Tài liệu Nano and Microelectromechanical Systems P1 ppt

CHAPTER 1

NANO- AND MICROENGINEERING,

AND NANO- AND MICROTECHNOLOGIES

1.1. INTRODUCTION

The development and deployment of NEMS and MEMS are critical to the

U.S. economy and society because nano- and microtechnologies will lead to

major breakthroughs in information technology and computers, medicine and

health, manufacturing and transportation, power and energy systems, and

avionics and national security. NEMS and MEMS have important impacts in

medicine and bioengineering (DNA and genetic code analysis and synthesis,

drug delivery, diagnostics, and imaging), bio and information technologies,

avionics, and aerospace (nano- and microscale actuators and sensors, smart

reconfigurable geometry wings and blades, space-based flexible structures, and

microgyroscopes), automotive systems and transportation (sensors and

actuators, accelerometers), manufacturing and fabrication, public safety, etc.

During the last years, the government and the high-technology industry have

heavily funded basic and applied research in NEMS and MEMS due to the

current and potential rapidly growing positive direct and indirect social and

economic impacts.

Nano- and microengineering are the fundamental theory, engineering

practice, and leading-edge technologies in analysis, design, optimization, and

fabrication of NEMS and MEMS, nano- and microscale structures, devices,

and subsystems. The studied nano- and microscale structures and devices

have dimensions of nano- and micrometers.

To support the nano- and microtechnologies, basic and applied research

and development must be performed. Nanoengineering studies nano- and

microscale-size materials and structures, as well as devices and systems, whose

structures and components exhibit novel physical (electromagnetic and

electromechanical), chemical, and biological properties, phenomena, and

processes. The dimensions of nanosystems and their components are 10-10 m

(molecule size) to 10-7 m; that is, 0.1 to 100 nanometers. Studying

nanostructures, one concentrates one’s attention on the atomic and molecular

levels, manufacturing and fabrication, control and dynamics, augmentation and

structural integration, application and large-scale system synthesis, et cetera.

Reducing the dimensions of systems leads to the application of novel materials

(carbon nanotubes, quantum wires and dots). The problems to be solved range

from mass-production and assembling (fabrication) of nanostructures at the

atomic/molecular scale (e.g., nanostructured electronics and actuators/sensors)

with the desired properties. It is essential to design novel nanodevices such as

nanotransistors and nanodiodes, nanoswitches and nanologic gates, in order

to design nanoscale computers with terascale capabilities. All living biological

systems function due to molecular interactions of different subsystems. The

molecular building blocks (proteins and nucleic acids, lipids and

carbohydrates, DNA and RNA) can be viewed as inspiring possible strategy

on how to design high-performance NEMS and MEMS that possess the

properties and characteristics needed. Analytical and numerical methods are

available to analyze the dynamics and three-dimensional geometry, bonding,

and other features of atoms and molecules. Thus, electromagnetic and

mechanical, as well as other physical and chemical properties can be studied.

Nanostructures and nanosystems will be widely used in medicine and

health. Among possible applications of nanotechnology are: drug synthesis

and drug delivery (the therapeutic potential will be enormously enhanced due

to direct effective delivery of new types of drugs to the specified body sites),

nanosurgery and nanotherapy, genome synthesis and diagnostics, nanoscale

actuators and sensors (disease diagnosis and prevention), nonrejectable nano￾artificial organs design and implant, and design of high-performance

nanomaterials.

It is obvious that nano- and microtechnologies drastically change the

fabrication and manufacturing of materials, devices, and systems through:

• predictable properties of nano composites and materials (e.g., light

weight and high strength, thermal stability, low volume and size,

extremely high power, torque, force, charge and current densities,

specified thermal conductivity and resistivity, et cetera),

• virtual prototyping (design cycle, cost, and maintenance reduction),

• improved accuracy and precision, reliability and durability,

• higher degree of efficiency and capability, flexibility and integrity,

supportability and affordability, survivability and redundancy,

• improved stability and robustness,

• higher degree of safety,

• environmental competitiveness.

Foreseen by Richard Feyman, the term “nanotechnology” was first used

by N. Taniguchi in his 1974 paper, "On the basic concept of

nanotechnology." In the last two decades, nanoengineering and

nanomanufacturing have been popularized by Eric Drexler through the

Foresight Institute.

Advancing miniaturization towards the molecular level with the ultimate

goal to design and manufacture nanocomputers and nanomanipulators

(nanoassemblers), large-scale intelligent NEMS and MEMS (which have

nanocomputers as the core components), the designer faces a great number of

unsolved problems.

Possible basic concepts in the development of nanocomputers are listed

below. Mechanical “computers” have the richest history traced thousand

years back. While the most creative theories and machines have been

developed and demonstrated, the feasibility of mechanical nanocomputers is

questioned by some researchers due to the number of mechanical

components (which are needed to be controlled), as well as due to unsolved