnO films were deposited on polyethylene naphthalate (PEN) substrates by pulsed laser deposition (PLD). We succeeded in fabricating ZnO TFTs on PEN substrates. A 4-μm-long gate device had a transconductance of 21.5 mS/mm and an on/off ratio of 1.4×107. The ZnO TFTs operated even at a bending radius of 10 mm without any significant change in their operation characteristics.
05 Jun 2013
TL;DR: In this article, lowvoltage technology solutions for future IT systems are discussed, including new SOTB CMOS transistors with small variation for Vth and Ion, new non-volatile memories for cache and data storage, atom switch for logic reconfiguration, and new carbon interconnect.
Abstract: Low-voltage technology solutions for future IT systems are discussed. New SOTB CMOS transistors with small variation for Vth and Ion, new non-volatile memories for cache and data storage, atom switch for logic reconfiguration, and new carbon interconnect are discussed.
05 Jun 2013
TL;DR: It was found the separation distances of PEGylated ferritins could be controlled through ammonium acetate concentration and could be used to produce new functional devices with controlled inter-distances of NPs.
Abstract: PEGylated ferritins are used to deliver nanoparticles (NPs). It was found the separation distances of PEGylated ferritins could be controlled through ammonium acetate concentration. This method could be used to produce new functional devices with controlled inter-distances of NPs.
05 Jun 2013
TL;DR: In this paper, the dependence of annealing temperature on the ohmic contact resistance for n-type GaN layers having ohmic metal stacks of V/Al/Mo/Au and Ti/Al, Mo/Mo, and Au was investigated.
Abstract: We describe the dependence of annealing temperature on the ohmic contact resistance for n-type GaN layers having ohmic metal stacks of V/Al/Mo/Au and Ti/Al/Mo/Au. Measurement results indicated that the contact resistance for V/Al/Mo/Au with a doping level of 2×1018 cm-3 was 0.35 Ωmm after annealing at 600 °C, while that for Ti/Al/Mo/Au did not show good ohmic behaviors after annealing below 650 °C. These results indicate that V/Al/Mo/Au is a good alternative to Ti/Al/Mo/Au and is suited for low-temperature annealing. Interdiffusion of metals during annealing studied by Auger electron spectroscopy will be also discussed.
05 Jun 2013
TL;DR: Recent progress in PA designs for mobile phone applications is reviewed, with strong requirements for current reduction for a longer battery life and higher linearity for high-speed data communication.
Abstract: With strong requirements for current reduction for a longer battery life and higher linearity for high-speed data communication, progress of power amplifiers for mobile phone applications is becoming significant. This paper reviews recent progress in PA designs.