A Novel Ultra Low-Power 10T CNFET-Based Full Adder Cell Design in 32nm Technology

Nowadays, energy consumption is the main concern in portable electronic systems such as laptops, smart mobile phones, personal digital assistances (PDAs) and so forth. Considering that the 1-bit Full adder cell has been the determinant circuit due to its wide usage in these systems, it affects the entire performance of the electronic system. In this paper, a novel low-power and low-energy 10 transistor (10T) Full Adder cell using NAND/NOR functions based on carbon nanotube field effect transistors (CNFETs) is presented. The proposed cell showed superiority in terms of power-delay product (PDP) compared to the other cells under different simulation condition, such as power supply, temperature, load and operating frequency variations. Moreover, a Monte Carlo (MC) simulation was conducted to study the reliability of the proposed cell against manufacturing process variations (i.e. the variations of diameters of carbon nanotubes). Simulations confirmed the robustness of the proposed cell

Energy Efficient CNTFET Based Full Adder Using Hybrid Logic

Full Adder is the basic element for arithmetic operations used in Very Large Scale Integrated (VLSI) circuits, therefore, optimization of 1-bit full adder cell improves the overall performance of electronic devices. Due to unique mechanical and electrical characteristics, carbon nanotube field effect transistors (CNTFET) are found to be the most suitable alternative for metal oxide field effect transistor (MOSFET). CNTFET transistor utilizes carbon nanotube (CNT) in the channel region. In this paper, high speed, low power and reduced transistor count full adder cell using CNTFET 32nm technology is presented. Two input full swing XOR gate is designed using 4 transistors which is further used to generate Sum and Carry output signals with the help of Gate-Diffusion-Input (GDI) Technique thus reducing the number of transistors involved. Proposed design simulated in Cadence Virtuoso with 32nm CNTFET technology and results is better design as compared to existing circuits in terms of Power, Delay, Power-Delay-Product (PDP), Energy Consumption and Energy-Delay-Product (EDP)

Building Efficient and Reliable Emerging Technology Systems

The semiconductor industry has been reaping the benefits of Moore’s law powered by Dennard’s voltage scaling for the past fifty years. However, with the end of Dennard scaling, silicon chip manufacturers are facing a widespread plateau in performance improvements. While the architecture community has focused its effort on exploring parallelism, such as with multi-core, many-core and accelerator-based systems, chip manufacturers have been forced to explore beyond-Moore technologies to improve performance while maintaining power density. Examples of such technologies include monolithic 3D integration, carbon nanotube transistors, tunneling-based transistors, spintronics and quantum computing. However, the infancy of the manufacturing process of these new technologies impedes their usage in commercial products. The goal of this dissertation is to combine both architectural and device-level efforts to provide solutions across the computing stack that can overcome the reliability concerns of emerging technologies. This allows for beyond-Moore systems to compete with highly optimized silicon-based processors, thus, enabling faster commercialization of such systems. This dissertation proposes the following key steps: (i) Multifaceted understanding and modeling of variation and yield issues that occur in emerging technologies, such as carbon nanotube transistors (CNFETs). (ii) Design of systems using suitable logic families such as pass transistor logic that provide high performance. (iii) Design of a multi-granular fault-tolerant reconfigurable architecture that enhances yield and performance. (iv) Design of a multi-technology, multi-accelerator heterogeneous system (v) Development of real-time constrained efficient workload scheduling mechanism for heterogeneous systems. This dissertation first presents the use of pass transistor logic family as an alternate to the CMOS logic family for CNFETs to improve performance. It explores various architectural design choices for CNFETs using pass transistor logic (PTL) to create an energy-efficient RISC-V processor. Our results show that while a CNFET RISC-V processor using CMOS logic achieves a 2.9x energy-delay product (EDP) improvement over a silicon design, using PTL along the critical path components of the processor can boost EDP improvement by 5x as well as reduce area by 17% over 16 nm silicon CMOS. This document further builds on providing fault-tolerant and yield enhancing solutions for emerging 3D integration compatible technologies in the context of CNFETs. The proposed framework can efficiently support high-variation technologies by providing protection against manufacturing defects at multiple granularities: module and pipeline-stage levels. Based on the variation observed in a synthesized design, a reliable CNFET-based 3D multi-granular reconfigurable architecture, 3DTUBE, is presented to overcome the manufacturing difficulties. For 0.4-0.7 V, 3DTUBE provides up to 6.0x higher throughput and 3.1x lower EDP compared to a silicon-based multi-core design evaluated at 1 part per billion transistor failure rate, which is 10,000x lower in comparison to CNFET’s failure rate. This dissertation then ventures into building multi-accelerator heterogeneous systems and real-time schedulers that cater to the requirements of the applications while taking advantage of the underlying heterogeneous system. We introduce optimizations like task pruning, hierarchical hetero-ranking and rank update built upon two scheduler policies (MS-static and MS-dynamic), that result in a performance improvement of 3.5x (average) for real-world autonomous vehicle applications, when compared against state-of-the-art schedulers. Adopting insights from the above work, this thesis presents a multi-accelerator, multi-technology heterogeneous system powered by a multi-constrained scheduler that optimizes for varying task requirements to achieve up to 6.1x better energy over a baseline silicon-based system.PHDElectrical and Computer EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169699/1/aporvaa_1.pd

CNTFET-Based Design of a High-Efficient Full Adder Using XOR Logic

This paper presents a new low power and high speed full adder based on Carbon Nano Tube Field Effect Transistor (CNTFET) technology. This proposed full adder is based on a XOR logic function using 32 nm CNTFET technology. The MOSFET-like CNTFET is applied in this paper to use CMOS (Complementary Metal Oxide Semiconductor) logic gate. The better structure of CNTFET transistors can improve the performance of full adder based on CNTFET technology [1]. The proposed full adder is simulated in different frequencies, various supply voltages, temperatures and load capacitances to prove better performance in different conditions using the Synopsys HSPICE simulator software in comparison with previous full adders in CNTFET technology

CNTFET-Based Design of a High-Efficient Full Adder Using XOR Logic

This paper presents a new low power and high speed full adder based on Carbon Nano Tube Field Effect Transistor (CNTFET) technology. This proposed full adder is based on a XOR logic function using 32 nm CNTFET technology. The MOSFET-like CNTFET is applied in this paper to use CMOS (Complementary Metal Oxide Semiconductor) logic gate. The better structure of CNTFET transistors can improve the performance of full adder based on CNTFET technology [1]. The proposed full adder is simulated in different frequencies, various supply voltages, temperatures and load capacitances to prove better performance in different conditions using the Synopsys HSPICE simulator software in comparison with previous full adders in CNTFET technology

Novel Ternary Logic Gates Design in Nanoelectronics

In this paper, standard ternary logic gates are initially designed to considerably reduce static power consumption. This study proposes novel ternary gates based on two supply voltages in which the direct current is eliminated and the leakage current is reduced considerably. In addition, ST-OR and ST-AND are generated directly instead of ST-NAND and ST-NOR. The proposed gates have a high noise margin near V_(DD)/4. The simulation results indicated that the power consumption and PDP underwent a~sharp decrease and noise margin showed a considerable increase in comparison to both one supply and two supply based designs in previous works. PDP is improved in the proposed OR, as compared to one supply and two supply based previous works about 83% and 63%, respectively. Also, a memory cell is designed using the proposed STI logic gate, which has a considerably lower static power to store logic ‘1’ and the static noise margin, as compared to other designs

Variability and reliability analysis of carbon nanotube technology in the presence of manufacturing imperfections

In 1925, Lilienfeld patented the basic principle of field effect transistor (FET). Thirty-four years later, Kahng and Atalla invented the MOSFET. Since that time, it has become the most widely used type of transistor in Integrated Circuits (ICs) and then the most important device in the electronics industry. Progress in the field for at least the last 40 years has followed an exponential behavior in accordance with Moore¿s Law. That is, in order to achieve higher densities and performance at lower power consumption, MOS devices have been scaled down. But this aggressive scaling down of the physical dimensions of MOSFETs has required the introduction of a wide variety of innovative factors to ensure that they could still be properly manufactured. Transistors have expe- rienced an amazing journey in the last 10 years starting with strained channel CMOS transistors at 90nm, carrying on the introduction of the high-k/metal-gate silicon CMOS transistors at 45nm until the use of the multiple-gate transistor architectures at 22nm and at recently achieved 14nm technology node. But, what technology will be able to produce sub-10nm transistors? Different novel materials and devices are being investigated. As an extension and enhancement to current MOSFETs some promising devices are n-type III-V and p-type Germanium FETs, Nanowire and Tunnel FETs, Graphene FETs and Carbon Nanotube FETs. Also, non-conventional FETs and other charge-based information carrier devices and alternative information processing devices are being studied. This thesis is focused on carbon nanotube technology as a possible option for sub-10nm transistors. In recent years, carbon nanotubes (CNTs) have been attracting considerable attention in the field of nanotechnology. They are considered to be a promising substitute for silicon channel because of their small size, unusual geometry (1D structure), and extraordinary electronic properties, including excellent carrier mobility and quasi-ballistic transport. In the same way, carbon nanotube field-effect transistors (CNFETs) could be potential substitutes for MOSFETs. Ideal CNFETs (meaning all CNTs in the transistor behave as semiconductors, have the same diameter and doping level, and are aligned and well-positioned) are predicted to be 5x faster than silicon CMOS, while consuming the same power. However, nowadays CNFETs are also affected by manufacturing variability, and several significant challenges must be overcome before these benefits can be achieved. Certain CNFET manufacturing imperfections, such as CNT diameter and doping variations, mispositioned and misaligned CNTs, high metal-CNT contact resistance, the presence of metallic CNTs (m-CNTs), and CNT density variations, can affect CNFET performance and reliability and must be addressed. The main objective of this thesis is to analyze the impact of the current CNFET manufacturing challenges on multi-channel CNFET performance from the point of view of variability and reliability and at different levels, device and circuit level. Assuming that CNFETs are not ideal or non-homogeneous because of today CNFET manufacturing imperfections, we propose a methodology of analysis that based on a CNFET ideal compact model is able to simulate heterogeneous or non-ideal CNFETs; that is, transistors with different number of tubes that have different diameters, are not uniformly spaced, have different source/drain doping levels, and, most importantly, are made up not only of semiconducting CNTs but also metallic ones. This method will allow us to analyze how CNT-specific variations affect CNFET device characteristics and parameters and CNFET digital circuit performance. Furthermore, we also derive a CNFET failure model and propose an alternative technique based on fault-tolerant architectures to deal with the presence of m-CNTs, one of the main causes of failure in CNFET circuits

Optimization of CNFET Parameters for High Performance Digital Circuits

The Carbon Nanotube Field Effect Transistor (CNFET) is one of the most promising candidates to become successor of silicon CMOS in the near future because of its better electrostatics and higher mobility. The CNFET has many parameters such as operating voltage, number of tubes, pitch, nanotube diameter, dielectric constant, and contact materials which determine the digital circuit performance. This paper presents a study that investigates the effect of different CNFET parameters on performance and proposes a new CNFET design methodology to optimize performance characteristics such as current driving capability, delay, power consumption, and area for digital circuits. We investigate and conceptually explain the performance measures at 32 nm technologies for pure-CNFET, hybrid MOS-CNFET, and CMOS configurations. In our proposed design methodology, the power delay product (PDP) of the optimized CNFET is about 68%, 63%, and 79% less than that of the nonoptimized CNFET, hybrid MOS-CNFET, and CMOS circuits, respectively. Therefore, the proposed CNFET design is a strong candidate to implement high performance digital circuits