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A 64-channel surface electromyogram (EMG) measurement sheet (SEMS) with 2 V organic transistors on a 1 \mum-thick ultra-flexible polyethylene naphthalate (PEN) film is developed for prosthetic hand control. The surface EMG electrodes must satisfy the following three requirements; high mechanical flexibility, high electrode density and high signal integrity. To achieve high electrode density and high signal integrity, a distributed and shared amplifier (DSA) architecture is proposed, which enables an in-situ amplification of the myoelectric signal with a fourfold increase in EMG electrode density. In addition, a post-fabrication select-and-connect (SAC) method is proposed to cope with the large mismatch of organic transistors. The proposed SAC method reduces the area and the power overhead by 96% and 98.2%, respectively, compared with the use of conventional parallel transistors to reduce the transistor mismatch by a factor of 10. [ABSTRACT FROM PUBLISHER]

Low voltage SRAM at a near-threshold voltage has two major sources of power waste: excess bit line swing due to the random variation of transistors and dynamic power consumption of the bit line swing of non-selected columns. In order to overcome these waste power consumption issues and achieve the highest energy-efficient operation of low voltage SRAM, the new CSHBL technique and CCC techniques, which is the improved version of the CSHBL, have been proposed. An SRAM fabricated using 65 nm technology adopting the CSHBL achieved an energy consumption of 26.4 pJ/Access/Mbit, and that of 13.8 pJ/Acess/Mbit is achieved by the SRAM macro that adopted CCC with 40 nm technology. This energy consumption is lower than values in previous works. [ABSTRACT FROM PUBLISHER]

We successfully fabricated a large-area flexible strain-sensing system based on a 2-D array of organic self-bias-feedback amplifier with a signal gain of 400. The amplifier system consists of three layers: a self-assembled monolayer (SAM) capacitor matrix, a 2-D array of organic pseudo-CMOS inverters with a floating-gate structure using SAM gate dielectric, and an active matrix of organic thin-film transistors. The amplifier sheet comprises 8 \times 8 amplifier cells, with an effective size of \7 \times \7\ \cm^2. The organic transistors exhibit a mobility of 1.7 \cm^2/\V\cdot \s in the saturation regime at an operation voltage of 2 V. A strain sensor is made of a polymeric piezoelectric [polyvinylidene difluoride (PVDF)] sheet. When a cell of the PVDF sheet is touched (that is, when mechanical pressure is applied), a small signal is generated by intermolecular polarization in the PVDF. These signals are amplified by the organic amplifier circuits from 10 to 150 mV. [ABSTRACT FROM AUTHOR]

This paper presents an 80 mV startup-voltage dual-mode boost converter for energy harvesting applications. The charge-pumped pulse generator enables a startup operation of the boost converter from the input voltage of 80 mV. The threshold voltage tuned oscillator for the clock generator of the boost converter compensates for the die-to-die process variation by a hot carrier injection (HCI), thereby reducing the minimum operation voltage (VDDMIN) of the clock generator by 45% with a trimming time of 10 minutes. The proposed step-up converter achieves the lowest startup voltage without using a mechanical switch or a large transformer. [ABSTRACT FROM PUBLISHER]

This paper presents a 95 mV startup-voltage step-up DC-DC converter for energy harvesting applications. The capacitor pass-on scheme enables operation of the system from an input voltage of 95 mV without using additional off-chip components. To compensate for the die-to-die process variation, post-fabrication threshold voltage (VTH) trimming is applied to reduce the minimum operating voltage (VDDMIN) of the oscillator. Experimental results demonstrate the 34% VDDMIN reduction of the oscillator by post-fabrication VTH trimming. The proposed step-up converter achieves the lowest startup voltage in standard CMOS without using a mechanical switch or large transformer. [ABSTRACT FROM PUBLISHER]

In this paper we present User Customizable Logic Paper (UCLP) with a Sea-of Transmission-Gates (SOTG) of 2-V organic CMOS transistors. This can enable users to fabricate custom integrated circuits, by printing 200 \mu\ m wide interconnects with at-home ink-jet printers for the prototyping of large-area electronics and educational purposes. The SOTG reduces the area of the circuits in UCLP by between 11% and 85% compared with a conventional gate array architecture. [ABSTRACT FROM AUTHOR]

We have successfully fabricated a large-area flexible ultrasonic imaging system by integrating a polymeric ultrasonic-transducer array sheet with an active matrix of organic fieldeffect transistors. The ultrasonic sheet comprises 8 x 8 ultrasonic sensing cells with an effective size of 25 x 25 cm². The organic transistors exhibit mobility of 0.1 and 0.5 cm²/V · s at the low operation voltage of 1 mV and in the saturation regime, respectively. When an ac signal is applied between source and drain electrodes for the transistors with a grounded gate, the on/off ratio is larger than 104 at the carrier frequency of 40 kHz. In the linear sensing array comprising eight ultrasonic cells, crosstalk is suppressed sufficiently low, and the on/off ratio exceeds 104. Images in free space are obtained for multiple-target objects over this sheet. [ABSTRACT FROM AUTHOR]

By using state-of-the-art printing technologies and functional inks, we have demonstrated organic nonvolatile flexible random-access-memory matrices with a nondestructive read-out capability and a time-continuous current output; these functionalities have not been simultaneously achieved even by silicon-based conventional memory. A memory cell comprising three transistors becomes possible with inkjet printing and other solution-based processes, which can use ferroelectric copolymer ink comprising poly(vinylidenefluoride-co-trifluoroethylene) and insulating ink comprising polyimide precursors properly within the planer plastic substrate. A large "1 : 0" current ratio of 105 is observed in air when it is annealed at 135 °C, which is sufficiently low to be compatible with many plastic substrates. When stored in air, the "1 : 0" ratio was still 104 after 15 days and 10³ after 5 months, which is sufficient for practical applications. Furthermore, human-scale communication sheets were manufactured as the first demonstration utilizing large-area organic memories. [ABSTRACT FROM AUTHOR]

The electronics fields face serious problems associated with electric power; these include the development of ecologically friendly power-generation systems and ultralow-power-consuming circuits. Moreover, there is a demand for developing new power-transmission methods in the imminent era of ambient electronics, in which a multitude of electronic devices such as sensor networks will be used in our daily life to enhance security, safety and convenience. We constructed a sheet-type wireless power-transmission system by using state-of-the-art printing technologies using advanced electronic functional inks. This became possible owing to recent progress in organic semiconductor technologies; the diversity of chemical syntheses and processes on organic materials has led to a new class of organic semiconductors, dielectric layers and metals with excellent electronic functionalities. The new system directly drives electronic devices by transmitting power of the order of tens of watts without connectors, thereby providing an easy-to-use and reliable power source. As all of the components are manufactured on plastic films, it is easy to place the wireless power-transmission sheet over desks, floors, walls and any other location imaginable. [ABSTRACT FROM AUTHOR]

The concept of cut-and-paste customization is introduced for the first time in designing integrated circuits based on mechanically flexible organic field-effect transistors, and is applied to electronic artificial skin. The electronic artificial skin comprise of three separate integrated circuits that are a pressure-sensor array, row decoders, and column selectors to read out pressure information over a large area. All of three integrated circuits are scalable in size because the pressure-sensor array is a simple repetition of sensor cells and the row and column decoders adopt wired-NAND circuits, which enables the cut-and-paste customization in size. The physical cut-and-paste procedure is employed by cutting a part of the integrated circuits and pasting it to another integrated circuit with a connecting plastic tape. The integrated circuits are designed with a standard SPICE simulator and layout design tool, and the operation is confirmed by measurement. [ABSTRACT FROM AUTHOR]

This paper describes a low-power write scheme which reduces SRAM power by 90% by using seven-transistor sense-amplifying memory cells. By reducing the bitline swing to VDD/6 and amplifying the voltage swing by a sense-amplifier structure in a memory cell, the charging and discharging component of the power of the bit/data lines is reduced. A 64-kb test chip has been fabricated and correct read/write operation has been verified. It is also shown that the scheme can also have the capability of leakage power reduction with small modifications. Achievable leakage power reduction is estimated to be two orders of magnitude from SPICE simulation results. [ABSTRACT FROM AUTHOR]

Pseudo-CMOS inverters operating at 2 V and comprising four p-type organic transistors with ultrahigh gain are fabricated using self-assembled monolayer gate dielectrics. The inverter gain is as large as 302 at an operation voltage of 2 V, whereas the minimum operation voltage is as small as 0.5 V. The oscillation frequency of a five-stage ring oscillator comprising pseudo-CMOS inverters is 4.27 kHz at 2 V, corresponding to 23.4 \mu\s of propagation delay per stage. This is the fastest among organic circuits operating at low voltage. Pseudo-CMOS amplifier circuits show a large gain of 240 for a 3.0-mV input voltage. [ABSTRACT FROM AUTHOR]

We have demonstrated threshold-voltage control of p- and n-channel organic transistors with a floating-gate structure and self-assembled monolayer-based gate dielectrics and applied this technique to tune the switching voltage of organic complementary inverters. The threshold voltages of the p- and n-channel transistors are changed independently and systematically across a wide range from +2.4 to -1 V and from -0.3 to +1.5 V, respectively, when the program voltages of -6 V and +6 V are applied to the p- and n-channel transistors, respectively. Furthermore, we fabricated tunable organic complementary inverters, and ring oscillators whose oscillations are controlled by varying floating-gate charges. [ABSTRACT FROM AUTHOR]

We fabricated ultraflexible pentacene field-effect transistors (FETs) with a mobility of 0.5 cm2/V s and an on/off ratio of 105, which are functional at the bending radius less than 1 mm. The transistors are manufactured on a 13-μm-thick polyimide film and covered by a 13-μm-thick poly-chloro-para-xylylene encapsulation layer so that transistors can be embedded at a neutral position. This sandwiched structure can drastically suppress strain-induced changes in transistor characteristics. Furthermore, the FETs show no significant change after bending cycles of 60 000 times on inward and outward bending stresses. [ABSTRACT FROM AUTHOR]

We fabricate pentacene field-effect transistors (FETs) showing a very small degradation in performance under a continuous DC bias stress. Pentacene FETs are manufactured on polyimide films with polyimide gate dielectric layers, and then encapsulated by poly-chloro-para-xylylene passivation layers, resulting in very flexible and heat-resistant devices. When such devices are annealed at 140 °C for 12 h in a nitrogen environment, the change in their source-drain current is 3±1% even after the application of continuous DC voltage biases of VDS=VGS=-40 V for 11 h. Furthermore, their mobility is increased by postannealing effects from 0.27 cm2/V sto 0.36 cm2/V s and their on/off ratio is also increased from 103 to 106. [ABSTRACT FROM AUTHOR]

We fabricated pentacene field-effect transistors with planar-type double-gate structures, where the top- and bottom-gate electrodes can independently apply voltage biases to channel layers. The threshold voltage of organic transistors is changed systematically in a wide range from -16 to -43 V when the voltage bias of the top-gate electrode is changed from 0 to +60 V. The mobility in the linear regime is almost constant (0.2 cm2/V s) at various voltage biases of the top-gate electrode and the on/off ratio is 106. [ABSTRACT FROM AUTHOR]

We have fabricated very flexible pentacene field-effect transistors with polyimide gate dielectric layers on plastic films with a mobility of 0.3 cm2/V s and an on/off ratio of 105, and have measured their electrical properties under various compressive and tensile strains while changing the bending radius of the base plastic films systematically. We have found that the change in source-drain current with bending radius is reproducible and reversible when the bending radius is above 4.6 mm, which corresponds to strains of ∼1.4±0.1%. Furthermore, the change in source-drain current does not depend on the direction of strain versus direction of current flow. [ABSTRACT FROM AUTHOR]