Showing papers on "AND gate published in 2003"

HotLeakage: A Temperature-Aware Model of Subthreshold and Gate Leakage for Architects

Abstract: This report introduces HotLeakage, an architectural model for subthreshold and gate leakage that we have developed here at the University of Virginia. The most important features of HotLeakage are the explicit inclusion of temperature, voltage, gate leakage, and parameter variations, and the ability to recalculate leakage currents dynamically as temperature and voltage change due to operating conditions, DVS techniques, etc. HotLeakage provides default settings for 180nm through 70nm technologies for modeling cache and register files, and provides a simple interface for selecting alternate parameter values and for modeling alternative microarchitecture structures. It also provides models for several extant cache leakage control techniques, with an interface for adding further techniques. HotLeakage is currently a semi-independent module for use with SimpleScalar, but is sufficiently modular that it should be fairly easy to port to other simulators. Because sub-threshold leakage currents are exponentially dependent on temperature and voltage, because gate leakage is growing so rapidly, and because parameter variations can have a profound effect on simulation accuracy, we hope that HotLeakage will serve as a useful tool for microarchitects to more accurately evaluate issues related leakage power. HotLeakage is available for download athttp://lava.cs.virginia.edu/HotLeakage

A physical short-channel threshold voltage model for undoped symmetric double-gate MOSFETs

Abstract: A compact, physical, short-channel threshold voltage model for undoped symmetric double-gate MOSFETs has been derived based on an analytical solution of the two-dimensional (2-D) Poisson equation with the mobile charge term included. The new model is verified by published numerical simulations with close agreement. Applying the newly developed model, threshold voltage sensitivities to channel length, channel thickness, and gate oxide thickness have been comprehensively investigated. For practical device designs the channel length causes 30-50% more threshold voltage variation than does the channel thickness for the same process tolerance, while the gate oxide thickness causes the least, relatively insignificant threshold voltage variation. Model predictions indicate that individual DG MOSFETs with good turn-off behavior are feasible at 10 nm scale; however, practical exploitation of these devices toward gigascale integrated systems requires development of novel technologies for significant improvement in process control.

Sensitivity of double-gate and FinFETDevices to process variations

Abstract: We investigate the manufacturability of 20-nm double-gate and FinFET devices in integrated circuits by projecting process tolerances. Two important factors affecting the sensitivity of device electrical parameters to physical variations were quantitatively considered. The quantum effect was computed using the density gradient method and the sensitivity of threshold voltage to random dopant fluctuation was studied by Monte Carlo simulation. Our results show the 3/spl sigma/ value of V/sub T/ variation caused by discrete impurity fluctuation can be greater than 100%. Thus, engineering the work function of gate materials and maintaining a nearly intrinsic channel is more desirable. Based on a design with an intrinsic channel and ideal gate work function, we analyzed the sensitivity of device electrical parameters to several important physical fluctuations such as the variations in gate length, body thickness, and gate dielectric thickness. We found that quantum effects have great impact on the performance of devices. As a result, the device electrical behavior is sensitive to small variations of body thickness. The effect dominates over the effects produced by other physical fluctuations. To achieve a relative variation of electrical parameters comparable to present practice in industry, we face a challenge of fin width control (less than /spl sim/1 nm 3/spl sigma/ value of variation) for the 20-nm FinFET devices. The constraint of the gate length variation is about 10/spl sim/15%. We estimate a tolerance of 1/spl sim/2 /spl Aring/ 3/spl sigma/ value of oxide thickness variation and up to 30% front-back oxide thickness mismatch.

Dynamic NBTI of PMOS transistors and its impact on device lifetime

Abstract: We report a new NBTI phenomenon for p-MOSFETs with ultra thin gate oxides. We demonstrate that in a CMOS inverter circuit, the interface traps generated under NBTI stressing in a p-MOSFET (corresponding to the "high" output state of the inverter) are subsequently passivated when the gate to drain voltage switches to positive (corresponding to the "low" output state of the inverter). As a result, it was found that this "Dynamic" NBTI (DNBTI) operating in a CMOS inverter circuit prolongs significantly the device lifetime while the conventional "static" NBTI (SNBTI) underestimates the device lifetime. Furthermore, the DNBTI effect is dependent on temperature and gate oxide thickness, but independent of operation frequency. A physical model is proposed for DNBTI that involves the interaction between hydrogen and silicon dangling bonds. This finding has significant impact on the determination of maximum operation voltage as well as lifetime projection for future scaling of CMOS devices.

Flash memory with high-K dielectric material between substrate and gate

Abstract: A flash memory cell and a method of forming the same are described. The flash memory cell may include a substrate having a source and a drain, a gate element, and a dielectric layer between the substrate and the gate element. The dielectric layer includes a dielectric material having a dielectric constant that is greater than that of silicon dioxide.

Minimization of dynamic and static power through joint assignment of threshold voltages and sizing optimization

Abstract: We describe an optimization strategy for minimizing total power consumption using dual threshold voltage (Vth) technology. Significant power savings are possible by simultaneous assignment of Vth with gate sizing. We propose an efficient algorithm based on linear programming that jointly performs Vth assignment and gate sizing to minimize total power under delay constraints. First, linear programming assigns the optimal amounts of slack to gates based on power-delay sensitivity. Then, an optimal gate configuration, in terms of Vth and transistor sizes, is selected by an exhaustive local search. Benchmark results for the algorithm show 32% reduction in power consumption on average, compared to sizing only power minimization. There is up to a 57% reduction for some circuits. The flow can be extended to dual supply voltage libraries to yield further power savings.

What are the limiting parameters of deep-submicron MOSFETs for high frequency applications?

Abstract: Parameters limiting the improvement of high frequency characteristics for deep submicron MOSFETs with the downscaling process of the channel gate length are analyzed experimentally and analytically. It is demonstrated that for MOSFETs with optimized source, drain and gate access, the degradation of the maximum oscillation frequency is mainly related to the increase of the parasitic feedback gate-to-drain capacitance and output conductance with the physical channel length reduction. Optimization of these internal parameters is needed to further improve the high frequency performance of ultra deep submicron MOSFETs.

Twin monos cell fabrication method and array organization

Abstract: Presented in this invention is a fabricating method and its array organization for a high-density twin MONOS memory device integrating a twin MONOS memory cell array and CMOS logic device circuit. The invention consists of two fabrication methods, i) Simultaneous definition of memory gate and logic gate, thus improving the process integration scheme for easier and more reliable fabrication. ii) Bit line crosses word gate and control gate. The invention focuses on lowering parasitic sheet resistances to enable high speed while maintaining low manufacturing cost. The twin MONOS cell stores memory in two nitride memory cell elements underlying two shared control gates on both sidewalls of a select gate. The method is applicable to a device with a flat channel and/or a device having a step channel. Two embodiments of the present invention are disclosed.

A Probabilistic-Based Design Methodology for Nanoscale Computation

Abstract: As current silicon-based techniques fast approach their practical limits, the investigation of nanoscale electronics, devices and system architectures becomes a central research priority. It is expected that nanoarchitectures will confront devices and interconnections with high inherent defect rates, which motivates the search for new architectural paradigms. In this paper, we propose a probabilistic-based design methodology for designing nanoscale computer architectures based on Markov Random Fields (MRF). The MRF can express arbitrary logic circuits and logic operation is achieved by maximizing the probability of state configurations in the logic network. Maximizing state probability is equivalent to minimizing a form of energy that depends on neighboring nodes in the network. Once we develop a library of elementary logic components, we can link them together to build desired architectures based on the belief propagation algorithm. Belief propagation is a way of organizing the global computation of marginal belief in terms of smaller local computations. We will illustrate the proposed design methodology with some elementary logic examples.

Semiconductor integrated circuit device

Abstract: A semiconductor device includes a semiconductor layer structure, and gate, drain and source electrodes provided on the semiconductor layer structure, the gate electrode being located between the drain and source electrodes. A depletion modulating part is located between the gate electrode and the drain electrode and includes portions spaced apart from each other in a gate-width direction.

A majority-logic device using an irreversible single-electron box

Abstract: We describe a majority-logic gate device suitable for use in developing single-electron integrated circuits. The device consists of a capacitor array for input summation and an irreversible single-electron box for threshold operation. It accepts three binary inputs and produces a corresponding output, a complementary majority-logic output, by using the change in its tunneling threshold caused by the input signals; it produces a logical 1 output if two or three of the inputs are logical 0 and a logical 0 output if two or three of the inputs are logical 1. We combined several of these gate devices to form subsystems, a shift register and a full adder, and confirmed their operation by computer simulation. The gate device is simple in structure and powerful in terms of implementing digital functions with a small number of devices. These superior features will enable the device to contribute to the development of single-electron integrated circuits.

Thin film transistor array panel for a liquid crystal display and methods for manufacturing the same

Abstract: A black matrix having an opening at pixels of a matrix array in a display area, a common wire including common pads and common signal lines, and gate pads in a peripheral area, and an alignment key in outer area to align interlayer thin films are formed on an insulating substrate Red, blue and green color filters the edge of which overlap the black matrix are formed at the pixels on the insulating substrate, and an organic insulating layer covering the black matrix and the color filters and having a contact hole exposing the gate pad is formed thereon A gate wire including a gate line connected to the gate pad through the contact hole and a gate electrode connected to the gate line is formed on the organic insulating layer, and a gate insulating layer covering the gate wire is formed on the organic insulating layer A semiconductor pattern and ohmic contact layers are sequentially formed on the gate insulating layer of the gate electrode A data wire including a source electrode and a drain electrode that are made of a same layer on the ohmic contact layers and separated from each other, and a data line connected to the source electrode and defining the pixels of a matrix array by crossing the gate line is formed on the gate insulating layer A passivation layer covering the data wire and having contact holes exposing the gate pad and the data pad is formed, and a pixel wire including a pixel electrode, a redundant gate pad, a redundant data pad that are respectively connected to the drain electrode, the gate pad and the data pad through the contact holes

Method and apparatus for driving liquid crystal display device

Abstract: A driving apparatus for a liquid crystal display device includes a liquid crystal display panel having a plurality of data lines and gate lines arranged in a matrix configuration, a data driver for supplying video data to the data lines, a gate driver for supplying gate pulses to the gate lines, and a timing controller for controlling polarity of the video data by supplying a polarity inversion signal to the data driver and controlling a timing of the data driver and the gate driver according to a number of horizontal synchronization signals supplied during a data blanking period, wherein a plurality of the polarity inversion signals are different from each other.

Method for fabricating transistor gate structures and gate dielectrics thereof

Abstract: Methods are disclosed for treating deposited gate dielectric materials, in which the deposited dielectric is subjected to one or more non-oxidizing anneals to densify the material, one or more oxidizing anneals to mitigate material defects, and to a nitridation process to introduce nitrogen into the gate dielectric. The annealing may be performed before and/or after the nitridation to mitigate deposition and/or nitridation defects and to densify the material while mitigating formation of unwanted low dielectric constant oxides at the interface between the gate dielectric and the semiconductor substrate.

Two gates are better than one [double-gate MOSFET process]

Abstract: A planar self-aligned double-gate MOSFET process has been implemented where a unique sidewall source/drain structure (S/D) permits self-aligned patterning of the back-gate layer after the S/D structure is in place. This allows coupling the silicon thickness control inherent in a planar, unpatterned layer with VLSI self-alignment techniques and also gives independently controlled front and back gates. The demanding structure led to process innovations primarily in front-end CMP, where planarity within 5 nm was achieved on an 8-in diameter wafer as well as in silicided silicon source/drain sidewalls, with minimal encroachment of the silicide. Double-gate FET (DGFET) operation is demonstrated, with good transport at both interfaces. Dense circuit layouts are achieved with multifinger devices, and logic inverters with back-gate-controlled load current as well as NOR logic using the two gates of a single transistor as inputs are demonstrated.

Tri-gate and gate around MOSFET devices and methods for making same

Abstract: A triple gate metal-oxide semiconductor field-effect transistor (MOSFET) includes a fin structure, a first gate formed adjacent a first side of the fin structure, a second gate formed adjacent a second side of the fin structure opposite the first side, and a top gate formed on top of the fin structure. A gate around MOSFET includes multiple fins, a first sidewall gate structure formed adjacent one of the fins, a second sidewall gate structure formed adjacent another one of the fins, a top gate structure formed on one or more of the fins, and a bottom gate structure formed under one or more of the fins.

CMOS technology for MS/RF SoC

Abstract: Accelerated scaling of CMOS technology has contributed to remove otherwise fundamental barriers preempting its widespread application to mixed-signal/radio-frequency (MS/RF) segments. Improvements in device speed, matching, and minimum noise figure are all consistent with fundamental scaling trends. Other figures-of-merit such as linearity and 1/f noise do not scale favorably but are not considered to be roadblocks when viewed from a circuit design perspective. Furthermore, interconnect architectural scaling trends in logic technology have facilitated improvements in passive-component performance metrics. These improvements compounded with innovations in circuit design have made CMOS technology the primary choice for cost driven MS/RF applications. This paper reviews active and passive elements of CMOS MS/RF system-on-chip (SoC) technology from a scaling perspective. The paper also discusses the implications that physical phenomena such as mechanical stress and gate leakage as well as gate patterning have on technology definition and characterization.

Methods for transmitting data across quantum interfaces and quantum gates using same

Abstract: Quantum gaps exist between an origin and a destination that heretofore have prevented reliably utilizing the advantages of quantum computing. To predict the outcome of instructions with precision, the input data, preferably a qubit, is collapsed to a point value (100) within the quantum gap based on a software instruction (102). After collapse the input data is restructured at the destination (104), wherein dynamics of restructuring are governed by a plurality of gap factors as follows: computational self-awareness; computational decision logic; computational processing logic; computational and network protocol and logic exchange; computational and network components, logic and processes; provides the basis for excitability of the Gap junction and its ability to transmit electronic and optical impulses, integrates them properly, and depends on feedback loop logic; computational and network component and system interoperability; and embodiment substrate and network computational physical topology.

Non-volatile devices, and electronic systems comprising non-volatile devices

Abstract: The invention includes non-volatile memory and logic devices associated with crystalline Si/Ge. The devices can include TFT constructions. The non-volatile devices include a floating gate or floating plate over the Si/Ge, and a pair of source/drain regions. The source/drain regions can extend into the Si/Ge. The memory or logic devices further include an insulative material over the floating gate or plate, and a control gate separated from the floating gate or plate by the insulative material. The crystalline Si/Ge can have a relaxed crystalline lattice, and a crystalline layer having a strained crystalline lattice can be formed between the relaxed crystalline lattice and the floating gate or plate. The devices can be fabricated over any of a variety of substrates. The floating plate option can provide lower programming voltage and orders of magnitude superior endurance compared to other options.

All-optical AND gate by use of a Kerr nonlinear microresonator structure

Abstract: We numerically demonstrate the feasibility of constructing an all-optical AND gate by using a microresonator structure with Kerr nonlinearity The gate is much smaller than similar AND gates based on Bragg gratings and has lower power requirements

Class-E High-Efficiency RF/Microwave Power Amplifiers: Principles of Operation, Design Procedures, and Experimental Verification

Abstract: Class-E power amplifiers [1]–[6] achieve significantly higher efficiency than for conventional Class-B or -C. Class E operates the transistor as an on/off switch and shapes the voltage and current waveforms to prevent simultaneous high voltage and high current in the transistor; that minimizes the power dissipation, especially during the switching transitions. In the published low-order Class-E circuit, a transistor performs well at frequencies up to about 70% of its frequency of good Class-B operation (an unpublished higher-order Class-E circuit operates well up to about double that frequency). This paper covers circuit operation, improved-accuracy explicit design equations for the published low-order Class E circuit, optimization principles, experimental results, tuning procedures, and gate/base driver circuits. Previously published analytically derived design equations did not include the dependence of output power (P) on load-network loaded Q (Q L ); as a result, the output power was 38% to 10% less than expected, for Q L values in the usual range of 1.8 to 5. This paper includes an accurate new equation for P that includes the effect of Q L .

Damascene double-gate FET

Abstract: A double-gate field effect transistor (DGFET) is provided using a damascene-like replacement gate processing step to create sidewall source/drain regions, oxide spacers and gate structures inside a previously formed trench. The damascene-like replacement gate processing step allows for the fabrication of a tapered transistor body region having a thicker body under the contacts which reduces access resistance.

Simultaneous subthreshold and gate-oxide tunneling leakage current analysis in nanometer CMOS design

Abstract: In this paper we develop a fast approach to analyze the total leakage power of a large circuit block, considering both gate leakage, I/sub gate/, and subthreshold leakage, I/sub sub/. The interaction between I/sub sub/ and I/sub gate/ complicates analysis in arbitrary CMOS topologies. We propose simple and accurate heuristics to quickly estimate the state-dependent total leakage current considering the interaction between I/sub sub/ and I/sub gate/. We apply this method to ISCAS benchmark circuits in a projected 100 nm technology and demonstrate excellent accuracy compared to SPICE simulation with a 20,000X speedup on average.

Minimization of dynamic and static power through joint assignment of threshold voltages and sizing optimization [logic IC design]

Abstract: We describe an optimization strategy for minimizing total power consumption using dual threshold voltage (Vth) technology. Significant power savings are possible by simultaneous assignment of Vth with gate sizing. We propose an efficient algorithm based on linear programming that jointly performs Vth assignment and gate sizing to minimize total power under delay constraints. First, linear programming assigns the optimal amounts of slack to gates based on power-delay sensitivity. Then, an optimal gate configuration, in terms of Vth and transistor sizes, is selected by an exhaustive local search. Benchmark results for the algorithm show 32% reduction in power consumption on average, compared to sizing only power minimization. There is up to a 57% reduction for some circuits. The flow can be extended to dual supply voltage libraries to yield further power savings.

Switching theory

Abstract: Switching theory is the abstract mathematical formalization used in the logic design of digital networks. It is so called because, when it was first developed by Claude Shannon (q.v.) in 1938, most logic networks were implemented using switches and electromechanical devices such as relays. Modern logic networks are usually constructed using electronic integrated circuits comprising networks of logical elements such as inverters, AND gates, and OR gates. These elements operate on binary signals; they are constrained to take on only two different voltage values (such as 0 or 5 volts). Switching theory used a two-valued Boolean algebra (sometimes called Switching algebra) as a notation to represent the operation of such logic networks. The two algebraic values are most often represented as "0" and "1," although "T" and "F" are sometimes used to emphasize the relation to propositional logic. The correspondence between the algebraic symbol used to represent a signal and the voltage present is arbitrary, although the positive logic convention in which the algebraic 1 represents the more positive voltage signal is now most common. Each input or output signal of a logic network is represented by a Boolean variable. Boolean algebra has three basic operations: inversion, logical addition, and logical multiplication; these operations are implemented directly by logic gates called inverters, OR gates, and AND gates. The symbols most often used to represent these gates are shown in Fig. 1. The output of an inverter always takes on the value opposite to the value of its input., The output of an OR gate is always equal to 1 unless all of its inputs are equal to 0, in which case the output is 0. The output of an AND gate is always equal to 0 unless all of its inputs are equal to 1, in which case the output is 1.

Simulation study of single-event gate rupture using radiation-hardened stripe cell power MOSFET structures

Abstract: A two-dimension simulation study of single-event gate rupture (SEGR) in radiation-hardened stripe cell power MOSFETs is reported. Simulations are performed on stripe-cell structures employing three different neck widths. A simple methodology is presented showing how these simulations can be used to approximate the drain and gate biases required to induce SEGR. These biases are then compared with the experimental data and found to be in good agreement. By means of simulations, we investigated the effects of various physical mechanisms and input parameters, which are likely to be important in SEGR and found that impact ionization plays a crucial role in the process. The simulations show that the N+ source and P+ plug are critical to the hardened design (narrower neck widths). Clearly, simulations could become a useful tool in evaluating certain design and processing variations.