Beyond CMOS technologies aim to overcome limitations of traditional CMOS devices. Evolutionary approaches include Silicon on Insulator (SOI), dual gate FETs, and SiGe structures. SOI provides electrical isolation and radiation hardness. Dual gate FETs reduce short channel effects. Carbon nanotubes and biomolecular/tactile computing are also discussed as potential future technologies, with biomolecular computing utilizing biological recognition through molecular shapes. Tactile computing relies on physical interactions rather than symbolic processing.
This document discusses two main techniques for isolating transistors in semiconductor fabrication: LOCOS (Local Oxidation of Silicon) and STI (Shallow Trench Isolation). LOCOS uses a thermal oxidation process which results in a "bird's beak" encroachment that wastes surface area. STI improves on LOCOS by etching shallow trenches and filling them with deposited oxide, avoiding the bird's beak effect but requiring more processing steps. Both techniques utilize thermally grown oxides and masks like silicon nitride to selectively grow isolation oxides and define active device areas.
This document provides an overview of an "Analog VLSI Design" course. The goals of the course are to introduce principles of analog integrated circuit design and CMOS technology. Students will learn about CMOS layout design using CAD tools and complete a design project. The course covers topics including CMOS technology, resistors, capacitors, MOSFETs, current mirrors, amplifiers, and data converters. Assessment includes homework, a project, and a final exam.
The document discusses CMOS technology which uses both NMOS and PMOS transistors in a complementary way. It has low power dissipation as power is only consumed during switching. CMOS circuits like inverters, NAND and NOR gates are constructed using a pull-up network of PMOS transistors and a pull-down network of NMOS transistors. The fabrication of CMOS transistors involves depositing and patterning materials on a silicon wafer through lithography. CMOS has advantages like low power, high noise immunity and is widely used in applications like computers, processors and memory chips.
This document provides an overview of the course EC8095-VLSI Design. It describes 5 units that will be covered: 1) Introduction to MOS transistors, 2) Combinational MOS logic circuits, 3) Sequential circuit design, 4) Design of arithmetic building blocks and subsystems, and 5) Implementation strategies. The first unit introduces MOS transistor structure and CMOS technology. The second unit discusses combinational logic circuits and design considerations. The third unit covers sequential circuit specification and design. The fourth unit deals with arithmetic units and memory. The fifth and final unit describes IC technologies including ASICs, gate arrays, and full custom ICs.
The CMOS fabrication process in VLSI.
CMOS (complementary metal-oxide-semiconductor) is the term usually used to describe the small amount of memory on a computer motherboard that stores the BIOS settings.
Micro-electromechanical systems (MEMS) are miniature systems that combine electrical and mechanical components. RF MEMS are MEMS devices that operate at radio frequencies and are used in applications like switches, inductors, capacitors, antennas, resonators, and filters. Some key challenges for RF MEMS include relatively low switching speeds, limited lifetime reliability, sensitivity to temperature changes, humidity effects, and vibrations/shocks during operation. Overcoming challenges in areas like packaging, modeling reliability, and further integration will be important for wider commercialization of RF MEMS technologies.
This document discusses two main techniques for isolating transistors in semiconductor fabrication: LOCOS (Local Oxidation of Silicon) and STI (Shallow Trench Isolation). LOCOS uses a thermal oxidation process which results in a "bird's beak" encroachment that wastes surface area. STI improves on LOCOS by etching shallow trenches and filling them with deposited oxide, avoiding the bird's beak effect but requiring more processing steps. Both techniques utilize thermally grown oxides and masks like silicon nitride to selectively grow isolation oxides and define active device areas.
This document provides an overview of an "Analog VLSI Design" course. The goals of the course are to introduce principles of analog integrated circuit design and CMOS technology. Students will learn about CMOS layout design using CAD tools and complete a design project. The course covers topics including CMOS technology, resistors, capacitors, MOSFETs, current mirrors, amplifiers, and data converters. Assessment includes homework, a project, and a final exam.
The document discusses CMOS technology which uses both NMOS and PMOS transistors in a complementary way. It has low power dissipation as power is only consumed during switching. CMOS circuits like inverters, NAND and NOR gates are constructed using a pull-up network of PMOS transistors and a pull-down network of NMOS transistors. The fabrication of CMOS transistors involves depositing and patterning materials on a silicon wafer through lithography. CMOS has advantages like low power, high noise immunity and is widely used in applications like computers, processors and memory chips.
This document provides an overview of the course EC8095-VLSI Design. It describes 5 units that will be covered: 1) Introduction to MOS transistors, 2) Combinational MOS logic circuits, 3) Sequential circuit design, 4) Design of arithmetic building blocks and subsystems, and 5) Implementation strategies. The first unit introduces MOS transistor structure and CMOS technology. The second unit discusses combinational logic circuits and design considerations. The third unit covers sequential circuit specification and design. The fourth unit deals with arithmetic units and memory. The fifth and final unit describes IC technologies including ASICs, gate arrays, and full custom ICs.
The CMOS fabrication process in VLSI.
CMOS (complementary metal-oxide-semiconductor) is the term usually used to describe the small amount of memory on a computer motherboard that stores the BIOS settings.
Micro-electromechanical systems (MEMS) are miniature systems that combine electrical and mechanical components. RF MEMS are MEMS devices that operate at radio frequencies and are used in applications like switches, inductors, capacitors, antennas, resonators, and filters. Some key challenges for RF MEMS include relatively low switching speeds, limited lifetime reliability, sensitivity to temperature changes, humidity effects, and vibrations/shocks during operation. Overcoming challenges in areas like packaging, modeling reliability, and further integration will be important for wider commercialization of RF MEMS technologies.
The document discusses energy band diagrams and MOS structures. It covers topics like depletion and inversion modes, current-voltage characteristics of MOSFETs, channel geometry, pinch-off, and length modulation. Small-signal equivalent circuit models of JFETs and MOSFETs are presented at different frequencies. Different types of MOSFETs are described, including dual-gate, FinFET, and double-gate structures.
The document discusses layout challenges at the 90nm technology node. It covers analog layout challenges including shallow trench isolation (STI) stress and well proximity effects that can degrade transistor performance. For RF layout, it discusses the importance of minimizing interconnect and device parasitics. Interconnect parasitics like resistance and capacitance can be reduced by shorter lengths, wider widths, and using higher metal layers. Device parasitics are also discussed and how optimizing the drain area of differential pairs by folding can help minimize parasitic capacitance effects.
The document provides an overview of the history and evolution of semiconductors and integrated circuits from 1947 to present. It discusses key inventions and milestones such as the transistor in 1947, the integrated circuit in 1961, and Moore's Law predicting transistor doubling every two years. It also covers different chip design approaches including full custom, standard cell, gate arrays, and FPGAs, along with their relative costs, performance, and design complexities.
This document describes the key process steps in a standard CMOS fabrication process flow. It begins with an overview of basic CMOS circuits and substrate preparation. Then each major step is outlined, including well formation through ion implantation, gate oxide growth, polysilicon deposition and patterning, source/drain implantation and annealing. Additional metal layers are deposited and patterned before passivation completes the CMOS structure. The process requires 16 photomasks and over 100 individual process steps to fabricate modern integrated circuits using complementary NMOS and PMOS transistors.
This document provides an overview of metallization for integrated circuits. It discusses the requirements and purposes of metallization, including interconnecting thousands of devices on chips. Two common metallization methods described are vacuum evaporation and sputter deposition. Vacuum evaporation locally heats a material source to vaporize and deposit the metal film, while sputter deposition uses ion momentum from a plasma to eject atoms from a target onto the substrate. The document outlines the apparatus and processes for each technique.
Optical networks use fiber optic technologies and components to transmit data at high speeds. They employ network architectures like synchronous optical networks (SONET) and passive optical networks (PONs) to route data through the core transport network and provide access to customers. SONET uses time-division multiplexing and self-healing ring topologies to interconnect equipment from different vendors. PONs have a star topology and use different wavelengths to transmit data downstream and upstream without electronic regeneration between transmitters and receivers.
The document provides an overview of the history and scaling of transistors and integrated circuits. It discusses how vacuum tubes were replaced by transistors, with the first transistor invented in 1947 and the first integrated circuit in 1958. It describes how continuous scaling and improvements in silicon manufacturing have led to billions of transistors being integrated onto a single chip today. The document then discusses different transistor technologies, including MOSFETs, and how scaling to smaller sizes introduced challenges like short channel effects that new transistor designs like FinFETs help address.
This presentation has given a brief introduction and working of CMOS Logic Structures which includes MOS logic, CMOS logic, CMOS logic structure, CMOS complementary logic, pass transistor logic, bi CMOS logic, pseudo –nMOS logic, CMOS domino logic, Cascode Voltage Switch Logic(CVSL), clocked CMOS logic(c²mos), dynamic CMOS logic
Have an overview of the most conventionally utilized crystal growth techniques: process, diagrams, advantages, and disadvantages. This is the presentation of my "PV cells and materials" course at the MSc Engg. level.
The document discusses various techniques for electrically isolating devices in integrated circuits. It describes junction isolation, which uses reverse biased PN junctions, but this did not scale well as devices became smaller. Dielectric isolation techniques like LOCOS and STI were developed using deposited or thermally grown oxides. LOCOS had limitations like bird's beak encroachment affecting small device areas. STI involves etching trenches and depositing oxide to fill them, avoiding issues with LOCOS at small scales.
5G technology enables three key services:
1) Enhanced mobile broadband provides high data transmission rates for streaming high-resolution video, augmented reality, and online gaming.
2) Ultra-reliable low latency communications meets exacting requirements for latency and reliability needed for applications like autonomous vehicles.
3) Massive machine-type communications supports connectivity for a very large number of devices that intermittently transmit small amounts of data, enabling growth in IoT.
1. Fully Depleted Silicon On Insulator (FD-SOI) is an innovation that uses an ultra-thin silicon film and buried oxide layer to improve transistor performance and reduce leakage currents.
2. By using a thin buried oxide and silicon film, FD-SOI allows the depletion region to cover the entire film, improving electrostatic characteristics and reducing parasitic capacitance compared to bulk transistors.
3. The improvements allow FD-SOI transistors to operate faster at lower voltages while significantly reducing leakage currents and improving power efficiency through improved body biasing controls.
A simple N-channel MOSFET can be used as a diode, Switch and Active resistor. This presentation is a part of course of Analog CMOS Design, based on textbook of same title by Allen Holberg.
This presentation discusses the basics about how to realize logic functions using Static CMOS logic. This presentation discusses about how to realize a Boolean expression by drawing a Pull-up network and a pull-down network. It also briefs about the pass transistor logic and the concepts of weak and strong outputs.
This document discusses junctionless transistors as an alternative to traditional transistors. Junctionless transistors have no p-n junctions and instead use uniformly doped semiconductor material. They offer advantages like simpler fabrication without implantation or annealing steps, reduced short channel effects, higher carrier mobility, and lower leakage current. However, they can have greater threshold voltage variability than conventional transistors. The document provides details on the structure and operation of junctionless transistors, comparing them to traditional transistors and discussing their potential to enable further device miniaturization.
At a time when the end of Moore's Law is imminent, the quest for a suitable alternative finds a possible destination at Spintronicsl trlying on the spin of an electron instead of its charge. Magnetoresistive RAM uses electron spin and associated magnetic moment for memory purposes.
MRAM promises to be the Holy Grail of the memory world, promising features like amazingly high endurance, low power, non volatility, reduced read and write times, among many others.
This document discusses MOSFET fabrication and thin-film formation processes. It describes the basic MOSFET fabrication steps including oxidation, diffusion, etching, and metallization. It also discusses NMOS and CMOS development processes. For thin-film formation, it describes the fabrication of planar resistors, inductors, and capacitors using thin-film deposition and patterning. Resistors are formed from resistive thin films, inductors use planar spiral patterns, and capacitors use metal-oxide-metal or interdigitated finger structures. Formulas for calculating resistance, inductance, and capacitance values are also provided.
Faults can occur in digital circuits due to processing errors, material defects, time-dependent failures, or packaging issues. A fault is a physical defect, an error is the manifestation of a fault causing incorrect outputs, and a failure occurs when a circuit deviates from its specified behavior due to an error. The single stuck-at fault model assumes a line is permanently stuck at 0 or 1, and is commonly used due to its simplicity and ability to model many defects. Bridging faults occur when two lines are accidentally connected, and can be modeled as ANDing or ORing the signals. Feedback bridging can cause circuits to oscillate or behave asynchronously under certain input conditions.
1) The document discusses SOI-CMOS device technology, which uses a silicon-on-insulator structure to create transistors on a thin silicon film layer separated from the substrate by an insulating layer. This structure offers advantages like lower power consumption and higher speeds.
2) It summarizes the development of a 0.2 micrometer SOI-CMOS process at Oki, including a 50nm thin silicon film layer and cobalt silicide to reduce resistance. Tests showed improved speed and lower voltage operation compared to bulk CMOS.
3) Potential applications discussed include low power digital devices, radio frequency circuits where reduced capacitance enables better high-frequency performance, and mixed-signal chips where substrate isolation reduces interference.
This document discusses ultra thin body SOI FETs. Some key points:
- SOI uses a thin silicon layer on an insulating substrate to reduce parasitic capacitance and improve performance over bulk silicon. Fully depleted SOI is preferred for its thin size and reduced leakage/power consumption.
- Benefits of SOI include lower capacitance, resistance to latch-up, higher performance at lower voltages, reduced temperature effects, better yields, and reduced leakage currents.
- Ultra thin body SOI FETs have even better gate control and mobility due to thin channel thickness, lower parasitic capacitance, and reduced leakage currents, making them useful for applications like memory, microelectronics, RF devices,
The document discusses energy band diagrams and MOS structures. It covers topics like depletion and inversion modes, current-voltage characteristics of MOSFETs, channel geometry, pinch-off, and length modulation. Small-signal equivalent circuit models of JFETs and MOSFETs are presented at different frequencies. Different types of MOSFETs are described, including dual-gate, FinFET, and double-gate structures.
The document discusses layout challenges at the 90nm technology node. It covers analog layout challenges including shallow trench isolation (STI) stress and well proximity effects that can degrade transistor performance. For RF layout, it discusses the importance of minimizing interconnect and device parasitics. Interconnect parasitics like resistance and capacitance can be reduced by shorter lengths, wider widths, and using higher metal layers. Device parasitics are also discussed and how optimizing the drain area of differential pairs by folding can help minimize parasitic capacitance effects.
The document provides an overview of the history and evolution of semiconductors and integrated circuits from 1947 to present. It discusses key inventions and milestones such as the transistor in 1947, the integrated circuit in 1961, and Moore's Law predicting transistor doubling every two years. It also covers different chip design approaches including full custom, standard cell, gate arrays, and FPGAs, along with their relative costs, performance, and design complexities.
This document describes the key process steps in a standard CMOS fabrication process flow. It begins with an overview of basic CMOS circuits and substrate preparation. Then each major step is outlined, including well formation through ion implantation, gate oxide growth, polysilicon deposition and patterning, source/drain implantation and annealing. Additional metal layers are deposited and patterned before passivation completes the CMOS structure. The process requires 16 photomasks and over 100 individual process steps to fabricate modern integrated circuits using complementary NMOS and PMOS transistors.
This document provides an overview of metallization for integrated circuits. It discusses the requirements and purposes of metallization, including interconnecting thousands of devices on chips. Two common metallization methods described are vacuum evaporation and sputter deposition. Vacuum evaporation locally heats a material source to vaporize and deposit the metal film, while sputter deposition uses ion momentum from a plasma to eject atoms from a target onto the substrate. The document outlines the apparatus and processes for each technique.
Optical networks use fiber optic technologies and components to transmit data at high speeds. They employ network architectures like synchronous optical networks (SONET) and passive optical networks (PONs) to route data through the core transport network and provide access to customers. SONET uses time-division multiplexing and self-healing ring topologies to interconnect equipment from different vendors. PONs have a star topology and use different wavelengths to transmit data downstream and upstream without electronic regeneration between transmitters and receivers.
The document provides an overview of the history and scaling of transistors and integrated circuits. It discusses how vacuum tubes were replaced by transistors, with the first transistor invented in 1947 and the first integrated circuit in 1958. It describes how continuous scaling and improvements in silicon manufacturing have led to billions of transistors being integrated onto a single chip today. The document then discusses different transistor technologies, including MOSFETs, and how scaling to smaller sizes introduced challenges like short channel effects that new transistor designs like FinFETs help address.
This presentation has given a brief introduction and working of CMOS Logic Structures which includes MOS logic, CMOS logic, CMOS logic structure, CMOS complementary logic, pass transistor logic, bi CMOS logic, pseudo –nMOS logic, CMOS domino logic, Cascode Voltage Switch Logic(CVSL), clocked CMOS logic(c²mos), dynamic CMOS logic
Have an overview of the most conventionally utilized crystal growth techniques: process, diagrams, advantages, and disadvantages. This is the presentation of my "PV cells and materials" course at the MSc Engg. level.
The document discusses various techniques for electrically isolating devices in integrated circuits. It describes junction isolation, which uses reverse biased PN junctions, but this did not scale well as devices became smaller. Dielectric isolation techniques like LOCOS and STI were developed using deposited or thermally grown oxides. LOCOS had limitations like bird's beak encroachment affecting small device areas. STI involves etching trenches and depositing oxide to fill them, avoiding issues with LOCOS at small scales.
5G technology enables three key services:
1) Enhanced mobile broadband provides high data transmission rates for streaming high-resolution video, augmented reality, and online gaming.
2) Ultra-reliable low latency communications meets exacting requirements for latency and reliability needed for applications like autonomous vehicles.
3) Massive machine-type communications supports connectivity for a very large number of devices that intermittently transmit small amounts of data, enabling growth in IoT.
1. Fully Depleted Silicon On Insulator (FD-SOI) is an innovation that uses an ultra-thin silicon film and buried oxide layer to improve transistor performance and reduce leakage currents.
2. By using a thin buried oxide and silicon film, FD-SOI allows the depletion region to cover the entire film, improving electrostatic characteristics and reducing parasitic capacitance compared to bulk transistors.
3. The improvements allow FD-SOI transistors to operate faster at lower voltages while significantly reducing leakage currents and improving power efficiency through improved body biasing controls.
A simple N-channel MOSFET can be used as a diode, Switch and Active resistor. This presentation is a part of course of Analog CMOS Design, based on textbook of same title by Allen Holberg.
This presentation discusses the basics about how to realize logic functions using Static CMOS logic. This presentation discusses about how to realize a Boolean expression by drawing a Pull-up network and a pull-down network. It also briefs about the pass transistor logic and the concepts of weak and strong outputs.
This document discusses junctionless transistors as an alternative to traditional transistors. Junctionless transistors have no p-n junctions and instead use uniformly doped semiconductor material. They offer advantages like simpler fabrication without implantation or annealing steps, reduced short channel effects, higher carrier mobility, and lower leakage current. However, they can have greater threshold voltage variability than conventional transistors. The document provides details on the structure and operation of junctionless transistors, comparing them to traditional transistors and discussing their potential to enable further device miniaturization.
At a time when the end of Moore's Law is imminent, the quest for a suitable alternative finds a possible destination at Spintronicsl trlying on the spin of an electron instead of its charge. Magnetoresistive RAM uses electron spin and associated magnetic moment for memory purposes.
MRAM promises to be the Holy Grail of the memory world, promising features like amazingly high endurance, low power, non volatility, reduced read and write times, among many others.
This document discusses MOSFET fabrication and thin-film formation processes. It describes the basic MOSFET fabrication steps including oxidation, diffusion, etching, and metallization. It also discusses NMOS and CMOS development processes. For thin-film formation, it describes the fabrication of planar resistors, inductors, and capacitors using thin-film deposition and patterning. Resistors are formed from resistive thin films, inductors use planar spiral patterns, and capacitors use metal-oxide-metal or interdigitated finger structures. Formulas for calculating resistance, inductance, and capacitance values are also provided.
Faults can occur in digital circuits due to processing errors, material defects, time-dependent failures, or packaging issues. A fault is a physical defect, an error is the manifestation of a fault causing incorrect outputs, and a failure occurs when a circuit deviates from its specified behavior due to an error. The single stuck-at fault model assumes a line is permanently stuck at 0 or 1, and is commonly used due to its simplicity and ability to model many defects. Bridging faults occur when two lines are accidentally connected, and can be modeled as ANDing or ORing the signals. Feedback bridging can cause circuits to oscillate or behave asynchronously under certain input conditions.
1) The document discusses SOI-CMOS device technology, which uses a silicon-on-insulator structure to create transistors on a thin silicon film layer separated from the substrate by an insulating layer. This structure offers advantages like lower power consumption and higher speeds.
2) It summarizes the development of a 0.2 micrometer SOI-CMOS process at Oki, including a 50nm thin silicon film layer and cobalt silicide to reduce resistance. Tests showed improved speed and lower voltage operation compared to bulk CMOS.
3) Potential applications discussed include low power digital devices, radio frequency circuits where reduced capacitance enables better high-frequency performance, and mixed-signal chips where substrate isolation reduces interference.
This document discusses ultra thin body SOI FETs. Some key points:
- SOI uses a thin silicon layer on an insulating substrate to reduce parasitic capacitance and improve performance over bulk silicon. Fully depleted SOI is preferred for its thin size and reduced leakage/power consumption.
- Benefits of SOI include lower capacitance, resistance to latch-up, higher performance at lower voltages, reduced temperature effects, better yields, and reduced leakage currents.
- Ultra thin body SOI FETs have even better gate control and mobility due to thin channel thickness, lower parasitic capacitance, and reduced leakage currents, making them useful for applications like memory, microelectronics, RF devices,
Ultra-thin body SOI MOSFETs: Term Paper_class presentation on Advanced topics...prajon
This document discusses ultra-thin body SOI MOSFETs. It describes how SOI technology uses a layered silicon-insulator-silicon substrate to improve performance and reduce short-channel effects compared to conventional silicon. Ultra-thin body SOI can further suppress short-channel effects and reduce sub-threshold gate leakage. The document examines the effects of body doping, buried oxide thickness, inversion charge, and mobility on ultra-thin body SOI MOSFET performance. It concludes that ultra-thin body SOI with high-k gate dielectrics can improve scaling and performance for high-density, low-power applications.
The document discusses different methods of well formation in CMOS devices, including N well formation, P well formation, and twin tub formation. Twin tub formation allows for separate optimization of N-type and P-type transistors by providing independent control over threshold voltage, body effect, and gain for each transistor type. The twin tub formation process involves starting with a lightly doped substrate and forming an epitaxial layer to prevent latch up. P-wells and N-wells are then formed through a process using photoresist masks, boron and phosphorus implants, and oxide layers.
Fabrication of silicon on insulator (soi)Pooja Shukla
The document discusses the fabrication of photonic crystals using 248 nm deep UV lithography. It involves using a SOI wafer and performing lithography to selectively pattern and etch the silicon layer to create a photonic crystal structure. Deep UV lithography allows fabrication of wavelength-scale nanostructures but can be impacted by optical proximity effects between neighboring patterns which can alter feature sizes. Proximity correction techniques are discussed to help mitigate these effects and allow mass production of photonic integrated circuits using this method.
The twin well process allows for separate optimization of n-type and p-type transistors. It involves depositing a lightly doped epitaxial layer on an n+ or p+ substrate, then forming n-wells and p-wells in this layer through independent doping steps. This allows the dopant concentrations to be carefully tuned to produce desired device characteristics for both transistor types. The key steps are tub formation through n-well and p-well implantation and diffusion, polysilicon gate formation, and contact definition and metallization to connect the transistors. The main advantage is obtaining balanced performance from n-type and p-type transistors through separate well optimization.
This document discusses silicon on insulator (SOI) technology. It begins by defining SOI as using a layered silicon-insulator-silicon substrate instead of conventional silicon substrates in semiconductor manufacturing. It then explains the differences between bulk silicon MOSFETs and SOI MOSFETs. The document discusses several manufacturing methods for SOI, including SIMOX, wafer bonding, and Smart Cut. It also covers the benefits of SOI such as lower parasitic capacitance and resistance to latch-up. Finally, it distinguishes between partially depleted SOI and fully depleted SOI devices.
twin well cmos fabrication steps using Synopsys TCADTeam-VLSI-ITMU
The document describes the design and simulation of a CMOS fabrication process using TCAD (Technology Computer-Aided Design). It involves dimensioning the design using MOSIS design rules, creating masks, and defining 44 steps for the process in Synopsys TCAD. This includes doping wells, growing oxides, depositing polysilicon, implanting sources and drains, and depositing metals. The process aims to fabricate n-well and p-well CMOS on a silicon substrate using a minimum number of masks. Characterization and optimization of the modeled device can be done using additional TCAD tools.
This document summarizes the design of distributed amplifiers in 130nm CMOS SOI technology. Distributed amplification provides flat frequency response from DC to several GHz by combining the gain of active devices with transmission lines. The designed circuits include a common source distributed amplifier with floating body transistors achieving 7dB gain over 0.4-30GHz, and a cascode distributed amplifier with 6.8dB gain over 0.4-27GHz and improved matching. Performance comparisons show the benefits of SOI CMOS for wideband applications.
The document discusses CMOS VLSI design technology and future trends. It provides an overview of CMOS technology and basic MOSFET operation. It then discusses how nanotechnology and integrated tri-gate transistors can help address limitations of CMOS scaling by reducing feature sizes and parasitic leakage. The document concludes that continued CMOS scaling will eventually be limited and alternatives like nanotechnology may be needed to retain device characteristics at smaller sizes.
Nanotechnology involves engineering materials at the nanoscale, around 1 to 100 nanometers. Richard Feynman is considered the father of nanotechnology. Nanotechnology has applications in many fields including electronics, computing, medicine, cosmetics, foods, the military, and energy. By 2020, products with nanotechnology components could be worth $1 trillion. Materials behave differently at the nanoscale compared to larger scales due to statistical mechanics and quantum effects. Nanotechnology is approached through top-down methods like lithography or bottom-up methods like self-assembly.
Nanoscale Based Digital VLSI Circuits (1) - NEHA PATEL.pptx.pdfbatpad
This document discusses nanoscale-based digital VLSI devices and the future of semiconductor technology. It describes how nanoscale devices like FinFET transistors, carbon nanotubes, nanowire transistors, and quantum dots can enable smaller, faster, and more energy efficient circuits. Some challenges with nanoscale device integration are manufacturing precision, variability, and reliability. The document outlines several future trends for nanoscale technologies like miniaturization, post-CMOS devices, 3D integration, and biologically inspired circuits.
Viii. molecular electronics and nanoscienceAllenHermann
This document discusses molecular electronics and nanoscience. It begins by explaining why molecular electronics is an important area of research, as Moore's Law means devices will soon reach the molecular scale. It then describes two approaches to fabrication: top-down, continuing to shrink bulk semiconductor devices; and bottom-up, designing molecules with electronic function that can self-assemble. The document discusses various molecular systems and materials that could form the basis for single-molecule devices, including examples of molecules that could act as switches, sensors, or memory cells. It also reviews techniques for measuring conduction at the single-molecule level.
The document discusses various types of nano devices and their operation. It describes resonant tunneling diode (RTD) which consists of a double barrier structure and exhibits peaks and valleys in current as electron energy passes quantum bound states. Resonant tunneling transistor (RTT) controls large current using small gate voltage. A single-electron transistor (SET) switches current using single electron charge on its gate. Other devices discussed include fin-shaped field-effect transistor (FinFET) and nanowire field-effect transistor (nanowire FET) which have better control of the channel using their 3D gate structure. Nano devices are used in various fields including medical, military and agriculture.
The document provides information on IC technology, including Moore's Law, the cost of fabrication, what a silicon chip is, switches, semiconductors and doping, IC technologies, MOS transistors, fabrication technology, CMOS technology, BiCMOS, semiconductor fabrication processes like lithography, etching, deposition, chemical mechanical planarization, oxidation, ion implantation, and diffusion. It also discusses the basic processes for NMOS and CMOS fabrication, including starting with a silicon wafer and using masks and steps like oxidation, deposition, doping, and etching to build the transistors.
This document discusses MOSFET scaling and emerging nanoelectronic devices. It begins by outlining the objectives and introducing MOSFET scaling and its limits. It then describes techniques used for continued MOSFET scaling like strained silicon and high-k dielectrics. Emerging devices like FinFETs, organic field-effect transistors, and single electron transistors are also summarized. Fabrication processes for devices like TiOx single electron transistors using STM oxidation are briefly outlined.
The document discusses carbon nanotube field-effect transistors (CNTFETs) as an alternative to MOSFETs. It notes that continued scaling of MOSFETs faces challenges like short channel effects and high leakage currents. CNTFETs offer potential advantages like ballistic transport and high mobility. The document describes the basic structure and working of different types of CNTFETs, including bottom-gate, top-gate, coaxial gate, Schottky-barrier, and MOSFET-like devices. It compares key metrics of CNTFETs like transconductance and drive current to MOSFETs. In conclusion, CNTFETs show promise for high performance if manufacturing challenges can be addressed.
Please read the following IEEE Spectrum articles and answer the quest.pdffasttrackcomputersol
Please read the following IEEE Spectrum articles and answer the questions given. You may
want to use illustrations in your answer to the questions, and mark them up accordingly as part of
answering the questions. If you take illustrations from some source (including the IEEE
Spectrum articles) please make sure this is properly cited.
http://spectrum.ieee.org/semiconductors/nanotechnology/the-next-highperformance-transistor-
could-be-made-from-lateral-nanowires Describe a FINFET and how it works. How is it different
than the planar MOSFET described in the first 5 slides of the TFET lecture? Is the FINFET a
quantum device? Give reasons why or why not. How is the nanowire device described here
different than the FINFET? Why is this difference an advantage for the nanowire device? They
one problem with the nanowire device is capacitive coupling. What is this and explain why it is a
problem with the nanowire device?
Solution
1)
The FinFET technology promises to provide the deliver superior levels of scalability needed to
ensure that the current progress with increased levels of integration within integrated circuits can
be maintained.
The FinFET offers many advantages in terms of IC processing that mean that it has been adopted
as a major way forwards for incorporation within IC technology.
FinFET technology has been born as a result of the relentless increase in the levels of
integration. The basic tenet of Moore\'s law has held true for many years from the earliest years
of integrated circuit technology. Essentially it states that the number of transistors on a given
area of silicon doubles every two years.
Some of the landmark chips of the relatively early integrated circuit era had a low transistor
count even though they were advanced for the time. The 6800 microprocessor for example had
just 5000 transistors. Todays have many orders of magnitude more.
basically what is finfet??
FinFET technology takes its name from the fact that the FET structure used looks like a set of
fins when viewed.
The main characteristic of the FinFET is that it has a conducting channel wrapped by a thin
silicon \"fin\" from which it gains its name. The thickness of the fin determines the effective
channel length of the device.
In terms of its structure, it typically has a vertical fin on a substrate which runs between a larger
drain and source area. This protrudes vertically above the substrate as a fin.
The gate orientation is at right angles to the vertical fin. And to traverse from one side of the fin
to the other it wraps over the fin, enabling it to interface with three side of the fin or channel.
This form of gate structure provides improved electrical control over the channel conduction and
it helps reduce leakage current levels and overcomes some other short-channel effects..
The term FinFET is used somewhat generically. Sometimes it is used to describe any fin-based,
multigate transistor architecture regardless of number of gates.
Due to the increased emphas.
The document discusses basic concepts in VLSI design including:
- The history and progression of integrated circuit generations from SSI to VLSI to ULSI.
- The basic operation and types (enhancement vs depletion, NMOS vs PMOS) of MOS transistors.
- Fabrication processes for CMOS, including masks, diffusion, deposition of oxide and polysilicon layers.
- Threshold voltage and factors that determine it such as oxide thickness and charges at interfaces.
The document provides tips for doing well in VLSI design such as attending classes regularly, working independently on assignments, studying effectively in groups, asking questions, and not cheating on exams. It also discusses various steps in the VLSI design flow including front-end design, back-end design, and considerations for power, timing, and area. Students are encouraged to study thoroughly from textbooks and notes to learn rather than just studying for exams.
This document provides an overview of nanoelectronics. It defines nanoelectronics as a branch of engineering that uses electronic components with dimensions measured in nanometers. The document discusses how nanoelectronics can be used to reduce the size of electronic devices. It also outlines several applications of nanoelectronics in electronics, energy, and displays. Finally, it discusses future opportunities for nanoelectronics in areas like flexible electronics, wireless devices, and molecular devices.
Molecular electronics utilizes single molecules or collections of molecules as electronic components. It offers the potential to continue shrinking circuits beyond the limits of silicon as dictated by Moore's law. Molecular electronics relies on organic polymers, polyphenylene chains, and carbon nanotubes as its molecular building blocks. These molecules can act as wires, transistors, diodes, and other circuit elements. Successful demonstrations include organic field-effect transistors and molecular memory chips. Molecular electronics promises greater miniaturization, lower power usage, and new applications like flexible electronics if the challenges of precise fabrication and experimental verification can be overcome.
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This document discusses mesoscopic structures, which have sizes between the macroscopic and microscopic scales (usually a few nanometers to 100 nm). At these length scales, materials can exhibit new properties due to their dimensions being similar to characteristic lengths like the de Broglie wavelength. Coherent transport and quantum interference effects are also described, which influence electrical conductance. Applications of quantum interference include SQUIDs, quantum cryptography, and quantum computing. The document also discusses carbon nanotubes, their properties, classification as single-walled or multi-walled, and various applications from displays to hydrogen storage.
M. Meyyappan provides an overview of recent developments in nanotechnology at NASA Ames Research Center. The center's research focuses on carbon nanotubes, molecular electronics, inorganic nanowires, and protein nanotubes. Applications being developed include nanoelectronics, sensors, gene sequencing using nanopores, and microscopy using carbon nanotube tips. Challenges include controlling material properties at the nanoscale and developing large-scale production methods.
Plasmonics aims to merge photonics and electronics at the nanoscale by using surface plasmons. Surface plasmons are electromagnetic waves that propagate along metal surfaces and can confine light to subwavelength dimensions, allowing the miniaturization of photonic components. This makes it possible to integrate optical and electronic circuits on the same chip. Plasmonic circuits use various geometries like thin metal films and arrays of gold nanoparticles as waveguides to guide surface plasmon signals while avoiding losses. This could enable the development of miniaturized optoelectronic components and circuits with subwavelength features bridging the gap between photonics and electronics.
Nanotechnology involves manipulating materials at the atomic or molecular scale to create structures between 1 to 100 nanometers in size and endow them with new properties. It has applications in electronics, medicine, energy, and other fields. Some key points are that it allows integrating biology, chemistry and engineering to build devices with unprecedented properties. Challenges include developing new research tools and cleanroom infrastructure since nanoscale work requires precision. The future of nanotechnology may include flexible electronics, molecular devices, and applications like enhanced health monitoring and energy storage.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
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Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
2. Evolutionary advances beyond CMOS
• Evolutionary approaches-Silicon on Insulator, Dual gate FETs and SiGe
structures.
• SOI
– Consists of thin SiFET structure grown on a buried SiO2 layer which is in turn grown on a
Si substrate.
– Complete electrical isolation,
– Eliminating latch up between adjacent devices (electrical behavior (electrical
interaction can occur between neighboring tubs and/or the substrate) of one
device affects that of a neighboring device),
– Rad-hard or radiation hardness-Highly immune to radiation induced failure,
such as soft errors (change in logic state of a device due to the accumulation
of charge resulting from carrier generation following the transit of a high
energy particle or ionizing radiation through the device),
– Immune to short channel effects than standard CMOS,
3.
4.
5.
6. • Two different manner SOI devices are operated (depending on
thickness of Si layer and its doping concentration)
• Partially
• Fully depleted
– Partially depleted SOI devices
• Made with thicker Si active layers
• Disadvantage is body charging
– Fully Depleted SOI devices
• Thin active layer and the doping concentration sufficiently low that it is depleted of
free carriers.
7.
8.
9. • Dual gate FET
– Short channel effects are reduced
– Reduce the drain-induced barrier lowering and minimize threshold sensitivity to the
channel
– Relative Scaling advantage of about a factor of 2 over conventional CMOS devices
– Disadvantage presence of two si-sio2 interfaces from two gates increases the surface
roughness scattering. As a result the carrier mobility is reduced thus lowering the
frequency of operation of the device.
– Two different types of dual gate MOSFET structures -Symmetric and asymmetric gated
devices
• Surface channels turn on at same gate voltages -Same work function
• Surface channels turn on at different gate voltages - different work function
– Three different ways in which dual gate MOSFET can be made
• With top and bottom gates formed parallel to the plane of the substrate. In this configuration the source and
drain regions straddle the two gates and the current flow in the channel runs parallel to the substrate.
• Vertical dual gate FETs the gates are perpendicular to the substrate and the current runs parallel to the
substrate- FinFET
• Si and Si-Ge together to form heterostructure.The enhanced electron mobility within the strained Si acts to
increase the speed of the SiGe MOSFET. Therefore, strained Si-SiGe MOSFETs have an intrinsically higher
transconductance and thus higher frequency of operation than conventional MOSFETs.
10. WHAT IS SHORT CHANNEL
• Channel length ~= depletion width of source and drain
• Short channel MOS has good processing speed, requires low operating potential and
increases transistor density on the chip.
• Although the performance degrades with decrease in channel length.
• It faces some serious issues like DIBL, surface scattering, velocity saturation, impact
ionisation, hot electron effect
12. SURFACE SCATTERING
• In long channel Ex>>Ey, but in short channel Ex is not negligible.
• Ex and Ey field makes electron to travel in zig-zag path, reducing their mobility.
• As the channel length becomes shorter electric field Ey increases causing surface
mobility to become field dependent.
13.
14. Carbon nanotubes
• Very small graphite sheets rolled into a seamless cylinder. Nano tubes are
very thin and are long macro molecules of carbon.
• Nano tubes can be either multi walled or single walled.
– Multiwalled nanotubes consists of concentric cylinders wrapped around each
other while single walled nanotubes consists only of one layer.
15. • Nanotubes can act as metal or semiconductor depending upon the
diameter of the tube and its helicity, or degree to which the carbon spirals
around the tube. Large diameter – semi metal; narrow diameter-
semiconductor.
• The energy band gap of a carbon nano tube depends mainly upon the
diameter of the tube; the larger the diameter the smaller the energy gap.
• Mechanically they have largest strength to weight ratios of any material.
• Very high thermal conductance, close to diamond making them efficient
heat conductors. Nano tubes can be used to cool very dense arrays of
devices.
• Nano tube may provide an alternative interconnect material that has a
high thermal conductivity, and can thus help in dissipating heat in a highly
packed circuit.
• Nano tubes can support extremely high current densities without any
electro migration problems.
• Nano tubes may find usefulness as inter connects. Their very small
diameter and high conductivity make them attractive for wires in an ICs.
• Make emitters for compact, flat panel displays (emit electrons at lower
applied voltages)
• Fabrication of nanotube FETs presently is done one at a time with great
efforts, making them unattractive for high density circuits.
16. • Nano tube FET device
In this structure a single SWCNT was used to bridge two noble metal electrodes
prefabricated by lithography on an oxidized silicon wafer. Here the SWCNT plays the
role of channel and the metal electrodes act as source and drain. The heavily doped
silicon wafer itself behaves as the back gate. These CNTFETs behaved as p-type
FETs with an I (on)/I(off) ratio~105. This suffers from some of the limitations like high
parasitic contact resistance (=1Mohm), low drive currents (a few Nanoamperes), and
low transconductance. To reduce these limitations the next generation CNTFET
developed which is known as top gate CNTFET.
18. Conventional Computers
• Conventional computers are machines that follow a well
described set of instructions to process data.
• Basically, a set of instructions is read into the machine and it
works sequentially in an ordered way to execute a task.
• often referred to as Von Neumann computers or classical
machines.
• major components are
– memory,
– processing, and
– bandwidth.
19. Continued…..
• Can be thought of as structurally programmable machines.
This means that the program controls the behavior of the
machine.
• A compiler translates the input code into machine language
that is expressed in terms of the states of simple switching
devices and their connections.
• The machine computes symbolically and the result depends
to some extent upon the human input.
Well suited to number crunching, communication, and data
manipulation.
19
20. Problems
• pattern recognition
– Specifically, it is very difficult to program a classical computer to recognize
a complicated molecule or distinguish between different microorganisms.
• In the chemical and biological world pattern recognition is highly
efficient and readily accomplished.
– For example, the immune system in the human body. This behavior is an
example of a different type of computing, which we will refer to as tactile
computing.
20
21. Tactile Computing
• These machines are not structurally programmable.
• In Bio molecular computing, pattern processing is physical and
dynamic as opposed to the symbolic and passive processing in a
conventional machine.
• Programming depends upon evolution by variation and
selection. Such a molecular computer is called a tactile
processor.
• A tactile processor can be thought of as a computer driven by
enzymes; the inputs are converted into molecular shapes that
the enzymes can recognize.
• Enzyme thus performs sophisticated pattern recognition since it
scans the molecular objects within its environment, interacting
with only those molecules that have a complementary shape
• Recognition is thus a tactile procedure.21
22. Examples
1) An example of tactile computer-
– A variety of bacteria bred to dissolve oil spills.
– the bacteria would be “programmed” by altering its DNA.
– the unique and powerful information processing capabilities of life,
pattern and object recognition, self-organization and learning, and
effective use of parallelism are harnessed.
2) sensing bioagents or toxins.
– Molecules can be used to perform complicated pattern recognition of
dangerous toxins released into the air or water.
– Even Very dilute amounts can be identified readily.
– Can be used to fight terrorist bioattacks, or chemical warfare.
• The “program” is in the molecule itself; the computation occurs
by the recognition of one molecule by an enzyme and their
subsequent chemical reaction.
• Next we will examine tactile computing using biological systems,
DNA, and molecules.
22
23. Biomolecular Computing
• Biological systems are a special case of molecular computing(broader
context).
• Major qualities of molecules that make their potential usage in future
applications attractive are that they offer simplified fabrication, low cost
and relatively unlimited availability, and devices made from molecules are
very much smaller and compact than existing CMOS structures.
• For example
– A CMOS OR gate requires any where from 4-6 orders of magnitude more
surface area than a comparable molecular logic gate.
– Molecular electronic offers extremely compact computing capability,i.e
Microprocessor on a pinhead. Coupled with their expected lower power
consumption and relatively inexpensive to fabricate and mass produce.
23
24. key advantages of molecular materials
• Size: on average they are about 4 nm. These device dimensions are about
two orders of magnitude smaller than that which can be obtained using
SiCMOStechnology.
• Three-dimensional structures: In contrast, in Si based technology, much
fabrication effort and cost is required to produce three-dimensional
geometries.
• High packing density: the combined features of small size and three-
dimensionality make very high packing densities possible. It is estimated
that the packing density can be increased by 6–9 orders of magnitude
over CMOS.
• Bistability and nonlinearity: bistability and nonlinearity can be utilized to
perform switching functions. Both of these properties are commonly
available in molecules.
• Anisotropy: the electronic and optical properties of a molecule are
inherent in the molecular structure instead of being fabricated by the
processing technologies as in CMOS.
24
25. Continued…..
• Upward construction: organic synthesis enables growth of
microstructures from the small upward. In standard CMOS, device and
circuit functionality is sculpted from a relatively large piece of material.
• Self-organization: self-organization, self-synthesis, and redundancy
factors well known in organic and biological molecules that could
potentially be applied to molecular electronic devices.
• Low power dissipation: Estimates are that the total power requirements
for molecular switches will be about five orders of magnitude lower than
for CMOS switches.
• Molecular engineering: it is possible that molecules can be tailored or
engineered(can be selectively grown and made to inherently possess
desired qualities to perform a task.) to perform specific tasks or have
specific properties.
The above features of molecules also apply to biomolecules.
25
26. Bio molecules
• Bio molecules provide parallel environment for computation, they occur
abundantly in nature and their implementation due to self organization and
upward construction is relatively simple compared with the difficult and costly
fabrication of CMOS circuitry.
• As mentioned size is a key advantage of molecules.
– The entire genetic code for humans is contained in the nucleus of most cells.
– The DNA Code consists of over three billion nucleotide pairs and fits into a few double helices about
3.4nm in width and measuring micrometers in length.
26
27. DNA-an overview
• The entire genetic code for humans is contained in the
nucleus of most cells.
• The DNA code consists of over three billion nucleotide pairs
and fits into a few double helices about 3.4 nm in width and
measuring micrometers in length.
27
28. • Researchers are developing what are called applets for biological
systems.
• These applets enable the system to respond to an external event,
“program” a cell to produce a desired chemical or enzyme, or
enable a cell to identify a reagent.
• Some potential applications of biological applets:
– In gene therapy for treating diseases such as hemophilia,
anemia, etc.
– in the treatment of diabetes( A genetic applet can be used
that senses the glucose level in the blood and another applet
can then direct the production and release of insulin if
needed.).
28
29. • DNA molecules
are composed of
four basic nucleic
acids called
– adenine (A), guanine (G),
cytosine (C) and thymine
(T).
– A and T, and C and G
naturally bond together
to form pairs.
29
30. Computation with DNA
• To compute with DNA there are three basic steps.
– encoding that maps the problem onto DNA strands,
– basic processing using a chemical process called
hybridization that connects two complementary DNA
strands into a double strand,
– and outputting the results.
Programming DNA involves the usage of DNA tiles.
• These tiles consist of multiple strands of DNA knotted
together.
• The ends of each tile are created such that the tile will
recognize and attach to other pre-designed tiles to make self-
assembled structures.
• These tiles can be used to add or multiply numbers30
31. Drawbacks
• These are basically related to the difficulty encountered in
regulating or controlling the basic chemistry.
– Reliability means the degree of confidence in correctly
solving a problem.
– Efficiency is related to the effective manipulation of the
molecules used to perform the computation.
– Scalability is the successful reproduction of the desired
event many times.
31
32. Moletronics-molecular diodes and diode-diode logic
• Both conducting and insulating molecules are needed to form
devices.
• Two most conducting molecular species are polyphenylenes
and carbon nanotubes.
• Polyphenylenes are chain like molecules formed by linking a
basic molecular unit, C6H4 , phenylene, which is a derivative of
the benzene ring but with two free binding sites
33. • Molecules can also be used to build devices that mimic CMOS
functionality.
• Molecular diodes and other quantum based devices have
been designed.
• The primary components of these molecular structures are
conducting groups called polyphenylenes and insulating
groups called aliphatic molecules.
• By arranging these molecules in various orders similar device
action to that found in semiconductors can be attained.
• These structures can be combined to make various logic gates
such as NOR and NAND gates.
33
34. Defect tolerant computing
• Wherein the operation of a computer can be maintained even if part of its
hardware is defective.
• Yield of the chips, defined as the percentage of perfectly operating chips vs the
total number made on the die, decreases with increasing chip complexity.
• The ability to configure a chip to operate around defects and imperfections would
greatly improve the manufacturing yield and consequently the cost of the chips.
• Existing computing hardware paradigm is that the chip must function in all
applications perfectly ( perfect performance).
• The perfectly operating chip paradigm is not the only possibility for computing
hardware. It is conceivable that flawed chips can still be used provided that the
defective components in the chip are known in advance and are thereby avoided
during chip’s operation. Such an approach is called defect tolerant computing.
• Teramac 10^12 operations per second-many defective chips could be connected12 operations per second-many defective chips could be connected
to produce a powerful yet very inexpensive parallel computer.to produce a powerful yet very inexpensive parallel computer.
• Family tree like branching architecture and fat-tree architecture.Family tree like branching architecture and fat-tree architecture.
• Teramac utilizes Fat-tree architecture.Teramac utilizes Fat-tree architecture.