RAJASTHAN TECHNICAL UNIVERSITY, KOTA (Electronics & Communication) Submitted By: LAKSHIKA SOMANI E&C II yr, IV sem. Session: 2007-08 Department of Electronics & Communication Geetanjali Institute of Technical Studies Dabok, Udaipur 1
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Contents INTRODUCTION SEMICONDUCTOR ELECTRONICS DISADVANTAGES OF SEMICONDUCTOR ELECTRONICS MOTIVATION FOR NANOELECTRONICS NANOTECHNOLOGY / NANOELECTRONICS NANOELECTRONICS AIMS OF NANOELECTRONICS APPROACHES TO NANOELECTRONICS FUTURE NANOELECTRONIC DEVICES 3
INTRODUCTION 4
Semiconductor electronics SIZE & COST: Exponential Decrease PERFORMANCE & INTEGRATY: Exponential Increase 5
Electronics in next 30 Years 6
DISADVANTAGES OF SEMICONDUCTOR ELECTRONICS Quantum and coherence effects, High electric fields and Heat dissipation problems in closely packed structures 7
MOTIVATION FOR NANOELECTRONICS Limits of Conventional CMOS technology Device physics scaling Interconnects Nanoelectronic alternatives? Negative resistance devices, switches (RTDs, molecular), spin transistors Single electron transistor (SET) devices and circuits Quantum cellular automata (QCA) New information processing paradigms Quantum computing, quantum info processing (QIP) Sensing and biological interface Self assembly and biomimetric behavior Issues Predicted performance improves with decreased dimensions, BUT Smaller dimensions-increased sensitivity to fluctuations Manufacturability and reproducibility 8
Nanotechnology / Nanoelectronics Nanotechnology is the design and construction of useful technological devices whose size is a few billionths of a meter Nanoscale devices will be built of small assemblies of atoms linked together by bonds to form macro-molecules and nanostructures Nanoelectronics encompasses nanoscale circuits and devices including (but not limited to) ultrascaled FETs, quantum SETs, RTDs, spin devices, superlattice arrays, quantum coherent devices, molecular electronic devices, and carbon nanotubes. 9
NANOELECTRONICS Nanoelectronics refer to the use of nanotechnology on electronic components, especially transistors. Nanoelectronics are sometimes considered as disruptive technology because present candidates are significantly different from traditional transistors. Nanoelectronics is where Physics, Material Science, Chemistry & Electrical Engineering inevitably meet. 10
AIMS OF NANOELECTRONICS To Process, transmit and store information by taking advantage of properties of matter that are distinctly different from macroscopic properties. It is not only to manufacture minute structures but also to develop innovative systems for effective integration of billions of devices 11
The relevant length scale depends on the phenomena investigated: It is a few nm for molecules that act like transistors or memory devices, and can be 999 nm for quantum dot where the spin of the electron is being used to process information. 12
Microelectronics, even if the gate size of the transistor is 50 nm, is not an implementation of nanoelectronics, as no new qualitative physical property related to reduction in size are being exploited. 13
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APPROACHES TO NANOELECTRONICS Nanofabrication Nanofabrication can be used to construct ultradense parallel arrays of nanowires, as an alternative to synthesizing nanowires individually. 16
Nanowires A nanowire is a wire of diameter of the order of a nanometer (10 9 meters). Nanowires can also be defined as structures that have a lateral size constrained to tens of nanometers or less and an unconstrained longitudinal size. 17
SEMICONDUCTOR NANOWIRES 18
Nanomaterials electronics Besides being small and allowing more transistors to be packed into a single chip, the uniform and symmetrical structure of nanotubes allows a higher electron mobility (faster electron movement in the material), a higher dielectric constant (faster frequency), and a symmetrical electron/hole characteristic. 19
Nanotubes 20
Nanotubes Nanotubes are members of the fullerene structural family a nanotube is cylindrical,, with at least one end typically capped with a hemisphere of the buckyball structure Their name is derived from their size, since the diameter of a nanotube is in the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to several millimeters in length. Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). 21
Molecular electronics Molecular electronics is a new technology which is still in its infancy, but also brings hope for truly atomic scale electronic systems in the future.. 22
Other approaches Nanoionics studies the transport of ions rather than electrons in nanoscale systems. Nanophotonics studies the behavior of light on the nanoscale. 23
FUTURE NANOELECTRONIC DEVICES 24
COMPUTERS Nanoelectronics based computer processors using nanowires and carbon nanotubes are more powerful than those with conventional semiconductor fabrication techniques. 25
ENERGY PRODUCTION Cheaper and more efficient solar cells with the use of nanowires and other nanostructured materials than are possible with conventional planar silicon solar cells. There is also research into energy production for devices that would operate in vivo,, called bio- nano generators. 26
MEDICAL DIAGNOSTICS Nanoelectronic devices that could detect the concentrations of biomolecules in real time for use as medical diagnostics, thus falling into the category of nanomedicine. Nanoelectronic devices which could interact with single cells for use in basic biological research. These devcies are called nanosensors. 27
OTHERS Fabrication and characterization of individual components to replace the macroscopic silicon components with nanoscale systems. Investigation of potential interconnects. 28
The Nanoscale Mantra 29
Than k you 30