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The authors of the International Technology Roadmap for Semiconductors (1)--the industry consensus set of goals established for advancing silicon integrated circuit technology-have challenged the computing research community to find new physical state variables (other than charge or voltage), new devices, and new architectures that offer memory and logic functions (1-6) beyond those available with standard transistors. Recently, ultra-dense resistive memory arrays built from various two-terminal semiconductor or insulator thin film devices have been demonstrated (7-12). Among these, bipolar voltage-actuated switches have been identified as physical realizations of 'memristors' or memristive devices, combining the electrical properties of a memory element and a resistor (13,14). Such devices were first hypothesized by Chua in 1971 (ref. 15), and are characterized by one or more state variables (16) that define the resistance of the switch depending upon its voltage history. Here we show that this family of nonlinear dynamical memory devices can also be used for logic operations: we demonstrate that they can execute material implication (IMP), which is a fundamental Boolean logic operation on two variables p and q such that pIMPq is equivalent to (NOTp)ORq. Incorporated within an appropriate circuit (17,18), memristive switches can thus perform 'stateful' logic operations for which the same devices serve simultaneously as gates (logic) and latches (19) (memory) that use resistance instead of voltage or charge as the physical state variable., In 1936, more than ten years before the discovery of the transistor, Claude Shannon invented digital electronics during his Master's thesis (20) research. He showed that the basic Boolean logic [...]

Oxygen tension in mammalian cell culture can profoundly affect cellular differentiation, viability, and proliferation. However, precise measurement of dissolved oxygen in real time remains difficult. We report a new noninvasive sensor that can accurately measure oxygen concentration during cell culture while being compatible with live-cell imaging techniques such as fluorescence and phase contrast microscopy. The sensor is prepared by integrating the porphyrin dye, Pt(II) meso-tetrakis(pentafluorophenyl)porphine (PtTFPP) into polydlmethylsiioxane (PDMS) thin films. Response of the sensor in the presence of oxygen can be characterized by the linear Stern-Volmer relationship with high sensitivity ([K.sub.sv] = 584 [+ or -] 71 [atm.sup.-1]). A multilayer sensor design, created by sandwiching the PtTFPP-PDMS with a layer of Teflon AF followed by a second PDMS layer, effectively mitigates against dye cytotoxicity while providing a substrate for cell attachment. Using this sensor, changes in oxygen tension could be monitored in real-time as attached cells proliferated. The oxygen tension was found to decrease due to oxygen consumption by the cells, and the data could be analyzed using Fick's law to obtain the per-cell oxygen consumption rate. This sensor is likely to enable new studies on the effects of dissolved oxygen on cellular behavior. 10.1021/ac9013379

A study was conducted to examine the above-threshold characteristics of amorphous silicon Zn-based oxide (ZnO) thin-film transistors (TFTs) using exponential tail-state distribution model. Findings suggested that an exponential tail-state distribution model could be used to explain the above-threshold behavior of ZnO TFTs.

The article studies the relationship amongst the structural properties of microcrystalline silicon and the performance of high-mobility microcrystalline-silicon thin-film transistors (TFTs). Findings suggest that the microcrystalline-silicon-TFT-based complementary-metal-oxide-semiconductor inverters with high voltage gains will be exceeding 22.

A novel approach is described for making high-performance CMOS at low temperatures. CMOS inverters and fully functional 51-stage ring oscillators are fabricated in this process and this process is used for large-area TFT electronics as well as a functional stack layer in 3-D integration.

An analytical model is developed for studying the transfer characteristics of a polycrystalline silicon thin-film transistor (TFT) with an undoped channel. The transition between the pseudo-subthreshold and the turn-on regimes of operation of a TFT is characterized by a transition voltage [V.sub.pt], at which the extrapolated drift mobility in the grains is equal to the extrapolated effective grain-boundary mobility.

The performance of resistance random access memory (RRAM) devices based on spin-coated sol-gel-derived zinc oxide (ZnO) thin films is examined. The devices are fabricated on a flexible plastic substrate and have displayed excellent durability upon repeated bending tests, thus showing their potential for flexible low-cost memory devices.

Bistable shape memory actuators were fabricated by microsystem technology processes and characterized with regard to their use in tactile graphic displays. The actuators were realized as sputter-deposited buckled metallic thin-film carriers, having structured Ti-Ni-Cu and Ti-Ni-Hf shape memory alloys on the top and at the bottom, respectively. They were sputtered on wavy-structured substrate and had lateral dimensions ranging from 2.2 to 3.5 mm in width and from 1 to 3 mm in length. The actuators were switched with voltages in the range of 0.2 to 0.8 V and with currents in the range of 0.2 to 0.8 A. A force of 2.2 mN with a displacement of 0.7 mm was reached. To improve the performance further, a special test setup was developed. The bistable actuators in it were sputtered on a planar substrate with lateral dimensions ranging from 6 to 8 mm in width and from 3 to 6 mm in length. These actuators were switched with actuation voltages in the range of 0.6 to 1.6 V and with currents in the range of 0.6 to 1.8 A. Thus, a force of 16 mN with a displacement of 1.2 mm was reached. [2007-0261] Index Terms--Bistable actuators, shape memory alloys (SMAs), tactile display, thin-film actuators.

In neural prosthetic systems, a low-impedance electrode-tissue interface is important for maintaining signal quality for recording, as well as effective charge transfer for stimulation. However, neural microelectrodes often have high impedance due to their small surface areas. In this paper, we present a simple method of increasing their effective surface areas by introducing nanostructures on the electrode sites. The method combines photolithography and electron-beam evaporation with a locally patterned anodized porous alumina template to integrate Au-nanorod arrays on the flexible thin-film microelectrode, which can significantly increase the effective surface area and decrease impedance due to its 3-D and compact nanostructures. Moreover, the geometrical and electrical properties of Au-nanorod electrodes were demonstrated and compared with conventional planar microelectrodes by using a scanning electron microscope and an impedance spectroscopy system. Experimental results showed that approximately 25 times lower interface impedance was achieved for this nanostructured microelectrode. Such Au-nanorod integrated microelectrode arrays will be a promising tool for neural engineering. [2008-0136] Index Terms--Electron-beam evaporation, flexible, neural electrode, porous alumina.

An analytical model is described that has successfully unified the standard Schottky and arbitrarily shallow p-n junctions. The ultrashallow p-n junctions could vary from the features of standard Schottky diodes to standard deep p-n junctions depending on the junction depth and electrical characteristics.

A detailed study related to the factors that affect the photo leakage current like bias condition, temperature, and defect states of low-temperature polycrystalline-silicon (LTPS) thin-film transistors (TFTs) is reported. The results revealed that the mechanisms of the photosensitivity for the LTPS TFT are closely related to the different defect distribution or density in the grain boundary.

A low-temperature technology is described for the fabrication of a polycrystalline silicon (poly-Si) thin-film transistor (TFT) with self-aligned metal electrodes (SAMEs). The effects of aluminum thickness on aluminum-induced crystallization (AIC) annealing temperature and time on the performance of a SAME poly-Si TFT are described.

Low-temperature multichannel poly-Si thin-film transistors (TFTs) are prepared by KrF excimer laser annealing with a channel width that is comparable to or smaller than the poly-Si grain size. It is shown that the TFTs with ten 40-nm-wide multichannels have superior electrical characteristics, including a higher on/off current ratio, lower leakage current, less grain boundary defects density and a better subthreshold swing.

The fabrication and characterization of the advanced amorphous silicon thin-film transistors with a bilayer structure for both the active and gate dielectric films is discussed. Results suggest the achievement of high thin-film transistor stability even under the presence of a high channel current.

Different [N.sub.2]O plasma power treatments were used for developing high-k [Pr.sub.2][O.sub.3] poly-Si thin-film transistors (TFTs). High effective carrier mobility, high driving current, small subthreshold slope and high ON/OFF current ratio are observed.

This paper presents a new source-follower type analog buffer for active-matrix liquid crystal displays applications, which exhibits high immunity to the threshold voltage variations of the polysilicon (poly-Si) thin-film transistors (TFTs). The functionality of the buffer was verified through simulations. In order for the simulations to be realistic, parameters extraction from fabricated poly-Si TFTs were used. Index Terms--Active-matrix liquid crystal displays (AMLCDs), analog buffer, column driver, low-temperature (LT) polysilicon (poly-Si) thin-film transistors (TFTs), pixel array.

The realization of transferable single-crystal elastically strained Si/SiGe/Si nanomembranes (SiNMs) and the demonstration of high-mobility strained-channel MOS thin-film transistors (TFTs) on elastically strain-sharing single SiNMs are described. The results have shown that the transferable and thermally stable single-crystal elastically strain-sharing SiNMs are very good active materials for high-speed device application with a simple and scalable transfer method.

A compact model for poly-Si thin-film transistors (TFTs) leakage current including the Poole-Frenkel (PF) effect is presented. Findings reveal the suitability of the model for circuit simulation due to its analytical nature.

Broadband optical monitoring for thin-film filter manufacturing is more and more developed thanks to better performances of spectrometers with array detectors. We compare this optical monitoring with turning point monitoring and quartz monitoring of different designs. The sensitivity to thickness errors and to refractive index errors is evaluated. We show that real time determination of deposited thickness is a valuable criterion. We also present our experimental setup of transmittance and reflectance broadband optical monitoring. The use of a 400-1000 nm range combined with a signal-to-noise ratio of ~2500 in transmittance and 1000 in reflectance permits us to expect the manufacturing of high-performance non-quarter-wave designs. A first manufacturing of an 18-layer non-quarter-wave high-pass filter is provided. OCIS codes: 310.0310, 310.1860, 310.1620, 310.6860.

The article investigates Pentacene-based planar- and vertical-type organic thin-film transistors (OTFTs).

A chemical bath deposition process for zinc oxide (ZnO) deposition is used for demonstration of solution-processed transparent ZnO transistors. The process results in high mobility of 3.5 [cm.sub.2]/V.s with on-off ratios of approximately [10.sup.5].

The effects of static stress were investigated by the aid of numerical simulations and using two types of procedures namely the on stress and the hot carrier stress. Results show that the variations of trap state density into the whole polysilicon layer and not only near the drain junction are responsible for the degradation of thin-film transistors (TFTs) performances in both types of stress and that the interface trap states play a negligible role compared to the bulk trap states.

The threshold-voltage [V.sub.T] compensation circuit that consists of two thin-film transistors and one capacitor (2T1C) for active-matrix organic light-emitting diode displays is proposed and simulated. The simulation result indicates that it compensates the threshold voltage of the driver thin-film transistor with high accuracy and the circuit would contribute to the improvement of the production yield because the only minimum electrical parts are introduced in a pixel with the function of pixel-level compensation and with a large aperture ratio.

A novel method has been used for accurately measuring low voltage signals (~[10.sup.-4] V) associated with inductance changes of bilayer thin-film sensors under bending stress. In this paper the architecture of the system is first presented, and then the design ideas and key technologies are followed. Initially, the frequency modulated signals were simulated with superimposed noise signals to test the demodulation performance of the written program. From the results, the expected output of the program was confirmed. Following this, the frequency modulation technique was used with actual sensor signals to measure the displacement of a bilayer thin film sensor. The results from the acquisition were compared with a previously developed amplitude modulation based setup, and it proved that the frequency modulation system provided a robust and accurate solution to evaluate magnetostrictive materials and their application in magnetic sensors. Index Terms--Amorphous magnetic films, frequency modulation, magnetic sensors, magnetostriction.

Various experiments and studies are conducted to study the role of order and disorder on the electronic performance of n-type ionic oxides, which are used as active or passive layers in thin film transistors (TFTs) processed at the room temperature. The analysis shows that the disorder does not affect the carrier mobility of the transistors much, as compared to that of semiconductors, though the electrical properties are found to be highly dependent on the oxygen vacancies.

Several electrical in situ and ex situ measurements are conducted to study the influence of various environmental conditions, like dry oxygen and moisture on the electronic transport and device stability of the polycrystalline pentacene transistors. The analysis reveals that such conditions inhibits the injection of holes in the highest occupied molecular orbital level of the film, which further leads to an apparent reduction of the charge carrier mobility, as well as the threshold voltage.

A combination of solvent cleaning and oxygen plasma cleaning processes is used to study and explain the effects of Si[O.sub.2] dielectric preparation on interfacial trap density in pentacene-based organic thin-film transistors. The reduction in the organic contamination at the semiconductor/dielectric interface following the plasma cleaning, leading to a reduction in the trapping states, is found to improve the threshold voltage of the devices.

The different ways of making high-performance transistors by using semiconductors that are defective, unstable and have low earlier mobilities are described. The unstable and defective semiconductor, hydrogenated amorphous silicon is used to show that the high-performance thin-film transistors can be obtained by using the source-gated concept.

The heat generation of a low-temperature polycrystalline thin-film transistor in pulse operation is analyzed and a technique is proposed for accurately measuring its thermal temperature in high-frequency operation. The degradation in pulse operation is investigated by pulse signal input into the p-channel low-temperature p-Si thin-transistor (TFT) and the relationship between the thermal temperature and the degradation in the pulse operation is discussed.

The device degradation behaviors of typical-sized n-type metal-induced laterally crystallized polycrystalline silicon thin-film transistors are investigated under hot-carrier (HC) stress and self-heating (SH) stress. The results have shown that the device degradation is the consequence of HC induced defect generation locally at the drain side under HC stress.

A new source-follower-type analogy buffer is proposed for active-matrix displays, which are designed by using low-temperature polysilicon thin-film transistors (TFTs). The new buffer does not need storage capacitor for the threshold-voltage variation cancellation, thereby leading to high-speed operation.

We report on glass etching transfer processes to obtain thermally stable large-size TFT flexible substrates on plastic film bases. The transfer processes include high-pressure jet etching that allows us to achieve good etch-rate uniformity over the large area and the utilization of an adhesive having a low elastic modulus. From the experiments and simulations, we find that using an adhesive having a low elastic modulus is effective in reducing bend of the flexible substrate under thermal stresses. The simulations also predict that the reduction in the bend corresponds to the reduction in the principal stress of the adhesive, leading to the suppression of the film peeling off from the thinned glass. Using the transfer processes, we have successfully fabricated thermally stable TFT flexible substrates (300 mm x 350 mm x 200 [micro]m) that have satisfactory electrical characteristics. Index Terms--Adhesive, elastic modulus, flexible substrate, glass etching, thin-film transistor, transfer process.

A study was conducted to fabricate poly-Si-oxide-nitride-oxide-silicon (SONOS)-type poly-Si-thin-film transistor (TFT) memories employing hafuium silicate as the trapping layer with low-thermal budget processing. The fabricated memories exhibited good performance in terms of relatively large memory window, high program/erase speed (1 ms/10 ms), long retention time, and 2-bit operation.

A concept for incorporating dispersion compensation into a saturable absorber mirror is discussed. The concept paves the way for fully integrated vertical semiconductor femtosecond lasers and can also be applied in solid state lasers and femtosecond fiber lasers.

The transmission ellipsometric function (TEF) of a film-substrate system relates the polarization change, upon transmission, of an electromagnetic wave obliquely incident on, and transmitted through, a filmsubstrate system. The behavior of the TEF depends on the category of the film-substrate system: negative, zero, or positive. The category is determined by the sign of [N.sub.1] - \[[square root of][N.sub.0][N.sub.2]: negative for a negative film-substrate system, zero for a zero system, and positive for a positive system. We discuss the behavior of the TEFs of the two transparent nonnegative film-substrate systems, zero and positive. We describe the TEF as two successive transformations and analyze its behavior as the angle of incidence and film thickness of the film-substrate system are changed. We use the constant-angle-of-incidence contours and constant-thickness contours to analyze and utilize that behavior. From the analysis and understanding of the behavior of the TEF, and from the definition of a polarization device as a film-substrate system that introduces prescribed polarization changes, we discuss the design of all possible types of polarization devices using either of the two systems. We present a design formula for each. We also present a general formula that is used for the design of any of the devices. Thin-film coatings are treated as polarization devices for the purposes of our discussion. We conclude with a brief discussion of suggested practical modifications to, and simplifications of, ellipsometric memory, which is an interesting application of polarization devices for which there is a patent pending. OCIS codes: 310.1620, 230.1150, 120.2130, 000.3870.