Reduction In Transistor Count Research Articles

CNTFET-based digital arithmetic circuit designs in ternary logic with improved performance

Ternary logics are more desirable than the binary logic because it offers high speed operations and large density of information in digital logic systems. The carbon nanotube field-effect transistors (CNTFETs) are considered as better option for designing the ternary circuits because it provides the multiple threshold voltages by changing nanotube diameter. The complex arithmetic schematics such as adders and multipliers are important circuits in many VLSI applications. The ternary half-adder (THA) and multiplier (TMUL) designed using the Stanford 32 nm CNTFET are proposed in this study. The proposed THA and TMUL uses 41 and 33 CNTFETs and that resulting in a 54.44 % and 45 % reduction in transistor count, which plays major role for delay and power optimization. As a result, the proposed THA shows 37.01 %, 14.07 %, and 45.87 % improvement in delay, power, and energy, whereas TMUL shows 30.48 %, 6.64 %, and 36.74 % improvement in delay, power and energy, respectively, compared to existing circuits. The proposed THA and TMUL are developed using HSPICE with 0.9 V as a supply voltage.

A review of crosstalk polymorphic circuits and their scalability

Using a control variable, the functionality of Polymorphic circuits can be modified, making them adaptable and useful for reconfiguring circuit behavior — all the way from gate level to system level. State-of-the art polymorphic circuits are based on custom non-linear circuit design or emerging devices such as ambipolar FET, configurable magnetic devices etc. While some of these approaches are inefficient in performance, others involve exotic devices. The Crosstalk computing based polymorphic circuits offer a fresh perspective. In Crosstalk, the interconnect interference between nanoscale metal lines is intentionally engineered to exhibit the programmable Boolean logic behavior. This approach relies on the coupling between metal lines and not on the transistors for computing, resulting in better scalability, security by obscurity, and fault tolerance by reconfiguration. Our novel approach is backed by the mathematical formulation that conveys the rationale to generalize and achieve a wide variety of polymorphic circuits. Our experiments, including design, simulation, and Power Performance Area (PPA) characterization results indicate that crosstalk circuits provide significant improvement in transistor count (about 3x), switching energy (2x), and speed (1.5x) for polymorphic logic circuits. In the best-case scenario, the transistor count reduction is 5x. This paper presents Crosstalk computing’s fundamentals, polymorphism and the scalability aspects to compete/co-exist with CMOS for digital logic implementations below 10 nm. Our scalability study uses Open Source 7 nm PDK, considers all process variation aspects and accommodates worst-case scenarios. The study results for various benchmark circuits show that the Crosstalk technology is a viable alternative to CMOS for digital logic implementations below 10 nm, having 48% density, 57% power, and 10% performance gains over equivalent CMOS counterparts. Finally, we compare Crosstalk Polymorphic Circuit design technique with similar approaches described in related works and discuss its features and constraints.

Reconfigurable Multifunctional van der Waals Ferroelectric Devices and Logic Circuits.

Emerging reconfigurable devices are fast gaining popularity in the search for next-generation computing hardware, while ferroelectric engineering of the doping state in semiconductor materials has the potential to offer alternatives to traditional von-Neumann architecture. In this work, we combine these concepts and demonstrate the suitability of reconfigurable ferroelectric field-effect transistors (Re-FeFETs) for designing nonvolatile reconfigurable logic-in-memory circuits with multifunctional capabilities. Modulation of the energy landscape within a homojunction of a 2D tungsten diselenide (WSe2) layer is achieved by independently controlling two split-gate electrodes made of a ferroelectric 2D copper indium thiophosphate (CuInP2S6) layer. Controlling the state encoded in the program gate enables switching between p, n, and ambipolar FeFET operating modes. The transistors exhibit on-off ratios exceeding 106 and hysteresis windows of up to 10 V width. The homojunction can change from Ohmic-like to diode behavior with a large rectification ratio of 104. When programmed in the diode mode, the large built-in p-n junction electric field enables efficient separation of photogenerated carriers, making the device attractive for energy-harvesting applications. The implementation of the Re-FeFET for reconfigurable logic functions shows how a circuit can be reconfigured to emulate either polymorphic ferroelectric NAND/AND logic-in-memory or electronic XNOR logic with a long retention time exceeding 104 s. We also illustrate how a circuit design made of just two Re-FeFETs exhibits high logic expressivity with reconfigurability at runtime to implement several key nonvolatile 2-input logic functions. Moreover, the Re-FeFET circuit demonstrates high compactness, with an up to 80% reduction in transistor count compared to standard CMOS design. The 2D van de Waals Re-FeFET devices therefore exhibit promising potential for both More-than-Moore and beyond-Moore future of electronics, in particular for an energy-efficient implementation of in-memory computing and machine learning hardware, due to their multifunctionality and design compactness.

Nonuniform Compressive Sensing via Ohmic Voltage Attenuation: A Memristive Crossbar Design Approach Leveraging Intrinsic Computation

Compressive sensing (CS) is a promising technique for transmitting signals in power-critical applications such as Internet of Things (IoT) devices. Nonuniform CS optimizes this process by adjusting sampling frequency based on the relative importance levels characterized by the signal of interest. Recent advances have yielded energy-efficient hardware implementations of CS sampling, leveraging spin-based crossbar architectures for in-memory vector-matrix multiplication and through the use of probabilistic bit (p-bit) devices to generate tunable random outputs for writing the array. Thus, a region of interest is generated via column-ordered density of on-state devices. Herein, we propose a simple design for supplying inputs to the p-bit devices, based on Ohmic voltage attenuation occurring along the word lines of the crossbar array. The technique embeds some required computations to be conducted intrinsically by the cross-points of the memristive array, thus bypassing overheads of conventional instruction execution and eliminating the need for costly hardware components, such as lookup tables (LUTs) and data converters. The design is shown to be robust for various array sizes and parasitics while generating the appropriate tuning signals within a single clock cycle duration of 1.6 ns, and at an energy overhead of 333 fJ. Compared with a standard approach using LUTs and digital to-analog converters, the design herein achieves a 583-fold reduction in energy and 23-fold reduction in transistor count.

Crosstalk-Computing-Based Gate-Level Reconfigurable Circuits

The functionality of polymorphic circuits can be altered using a control variable. Owing to the multifunctional embodiment in polymorphic circuits, they are helpful to reconfigure circuit behavior from the gate level to the system level, either on the fly or off-line. The polymorphic circuit approaches available in the literature are either based on custom nonlinear circuit designs or special emerging devices, such as ambipolar FET and configurable magnetic devices. While some of these approaches are inefficient in performance, the other approaches involve exotic devices. We have proposed a novel polymorphic circuit design approach based on crosstalk (CT) computing, where we leverage deterministic signal interference between nanometal lines for logic computation and reconfiguration. In this article, we elaborate upon the polymorphic circuit design in CT computing through mathematical formulation, which conveys the rationale to generalize and achieve a wide variety of polymorphic circuits, and then demonstrate a comprehensive list of polymorphic circuit designs. In addition, all circuits are characterized and benchmarked against CMOS circuit implementations to gauge the benefits. Finally, we compare the CT polymorphic circuit approach with other approaches in the literature and highlight its unique features and limitations. The ability to design a wide range of polymorphic logic circuits (basic and complex logics) compact in design and minimal in transistor count is unique to CT computing, which leads to benefits in the circuit power, performance, and area (PPA). Our circuit designs, simulation, and PPA characterization results show that the polymorphic CT circuits provide <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> improvement in transistor count, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> improvement in switching energy, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.5\times $ </tex-math></inline-formula> improvement in speed for polymorphic logic circuits. In the best-case, the transistor count reduction is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> .

Transistor Count Reduction Technique for Clockfree Null-convention Arithmetic Logic Circuits

Null Convention Logic (NCL) is a robust clock-less technique for designing asynchronous delay-insensitive circuits. The traditional complementary metal oxide semiconductor (CMOS) approach is often used for designing NCL circuits, which tends to occupy a large area. To address this issue, a low power design technique Gate Diffusion Input (GDI) is introduced for designing the NCL circuits. This GDI design methodology is the promising alternative for the static CMOS designs, which allows the reduction in area and power consumption while maintaining the low complexity of the logic design. In this paper, a novel GDI based NCL designs are proposed and designed. However, the voltage swings in the GDI approach leads to the considerable amount of voltage drop at the output. This limitation is addressed by using low threshold transistors where a voltage drop is expected, and high threshold transistors are used for the regenerative inverters at the output. The proposed approach has been verified by designing the NCL Ripple Carry Adder (RCA), Unpipelined multiplier, pipelined multiplier and Unpipelined ALU by using the GDI technique. These models are designed and simulated using Cadence Virtuoso and an average of 13.5 % reduction in the transistor count is observed for these GDI based NCL models when compared to the CMOS models.

An Efficient Ultra-Low-Power and Superior Performance Design of Ternary Half Adder Using CNFET and Gate-Overlap TFET Devices

This paper presents a novel ultra-low power yet high-performance device and circuit design paradigm for implementing ternary logic based circuits using Gate-Overlap Tunnel FETs (GOTFETs) and Carbon Nanotube FETs (CNFETs). One of the distinguishing novelty reported in this work is the introduction of an innovative GOTFET device, which exhibits more than double the on-currents I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> and less than 1/10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> the off-currents I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</sub> of equivalent, equally-sized mosfets at the same technology node. Most of the ternary logic designs reported earlier in the literature encode ternary bits into binary for combinational functionality and then use an Encoder to get back ternary output. Unlike the earlier designs, this paper presents a novel and significantly more efficient approach of directly designing ternary logical functions with Low V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> Transistors (LVT) and High V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> Transistors (HVT) using CNFET and GOTFET technologies. The new approach simplifies the design and reduces the required transistor count & interconnects, thereby reducing the delays and power consumption. The proposed Ternary Half Adder (THA) circuit, designed using CMOS, enables a 52% reduction in transistor count compared to the conventional CMOS designs available in the literature. The THA implemented with CNFET exhibits 27 ps (87% lower delay than similar CMOS design and consumes 2.4 μW power (11% lower than CMOS). On the other hand, CGOT THA exhibits 101 ps (51% lower delay than similar CMOS design) and consumes merely 1.26 μW power (53% lower than CMOS, in ultra-low power regime). The overall decrease in the Power Delay Products (PDPs) are 88% and 77%, respectively, in the proposed CNFET and CGOT THA circuits compared to the CMOS THA.

Comprehensive Analysis and Optimization of Reliable Viterbi Decoder Circuits Implemented in Modular VLSI Design Logic Styles

The Viterbi Algorithm is a recursive optimal solution for estimating the most likely state sequence of discrete-time finite-state Markov process and Hidden Markov Models (HMM) observed in memoryless noise. The Viterbi algorithm is extensively used for decoding convolutional codes, in the constraint length k that encompasses its use in digital communications specifically in satellite and cellular communications. Storage devices to speed up access, speech synthesis and recognition technologies use the Viterbi algorithm or its variants. In this paper low-power, high-speed and reduced transistor count Viterbi decoding circuits with enhanced error detection capabilities are designed and implemented with signature-based error detection schemes in three design logic styles primarily Conventional CMOS, Hybrid logic and GDI. The significance of the work is the upshot of realizing low latency and low power dissipation with high reliability in the iterative process of finding the least path metric by superseding the subtractor in CSA & PCSA circuits with an optimized comparator. When evaluated against the Traditional/Benchmark CSA & PCSA circuits, the Conventional CMOS design approach attains low power consumption and high accuracy with a reduction in average power dissipation by 4.69% and 3.83% and an improvement in delay performance by 7.89% and 3.79% respectively, with a tradeoff for high area utilization. Whereas, the GDI design approach results in an extreme reduction of transistor count by 71.52% and 74.94% with a weaker logic swing for CSA & PCSA units respectively, complimented by an increase in power dissipation (approximately multiplied by a factor of 5) and deterioration in delay performance by one order of magnitude. The Hybrid logic stages CSA & PCSA units that are 32.52% and 9.27% faster and achieve optimization in area utilization by 48.68% and 51.09% respectively, at the expense of elevated power dissipation by one order of magnitude. All the circuits were designed and simulated using GPDK 90 nm technology libraries on Cadence Design Suite 6.1.6 platform at 27 °C temperature on 1.2 V supply-rail and SPICE codes were generated as well.

A Competent Multiplier Architecture with Reduced Transistor Count for Radix -2 Butterfly Computation of Fast Fourier Transform

Multiplication is the elementary process for computing the butterfly in Fast Fourier Transform. A formal multiplication task requires an extensively additional hardware means and processing time in multiplication operation to a certain degree more than in addition and subtraction. In this work, architecture for multiplier is proposed which requires less space and works faster comparatively with other basic multiplier structures. The “UrdhvaTiryakbhyam” scheme offered by Vedic Mathematics is utilized to speed up the multiplication process. In addition, the reduction in transistor count is achieved by substrate biasing. Further the architecture is simulated in ORCAD software to analyse the area requirements of the Butterfly structure for computing Fast Fourier Transforms. The simulated results show that there is considerable reduction in transistor count and operating speed which makes the proposed multiplier a competent one with the standard multiplier architecture.

Digital System Design Using Standard NeuMOS Cells Applied in ADAS

The design and implementation of digital systems with external configuration circuit–SHL (software–hardware–logic)—with standard cells based on floating-gate transistor (NeuMOS) and the implementation of the floating-gate potential diagram (FPD) to obtain Boolean functions are presented. External circuit configuration for designing digital systems of two and four bits reduces the number of transistors, as well as interconnection, and this can increase the speed of data processing; these results are helpful in growing applications like advanced driver assistance system (ADAS), where the number of sensors and processing time are increasing. Simulations results shown prove an effective reduction in transistor count, and a good performance of the system is demonstrated, as well.

Power and area-efficient register designs involving EHO algorithm

PurposeThis paper aims to design three low-power and area-efficient serial input parallel output (SIPO) register designs, namely, transistor count reduction technique shift register (TCRSR), series stacking in TCR shift register (S-TCRSR) and forced stacking of transistor in TCR shift register (FST in TCRSR). Shift registers (SR) are the basic building blocks of all types of digital applications. The performance of all the designs has been improved through one of the metaheuristic algorithms named elephant herding optimization (EHO) algorithm and hence suited for low-power very large scale integration (VLSI) applications. It is for the first time that the EHO algorithm is implemented in memory elements.Design/methodology/approachThe registers together with clock network consume 18-36 percentage of the total power consumption of a microprocessor. The proposed designs are implemented using low-power and high-performance double edge-triggered D flip-flops with least count of clocked transistors involving transmission gate. The second and third register designs are developed from the modified version of the first one employing series and forced stacking, thereby reducing static power because of sub-threshold leakage current. The performance parameters such as power-delay-product (PDP) and leakage power are further optimized using the EHO algorithm. A greater reduction in power is achieved in all the designs by utilizing the EHO algorithm.FindingsAll the designs are simulated at a supply voltage of 1 V/500 MHz when the input switching activity is 25 percentage in Cadence Virtuoso using 45 nm CMOS technology. Nine recently proposed SR designs are simulated in the same conditions, and the performance has been compared with the proposed ones. The simulated results prove the excellence of proposed designs in different performance parameters like leakage power, energy-delay-product (EDP), PDP, layout area compared with the recent designs. The PDPdq value has a reduction of 95.9per cent (TCRSR), 96.6per cent (S-TCRSR) and 97per cent (FST in TCRSR) with that of a conventional shift register (TGSR).Originality/valueThe performance of proposed low-power SR designs is enhanced using EHO algorithm. The optimized performance results have been compared with a few optimization algorithms. It is for the first time that EHO algorithm is implemented in memory elements.

Carbon Nanotube and Resistive Random Access Memory Based Unbalanced Ternary Logic Gates and Basic Arithmetic Circuits

In this paper, the design of ternary logic gates (standard ternary inverter, ternary NAND, ternary NOR) based on carbon nanotube field effect transistor (CNTFET) and resistive random access memory (RRAM) is proposed. Ternary logic has emerged as a very promising alternative to the existing binary logic systems owing to its energy efficiency, operating speed, information density and reduced circuit overheads such as interconnects and chip area. The proposed design employs active load RRAM and CNTFET instead of large resistors to implement ternary logic gates. The proposed ternary logic gates are then utilised to carry out basic arithmetic functions and is extendable to implement additional complex functions. The proposed ternary gates show significant advantages in terms of component count, chip area, power consumption, energy consumption and dense fabrication. The results demonstrate the advantage of the proposed models with a reduction of 50% in transistor count for the STI, TNAND and TNOR logic gates. For THA and THS arithmetic modules 65.11% reduction in transistor count is observed while for TM design, around 38% reduction is observed. In this work, we aim to demonstrate the viability of RRAM in the design of ternary logic systems, thus the focus is mainly on obtaining the proper functionality of the proposed design. Also the proposed logic gates show a very small variation in power consumption and energy consumption with variation in process parameters, temperature, output load, supply voltage and operating frequency. For simulations, HSPICE tool is used to verify the authenticity of the proposed designs. The ternary half adder, ternary half subtractor and ternary multiplier circuits are then implemented utilising the proposed gates and validated through simulations.

VLSI Implementation of Seed Transistor for Super Gate Design based on Grid based Transistor Network Generation

In VLSI digital design, the Propagation Delay, Power Dissipation and Area of circuits are strongly related to the number of transistors which are present on an IC. Hence transistor optimization is special interest when designing digital integrated circuits. Therefore, efficient algorithms are used to generate optimized transistor networks, which are quite useful for designing digital integrated circuits (ICs). Several methods have been proposed for generating and optimizing transistor networks. Most Traditional solutions are based on factoring Boolean expressions in which only Chain - Parallel (CP) arrangement of transistors can be obtained from factored forms. Whereas grid-based methods are able to find CP and also non - CP (NCP) arrangements with potential reduction of transistor count. This method is an effective way of improvising VLSI circuits. In this an efficient algorithm is proposed i.e. Novel (Seed) method. It is automatically generates networks with minimal transistor count starting with irredundant sum of products (ISOPs) as inputs. Novel method is able to deliver both CP switching networks and NCP switching network arrangements, which improves VLSI circuit’s performance in terms of area, power and delay. All the network circuits are implemented in ASIC Cadence by using 45nm and 90nm technology with GPDK libraries. By using Cadence Virtuoso tool, it can obtain schematics of design and its test bench, power analysis, SPICE simulation and its simulation waveform.

Design and Analysis of Power Efficient TG Based Dual Edge Triggered Flip-Flops with Stacking Technique

One of the paramount issues in the field of VLSI design is the rapid increase in power consumption. Therefore, it is necessary to develop power-efficient circuits. Here, three new simple architectures are presented for a Dynamic Double Edge Triggered Flip-flop named as Transistor Count Reduction Flip-flop, S-TCRFF (Series Stacking in TCRFF) and FST in TCRFF (Forced Stacking of Transistor in TCRFF). The first one features a dynamic design comprising of transmission gate in which total transistor count has greatly reduced without affecting the logic, thereby attaining better power and speed performance. For the reduction of static power, two types of stacking called series and forced transistor stacking are applied. The circuits are simulated using Cadence Virtuoso in 45[Formula: see text]nm CMOS technology with a power supply of 1[Formula: see text]V at 500[Formula: see text]MHz when input switching activity is 25%. The simulated results indicated that the new designs (TCRFF, S-TCRFF and FST in TCRFF) excelled in different circuit performance indices like Power-Delay-Product (PDP), Energy-Delay-Product (EDP), average and leakage power with less layout area compared with the performance of nine recently proposed FF designs. The improvement in PDPdq value was up to 89.2% (TCRFF), 89.9% (S-TCRFF) and 90.3% (FST in TCRFF) with conventional transmission gate FF (TGFF).

A Novel Very Low-Complexity Multi-valued Logic Comparator in Nanoelectronics

Using multi-valued logic (MVL) can reduce chip connections, which can have a direct effect on the chip area and connections power consumption. In the recent years, due to the high capability of nanotechnology in designing MVLs, some researchers have focused on this field. In designing MVL circuits, the low-complexity design is of great importance to fulfill the MVL aim. In this paper, a very low-complexity comparator for the MVL is proposed based on the multi-threshold voltage in CNTFETs. The proposed comparator in the 1-bit greater function only needs four transistors for all multi-valued logics; this results in a considerable transistor count reduction in comparison with the pervious works relying on 32 and 50 transistors in a ternary to quaternary case, respectively. Also, the number of 1-bit comparators is reduced from 50 and 74 transistors for the ternary to quaternary cases in the previous works to 12 in the proposed design. Additionally, the multi-digit comparator using the novel digit comparator is proposed. The simulation results using the Stanford 32 nm CNTFET library in HSPICE confirm the proper operation of the proposed comparator with the same range in PDP, in comparison with the previous works.

Transistor Count Reduction by Gate Merging

A large set of ASICs uses much more transistors than its necessity, as they use a library of cells with a limited amount of logic functions. This small number of logic functions in a traditional cell library represents an inherent limitation in the optimization of the number of transistors. In modern technologies, static power consumption is related to the number of transistors. To reduce leakage power, it is necessary to optimize the number of transistors. Therefore, it demands the use of a library-free physical design approach, using tools to allow the automatic layout synthesis of any transistor network. The goal of this paper is to present a new method to optimize the logical netlist, willing to reduce the number of transistors and connections, as well as the number of vias. Post-processing of the original logic netlist generated in a traditional design flow is completed, and a set of basic cells is replaced by just one new equivalent logic gate, thus simultaneously reducing the number of transistors. The connected cells of unitary fanout are considered to be merged into a new complex gate (usually not available in a traditional cell library). This approach is capable to reduce the number of transistors of a circuit by 21% on average when compared to the traditional solution, and by 4% when compared to other logic minimization tools. This provides an important leakage power reduction.

A novel nanoscaled Schottky barrier based transmission gate and its digital circuit applications

In this work we propose and simulate a compact nanoscaled transmission gate (TG) employing a single Schottky barrier based transistor in the transmission path and a single transistor based Sajad-Sunil-Schottky (SSS) device as an inverter. Therefore, just two transistors are employed to realize a complete transmission gate which normally consumes four transistors in the conventional technology. The transistors used to realize the transmission path and the SSS inverter in the proposed TG are the double gate Schottky barrier devices, employing stacks of two metal silicides, platinum silicide (PtSi) and erbium silicide (ErSi). It has been observed that the realization of the TG gate by the proposed technology has resulted into a compact structure, with reduced component count, junctions, interconnections and regions in comparison to the conventional technology. The further focus of this work is on the application part of the proposed technology. So for the first time, the proposed technology has been used to realize various combinational circuits, like a two input AND gate, a 2:1 multiplexer and a two input XOR circuits. It has been observed that the transistor count has got reduced by half in a TG, two input AND gate, 2:1 multiplexer and in a two input XOR gate. Therefore, a significant reduction in transistor count and area requirement can be achieved by using the proposed technology. The proposed technology can be also used to perform the compact realization of other combinational and sequential circuitry in future.

Operation regimes and electrical transport of steep slope Schottky Si-FinFETs

In the quest for energy efficient circuits, considerable focus has been given to steep slope and polarity-controllable devices, targeting low supply voltages and reduction of transistor count. The recently proposed concept of the three-independent gated Si-FinFETs with Schottky-barriers (SBs) has proven to bring both functionalities even in a single device. However, the complex combination of transport properties including Schottky emission and weak impact ionization as well as the body effect makes the design of such devices challenging. In this work, we perform a deep electrical characterization analysis to visualize and decouple the different operation regimes and electrical properties of the SB Si-FinFETs using a graphical transport map. From these, we give important guidelines for the design of future devices.

GDI logic implementation of uniform sized CSLA architectures in 45 nm SOI technology

The Carry Select Adder (CSLA) is one of the fastest multi-bit adder architectures being used in various high speed processors. The CSLA is fast but compromises on the area and power consumption due to its complex architecture when implemented using standard CMOS logic. In this work, an alternate implementation of the CSLA architecture is done using Gate Diffusion Input (GDI) logic; instead of the CMOS logic. This approach simplifies the overall architectural dimensions due to reduction in transistor count as well as the power consumption. In this work, various types of CSLA architectures are implemented using the GDI logic and compared with their CMOS logic counterparts in terms of average power, delay and transistor count in 45nm technology node. The comparative analysis clearly shows that GDI based circuits are better compared to CMOS logic implementations.

Novel Multiplexer Design Using Multi-State Spatial Wavefunction-Switched (SWS) FETs

In this paper, we propose a multiplexer design based on use of a twin channel and twin drain spatial wavefunction-switched field-effect transistors (SWSFETs). SWSFET comprises of vertically stacked coupled quantum wells devices, which are the channels, where depending on the gate voltage only one of the channels is in conduction mode. Using SWSFET in multi-channel and single drain configuration operates as a multi-valued logic device. 2:1 and 4:2 multiplexer designs are proposed which are compatible with current CMOS technology and with all SWSFET. Both designs lead to greater than 4X reduction in transistor count. Ngspice simulation of circuits is also presented.