Semiconductor Materials for Electronics

MATERIALS,
SEMICONDUCTOR MATERIALS,
and MICROELECTRONICS
Materials science..
..is primarily concerned with the search of basic knowledge about the internal
structure, properties, and processing of materials.
Materials engineering..
..is mainly concerned with the use of fundamental and applied knowledge of
materials so that the materials can be converted into products needed or desired by
society.
Materials science and engineering..
..combines both materials science and materials engineering.
Types of materials
Most engineering materials are divided into three main or fundamental classes;
Metallic materials
Polymeric materials
Ceramic materials
Additional application classes;
Composite materials
Electronic materials
Metallic materials..
..(metals and metal alloys) are inorganic materials that are characterized by high
thermal and electrical conductivities. Examples are iron, steel, aluminum, copper.
Polymeric materials..

.are materials consisting of long molecular chains or network of low weight elements
such as carbon, hydrogen, oxygen, and nitrogen. Most polymeric materials have low
electrical conductivities. Examples are polyethylene, polyvinyl chloride (pvc).
Ceramic materials..
..are materials consisting of compounds of metals and nonmetals. Ceramic materials
are usually hard and brittle. Examples are clay products, glass, and pure aluminum
oxide that has been compacted and densified.
Composite materials..
.. are materials that are mixtures of two or more materials. Examples are fiberglass
reinforcing material in a polyester or epoxy matrix.
Electronic materials..
..are materials used in electronics especially microelectronics. Examples are silicon,
gallium arsenide.
Nanomaterials..
..are materials with a characteristic length scale smaller than 100 nm.
Assignment 1
Consider a lightbulb.
(a) Identify various critical components of a lightbulb.
(b) Determine the material selected for each critical component.
(c) Rationalize why the material was selected for each component.

Semiconductor materials..
..are nearly perfect crystalline solids with small amount of imperfections, such as
impurity atoms, lattice vacancies, or dislocations, which are sometimes intentionally
introduced to alter their electrical characteristics
A summary of the chemical elements involved in the formation of semiconductors.
The semiconductors can be elemental, such as Si, Ge, and other chemical
elements from group IV.
They can be also compound, a combination between elements from group III and
group V, or respectively, from group II and group VI.
Examples for such combinations are the binary compounds GaAs and ZnS.
There are also several combinations of practical importance, which involve two or
more elements from the same chemical group.
Such alloy semiconductors can be binary (e.g. SiGe ), ternary (e.g. AlGaAs ),
quaternary (e.g. InGaAsP), and even pentanary (GaInPSbAs) materials.

Electronic materials include insulators, semiconductors, conductors, and
superconductors.
This family of materials has truly revolutionalized the world. From spark plugs made
from alumina, and copper wires for electrical transmission to components for
wireless communications, high powered magnets used in magnetic resonance
imaging, capacitors, inductors, solar cells, active matrix displays, silicon, and gallium
arsenide based computer chips, electronic materials are found in countless numbers
of applications.
New advances in the materials sciences have led to several breakthroughs in the
developement of new electronic materials. We now have ceramics that are not just
excellent insulators, but also semiconductors and superconductors. Similarly, we
now have polymers that are semiconductive and, more recently, a superconductive
polymer has also been discovered.
Classification of technologically useful electronic materials.
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™
is a

By alloying multiple compounds, some semiconductor materials are tunable, e.g., in
band gap or lattice constant.
The result is ternary, quaternary, or even quinary compositions.
Band gap..
Ternary compositions allow adjusting the band gap within the range of the involved
binary compounds; however, in case of combination of direct and indirect band gap
materials there is a ratio where indirect band gap prevails, limiting the range usable
for optoelectronics; e.g. AlGaAs LEDs are limited to 660 nm by this.
Lattice constant..
Lattice constants of the compounds also tend to be different, and the lattice
mismatch against the substrate, dependent on the mixing ratio, causes defects in
amounts dependent on the mismatch magnitude; this influences the ratio of
achievable radiative/nonradiative recombinations and determines the luminous
efficiency of the device.
Band gap and lattice constant..
Quaternary and higher compositions allow adjusting simultaneously the band gap
and the lattice constant, allowing increasing radiant efficiency at wider range of
wavelengths; for example AlGaInP is used for LEDs .
Materials transparent to the generated wavelength of light are advantageous, as this
allows more efficient extraction of photons from the bulk of the material. That is, in
such transparent materials, light production is not limited to just the surface.

Silicon (Si) and Germanium (Ge)
In solid state electronics, either pure silicon or germanium may be used as the
intrinsic semiconductor which forms the starting point for fabrication. Each has four
valence electrons, but germanium will at a given temperature have more free
electrons and a higher conductivity.
Silicon is by far the more widely used semiconductor for electronics, partly because
it can be used at much higher temperatures than germanium.

Si vs GaAs
Compound semiconductors have both advantages and disadvantages.
For example, gallium arsenide (GaAs) has six times higher electron mobility than
silicon, which allows faster operation; wider band gap, which allows operation of
power devices at higher temperatures, and gives lower thermal noise to low power
devices at room temperature.
Direct band gap gives compound semiconductors more favorable optoelectronic
properties than the indirect band gap of silicon; it can be alloyed to ternary and
quaternary compositions, with adjustable band gap width, allowing light emission at
chosen wavelengths, and allowing e.g. matching to wavelengths with lowest losses
in optical fibers.
GaAs can be also grown in a semi-insulating form, which is suitable as a lattice-
matching insulating substrate for GaAs devices.
Conversely..
Silicon is robust, cheap, and easy to process.
whereas..
GaAs is brittle and expensive, and insulation layers cannot be created by just
growing an oxide layer; GaAs is therefore used only where silicon is not sufficient.

Silicon (Si) vs Silicon Carbide (SiC)
SiC devices belong to the so-called wide band gap semiconductor group,
When compared to commonly used silicon (Si), SiC offers a number of attractive
characteristics for high voltage power semiconductors.
Much higher breakdown field strength
Much higher thermal conductivity
thus allow creating devices which outperform by far the corresponding Si ones, and
enable reaching otherwise unattainable efficiency levels.

Indium Arsenide (InAs)
http://www.azom.com/article.aspx?ArticleID=8355
Description
Indium arsenide is a semiconductor material made of arsenic and indium.
The semiconductor has a melting point of 942 °C and appears in the form of grey
crystals with a cubic structure.
It is very similar to gallium arsenide and is a material having a direct bandgap.
Indium arsenide is popular for its narrow energy bandgap and high electron mobility.
Applications
The applications of indium arsenide are listed below:
• Indium arsenide is used to construct infrared detectors for a wavelength range
of 1–3.8 µm. The detectors are normally photovoltaic photodiodes.
• Detectors that are cryogenically cooled have low noise but InAs detectors can
be used in high-power applications at room temperature also.
• Diode lasers are also made using indium arsenide.
• Indium arsenide and gallium arsenide are similar and it is a direct bandgap
material.
• It is used as a terahertz radiation source.
• It is possible to form quantum dots in a monolayer of indium arsenide on
gallium arsenide or indium phosphide
• It is also possible to form quantum dots in indium gallium arsenide in the form
of indium arsenide dots arranged in the gallium arsenide matrix.

Toxicity of indium arsenide, gallium arsenide, and aluminium gallium arsenide.
Tanaka A.
Source: Department of Hygiene, Graduate School of Medical Sciences, Kyushu University, Higashi-
ku, Fukuoka 812-8582, Japan. atanaka@eisei.med.kyushu-u.ac.jp
Gallium arsenide (GaAs), indium arsenide (InAs), and aluminium gallium arsenide
(AlGaAs) are semiconductor applications. Although the increased use of these
materials has raised concerns about occupational exposure to them, there is little
information regarding the adverse health effects to workers arising from exposure to
these particles. However, available data indicate these semiconductor materials can
be toxic in animals.
Although acute and chronic toxicity of the lung, reproductive organs, and kidney are
associated with exposure to these semiconductor materials, in particular, chronic
toxicity should pay much attention owing to low solubility of these materials.
Between InAs, GaAs, and AlGaAs, InAs was the most toxic material to the lung
followed by GaAs and AlGaAs when given intra-tracheally. This was probably due to
difference in the toxicity of the counter-element of arsenic in semiconductor
materials, such as indium, gallium, or aluminium, and not arsenic itself. It appeared
that indium, gallium, or aluminium was toxic when released from the particles,
though the physical character of the particles also contributes to toxic effect.
Although there is no evidence of the carcinogenicity of InAs or AlGaAs, GaAs and
InP, which are semiconductor materials, showed the clear evidence of carcinogenic
potential. It is necessary to pay much greater attention to the human exposure of
semiconductor materials.

Directand IndirectBandgapSemiconductor
In a direct bandgap semiconductor, an electron can be promoted from the
conduction band to the valence band without changing the momentum of the
electron. An example of a direct bandgap semiconductor is GaAs. When the exited
falls back into the valence band, electrons and holes combine to produce light.
Thus, electron + hole  hν
This is known as radiative recombination. Thus, direct bandgap materials such as
GaAs and solid solutions of these (e.g. GaAs-AlAs) are used to make light-emitting
diodes (LEDs) of different colours. The bandgap of semiconductors can be tuned
using solid solutions. The change in bandgap produces a change in the wavelength
(i.e. the frequency of the colour (ν) is related to the bandgap Eg as Eg = hν, where h is
the Plank’s constant). Since an optical effect is obtained using an electronic material,
often the direct bandgap materials are known as optoelectronic materials. Many
lasers and LEDs have been developed using these materials. LEDs that emit light in
the infrared range are used in optical-fiber communication systems to convert light
waves into electrical pulses. Different coloured lasers, such as the newest blue laser
using GaN, have been developed using direct bandgap materials.
In an indirect bandgap semiconductor (e.g. Si, Ge, GaP) the electron-hole
recombination is very efficient and the electrons cannot be promoted to the valence
band without a change in momentum. As a result, in materials that have an indirect
bandgap, we cannot get light emission. Instead, electrons and holes combine to
produce heat that is dissipated within the material. Thus, electron + hole  heat.
This is known as non-radiative recombination.
Note that both direct and indirect bandgap materials can be doped to form n-type or
p-type semiconductors.

OLED
Organic light-emitting diodes (OLEDs) could revolutionize the market for displays.
OLEDs are..
self-luminous
rich in contrast
extremely flat
video-capable
Numerous manufacturers have now introduced their own brands for OLED products,
including Osram Opto Semiconductors. Osram Opto Semiconductors is currently
producing only passivematrix displays made of polymers.
Two types of organic chemicals emit light when a voltage is applied to them: long-
chain polymers and small molecules. Furthermore, two underlying phenomena are
involved: fluorescence and phosphorescence. And in the field of display technology,
there are two contrasting architectures: active-matrix and passive-matrix. Here, the
anode and cathode consist of narrow conductor paths that cross at 90 degrees and
enclose the polymer layer (see graphic). The points at which these electrodes
intersect form pixels. Light is radiated outward through a transparent electrode made
of indium tin oxide. Passive-matrix displays are relatively easy to manufacture, but
because of losses in their electrical conductors, they are limited in size to screen
diagonals of about five centimeters. This limitation is absent in active-matrix displays,
which are more complex. Here, each pixel is individually activated, which requires an
integrated circuit at the display level. The ideal solution would be thin-film transistors
made of polycrystalline silicon, but they are not yet widely available. If integrated
circuits use competing amorphous silicon technology, however, power consumption
is too high.
In a passive-matrix display the cathode and anode form a square grid. Pixels made
of OLED material are excited by an electrical current, causing them to emit light.

Organic Light Emitting Diode (OLED)
OLED (Organic Light Emitting Diodes) is a flat light emitting technology, made by
placing a series of organic thin films between two conductors. When electrical
current is applied, a bright light is emitted. OLEDs can be used to make displays and
lighting. Because OLEDs emit light they do not require a backlight and so are thinner
and more efficient than LCD displays (which do require a white backlight).

OLED vs LCD
OLED displays have the following advantages over LCD displays;
 Lower power consumption
 Faster refresh rate and better contrast
 Greater brightness - The screens are brighter, and have a fuller
viewing angle
 Exciting displays - new types of displays, that we do not have today,
like ultra-thin, flexible or transparent displays
 Better durability - OLEDs are very durable and can operate in a
broader temperature range
 Lighter weight - the screen can be made very thin, and can even be
'printed' on flexible surfaces
Flexible and transparent OLED displays
It turns out that because OLEDs are thin and simple - they can be used to create
flexible and even transparent displays.
This is pretty exciting as it opens up a whole world of possibilities:
 Curved OLED displays, placed on non-flat surfaces
 Wearable OLEDs
 Transparent OLEDs embedded in windows
 OLEDs in car windshields
 New designs for lamps
 And many more we cannot even imagine today...
 OLED video
https://www.youtube.com/watch?v=QqyW9vdS0x0
*Video (@youtube)
-Bendable smartphone
http://ceramics.org/ceramic-tech-today/video-new-smartphone-prototype-bends-to-
meet-consumers-needs
-the verge

Quantum dot
A quantum dot is a semiconductor nanostructure that confines the motion of
conduction band electrons, valence band holes, or excitons (bound pairs of
conduction band electrons and valence band holes) in all three spatial directions.
The confinement can be due to..
- electrostatic potentials (generated by external electrodes, doping, strain,
impurities)
- the presence of an interface between different semiconductor materials
(e.g. in core-shell nanocrystal systems)
- the presence of the semiconductor surface (e.g. semiconductor
nanocrystal)
- ..or a combination of these.
A quantum dot has a discrete quantized energy spectrum.
The corresponding wave functions are spatially localized within the quantum dot, but
extend over many periods of the crystal lattice.
A quantum dot contains a small finite number (of the order of 1-100) of conduction
band electrons, valence band holes, or excitons, i.e., a finite number of elementary
electric charges.
Small quantum dots, such as colloidal semiconductor nanocrystals, can be as small
as 2 to 10 nm, corresponding to 10 to 50 atoms in diameter and a total of 100 to
100,000 atoms within the quantum dot volume. Self-assembled quantum dots are
typically between 10 and 50 nm in size.
Quantum dots defined by lithographically patterned gate electrodes, or by etching on
two-dimensional electron gases in semiconductor heterostructures can have lateral
dimensions exceeding 100 nm.
At 10 nm in diameter, nearly 3 million quantum dots could be lined up end to end and
fit within the width of a human thumb.

Note: The above text is excerpted from the Wikipedia article "Quantum dot", which has been
released under theGNU Free Documentation License.
Online source :-
- Quantum dot slides - http://www.slideshare.net/mcleang1/quantum-dots
Quantum dots article :-
http://nanotechweb.org/cws/article/yournews/37550
http://nanotechweb.org/cws/article/tech/47653

Silicon Carbide Schottky Diodes
The differences in material properties between SiC and silicon limit the fabrication of
practical silicon unipolar diodes (Schottky diodes) to a range up to 100V – 150V, with
relatively high on-state resistance and leakage current. On the other hand, SiC
Schottky barrier diodes (SBD) can reach a much higher breakdown voltage; Infineon
offers products up to 1200V as discrete and up to 1700V in modules.
• Applications
• Server
• Telecom
• Solar
• UPS
• PC Silverbox
• Motor Drives
• Lighting
Features Benefits
• Benchmark switching behavior
• No reverse recovery charge
• Temperature independent
switching behavior
• High operating temperature (T j
max 175°C)
• System efficiency improvement
compared to Si diodes
• Reduced cooling requirements
• Enabling higher
frequency/increased power
density
• Higher system reliability due to
lower operating temperature
• Reduced EMI

• Diodes
Diodes
• pn homojunctions
• Heterojunctions
• Metal-semiconductorjunctions
Diodes
• Metal-Oxide-Semiconductor
FET (MOSFET)
• JunctionFET (JFET)
Field-effect
transistors
• HeterojunctionBipolar
Transistors
Bipolar
junction
transistors
• Solar cells
• Photodetectors
• Photoluminescence
• Electroluminescence
• Light-emitting diodes
• Laser diodes
• Image sensors
Optoelectronic
Devices

• Tunneldiode
• Gunn diode
• Impatt diode
• Power bipolartransistor
• Power MOSFET
• Thyristor
Microwave
and Power
Devices

NANOTECHNOLOGY
Nanomaterials are defined as materials with at least one external dimension in the
size range from approximately 1-100 nanometers.
Nanoparticles are objects with all three external dimensions at the nanoscale.
Nanotechnology encompasses the understanding of the fundamental physics,
chemistry, biology and technology of nanometre-scale objects.
Nanoparticles can either be..
- the naturally occurring
(e.g., volcanic ash, soot from forest fires)
- the incidental byproducts of combustion processes
(e.g., welding, diesel engines)
- are usually physically and chemically heterogeneous and often termed
ultrafine particles.
Engineered nanoparticles
- are intentionally produced and designed with very specific properties related
to shape, size, surface properties and chemistry.
- These properties are reflected in aerosols, colloids, or powders.
- Often, the behavior of nanomaterials may depend more on surface area than
particle composition itself.
- Relative-surface area is one of the principal factors that enhance its reactivity,
strength and electrical properties.
Engineered nanoparticles may be bought from commercial vendors or generated via
experimental procedures by researchers in the laboratory.
(e.g., CNTs can be produced by laser ablation, HiPCO (high-pressure carbon
monoxide, arc discharge, and chemical vapor deposition (CVD)).

Examples of engineered nanomaterials include..
carbon buckeyballs or fullerenes; carbon nanotubes; metal or metal oxide
nanoparticles (e.g., gold, titanium dioxide); quantum dots, among many others.
Research in the microelectronics and nanotechnology area includes topics such
as..
- Fabrication of new electronic materials and devices.
- Computational studies of electronic devices.
Research in nanotechnology in other field of studies include..
Biology
Medicine
Environment
Energy
Electronics -Patterning and Fabrication
Photonics
Sensors
Material Synthesis
Material Properties and Characterization
Topics regarding nanotechnology may cover..
New materials fabrications
New products applications
Materials Characterization
Cleanrooms
Health Issues
CNT
OLED
Quantum Dots
MEMS
Solar Cells

(from article)
Nanotechnology: Health issues
Approaches to Safe Nanotechnology: Managing the Health and Safety
Concerns Associated with Engineered Nanomaterials
This document reviews what is currently known about nanoparticle toxicity,
process emissions and exposure assessment, engineering controls, and
personal protective equipment.
This updated version of the document incorporates some of the latest results of
NIOSH research, but it is only a starting point. The document serves a dual purpose:
it is a summary of NIOSH's current thinking and interim recommendations; and it is a
request from NIOSH to occupational safety and health practitioners, researchers,
product innovators and manufacturers, employers, workers, interest group
members, and the general public to exchange information that will ensure that no
worker suffers material impairment of safety or health as nanotechnology develops.
Potential Health Concerns
The potential for nanomaterials to enter the body is among several factors that
scientists examine in determining whether such materials may pose an occupational
health hazard. Nanomaterials have the greatest potential to enter the body through
the respiratory system if they are airborne and in the form of respirable-sized
particles (nanoparticles). They may also come into contact with the skin or be
ingested.
Based on results from human and animal studies, airborne nanoparticles can be
inhaled and deposit in the respiratory tract; and based on animal studies,
nanoparticles can enter the blood stream, and translocate to other organs.
Experimental studies in rats have shown that equivalent mass doses of insoluble
incidental nanoparticles are more potent than large particles of similar composition in

causing pulmonary inflammation and lung tumors. Results from in vitro cell culture
studies with similar materials are generally supportive of the biological responses
observed in animals.
Experimental studies in animals, cell cultures, and cell-free systems have shown that
changes in the chemical composition, crystal structure, and size of particles can
influence their oxidant generation properties and cytotoxicity.
Studies in workers exposed to aerosols of some manufactured or incidental
microscopic (fine) and nanoscale (ultrafine) particles have reported adverse lung
effects including lung function decrements and obstructive and fibrotic lung diseases.
The implications of these studies to engineered nanoparticles, which may have
different particle properties, are uncertain.
Research is needed to determine the key physical and chemical characteristics of
nanoparticles that determine their hazard potential.
Potential Safety Concerns
Although insufficient information exists to predict the fire and explosion risk
associated with powders of nanomaterials, nanoscale combustible material could
present a higher risk than coarser material with a similar mass concentration given
its increased particle surface area and potentially unique properties due to the
nanoscale.
Some nanomaterials may initiate catalytic reactions depending on their composition
and structure that would not otherwise be anticipated based on their chemical
composition.

Working with Engineered Nanomaterials
Nanomaterial-enabled products such as nanocomposites, surface-coated materials,
and materials comprised of nanostructures, such as integrated circuits, are unlikely
to pose a risk of exposure during their handling and use as materials of non-
inhalable size. However, some of the processes used in their production (e.g.,
formulating and applying nanoscale coatings) may lead to exposure to
nanomaterials, and the cutting or grinding of such products could release respirable-
sized nanoparticles.
Maintenance on production systems (including cleaning and disposal of materials
from dust collection systems) is likely to result in exposure to nanoparticles if
deposited nanomaterials are disturbed.
The following workplace tasks can increase the risk of exposure to nanoparticles:
 Working with nanomaterials in liquid media without adequate protection. (e.g.,
gloves)
 Working with nanomaterials in liquid during pouring or mixing operations, or
where a high degree of agitation is involved.
 Generating nanoparticles in non-enclosed systems.
 Handling (e.g., weighing, blending, spraying) powders of nanomaterials.
 Maintenance on equipment and processes used to produce or fabricate
nanomaterials and the cleaning-up of spills and waste material containing
nanomaterials.
 Cleaning of dust collection systems used to capture nanoparticles.
 Machining, sanding, drilling, or other mechanical disruptions of materials
containing nanoparticles.

(from website)
MEMSTechnology
https://www.mems-exchange.org/MEMS/what-is.html
What is MEMS Technology?
Micro-Electro-Mechanical Systems, or MEMS, is a technology that in its most
general form can be defined as miniaturized mechanical and electro-mechanical
elements (i.e., devices and structures) that are made using the techniques of
microfabrication.
The critical physical dimensions of MEMS devices can vary from well below one
micron on the lower end of the dimensional spectrum, all the way to several
millimeters.
Likewise, the types of MEMS devices can vary from relatively simple structures
having no moving elements, to extremely complex electromechanical systems
with multiple moving elements under the control of integrated microelectronics.
The one main criterion of MEMS is that there are at least some elements having
some sort of mechanical functionality whether or not these elements can move.
The term used to define MEMS varies in different parts of the world. In the United
States they are predominantly called MEMS, while in some other parts of the world
they are called “Microsystems Technology” or “micromachined devices”.
While the functional elements of MEMS are miniaturized structures, sensors,
actuators, and microelectronics, the most notable (and perhaps most interesting)
elements are the microsensors and microactuators. Microsensors and
microactuators are appropriately categorized as “transducers”, which are defined as
devices that convert energy from one form to another. In the case of microsensors,
the device typically converts a measured mechanical signal into an electrical signal.

Over the past several decades MEMS researchers and developers have
demonstrated an extremely large number of microsensors for almost every possible
sensing modality including temperature, pressure, inertial forces, chemical species,
magnetic fields, radiation, etc. Remarkably, many of these micromachined sensors
have demonstrated performances exceeding those of their macroscale counterparts.
That is, the micromachined version of, for example, a pressure transducer, usually
outperforms a pressure sensor made using the most precise macroscale level
machining techniques. Not only is the performance of MEMS devices exceptional,
but their method of production leverages the same batch fabrication techniques used
in the integrated circuit industry – which can translate into low per-device production
costs, as well as many other benefits. Consequently, it is possible to not only
achieve stellar device performance, but to do so at a relatively low cost level. Not
surprisingly, silicon based discrete microsensors were quickly commercially exploited
and the markets for these devices continue to grow at a rapid rate.
More recently, the MEMS research and development community has demonstrated
a number of microactuators including: microvalves for control of gas and liquid flows;
optical switches and mirrors to redirect or modulate light beams; independently
controlled micromirror arrays for displays, microresonators for a number of different
applications, micropumps to develop positive fluid pressures, microflaps to modulate
airstreams on airfoils, as well as many others. Surprisingly, even though these
microactuators are extremely small, they frequently can cause effects at the
macroscale level; that is, these tiny actuators can perform mechanical feats far larger
than their size would imply. For example, researchers have placed small

microactuators on the leading edge of airfoils of an aircraft and have been able to
steer the aircraft using only these microminiaturized devices.
A surface micromachined electro-statically-actuated micromotor fabricated by the MNX. This
device is an example of a MEMS-based microactuator.
The real potential of MEMS starts to become fulfilled when these miniaturized
sensors, actuators, and structures can all be merged onto a common silicon
substrate along with integrated circuits (i.e., microelectronics). While the electronics
are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar,
or BICMOS processes), the micromechanical components are fabricated using
compatible "micromachining" processes that selectively etch away parts of the
silicon wafer or add new structural layers to form the mechanical and
electromechanical devices. It is even more interesting if MEMS can be merged not
only with microelectronics, but with other technologies such as photonics,
nanotechnology, etc. This is sometimes called “heterogeneous integration.” Clearly,
these technologies are filled with numerous commercial market opportunities.
While more complex levels of integration are the future trend of MEMS technology,
the present state-of-the-art is more modest and usually involves a single discrete
microsensor, a single discrete microactuator, a single microsensor integrated with
electronics, a multiplicity of essentially identical microsensors integrated with
electronics, a single microactuator integrated with electronics, or a multiplicity of
essentially identical microactuators integrated with electronics. Nevertheless, as

MEMS fabrication methods advance, the promise is an enormous design freedom
wherein any type of microsensor and any type of microactuator can be merged with
microelectronics as well as photonics, nanotechnology, etc., onto a single substrate.
A surface micromachined resonator fabricated by the MNX. This device can be used as both
a microsensor as well as a microactuator.
This vision of MEMS whereby microsensors, microactuators and microelectronics
and other technologies, can be integrated onto a single microchip is expected to be
one of the most important technological breakthroughs of the future. This will enable
the development of smart products by augmenting the computational ability of
microelectronics with the perception and control capabilities of microsensors and
microactuators. Microelectronic integrated circuits can be thought of as the "brains"
of a system and MEMS augments this decision-making capability with "eyes" and
"arms", to allow microsystems to sense and control the environment. Sensors gather
information from the environment through measuring mechanical, thermal, biological,
chemical, optical, and magnetic phenomena. The electronics then process the
information derived from the sensors and through some decision making capability
direct the actuators to respond by moving, positioning, regulating, pumping, and
filtering, thereby controlling the environment for some desired outcome or purpose.
Furthermore, because MEMS devices are manufactured using batch fabrication
techniques, similar to ICs, unprecedented levels of functionality, reliability, and
sophistication can be placed on a small silicon chip at a relatively low cost. MEMS
technology is extremely diverse and fertile, both in its expected application areas, as

well as in how the devices are designed and manufactured. Already, MEMS is
revolutionizing many product categories by enabling complete systems-on-a-chip to
be realized.
Nanotechnology is the ability to manipulate matter at the atomic or molecular level to
make something useful at the nano-dimensional scale. Basically, there are two
approaches in implementation: the top-down and the bottom-up. In the top-down
approach, devices and structures are made using many of the same techniques as
used in MEMS except they are made smaller in size, usually by employing more
advanced photolithography and etching methods. The bottom-up approach typically
involves deposition, growing, or self-assembly technologies. The advantages of
nano-dimensional devices over MEMS involve benefits mostly derived from the
scaling laws, which can also present some challenges as well.
An array of sub-micron posts made using top-down nanotechnology fabrication methods.
Some experts believe that nanotechnology promises to:
a). allow us to put essentially every atom or molecule in the place and position
desired – that is, exact positional control for assembly,
b). allow us to make almost any structure or material consistent with the laws of
physics that can be specified at the atomic or molecular level; and
c). allow us to have manufacturing costs not greatly exceeding the cost of the
required raw materials and energy used in fabrication (i.e., massive
parallelism).
Although MEMS and Nanotechnology are sometimes cited as separate and distinct
technologies, in reality the distinction between the two is not so clear-cut. In fact,
these two technologies are highly dependent on one another.

The well-known scanning tunneling-tip microscope (STM) which is used to detect
individual atoms and molecules on the nanometer scale is a MEMS device.
A colorized image of a scanning-tunneling microscope image of a surface, which is a
common imaging technique used in nanotechnology.
Similarly the atomic force microscope (AFM) which is used to manipulate the
placement and position of individual atoms and molecules on the surface of a
substrate is a MEMS device as well. In fact, a variety of MEMS technologies are
required in order to interface with the nano-scale domain.
Likewise, many MEMS technologies are becoming dependent on nanotechnologies
for successful new products. For example, the crash airbag accelerometers that are
manufactured using MEMS technology can have their long-term reliability degraded
due to dynamic in-use stiction effects between the proof mass and the substrate. A
nanotechnology called Self-Assembled Monolayers (SAM) coatings are now
routinely used to treat the surfaces of the moving MEMS elements so as to prevent
stiction effects from occurring over the product’s life.
Many experts have concluded that MEMS and nanotechnology are two different
labels for what is essentially a technology encompassing highly miniaturized things
that cannot be seen with the human eye. Note that a similar broad definition exists in
the integrated circuits domain which is frequently referred to as microelectronics
technology even though state-of-the-art IC technologies typically have devices with
dimensions of tens of nanometers. Whether or not MEMS and nanotechnology are
one in the same, it is unquestioned that there are overwhelming mutual
dependencies between these two technologies that will only increase in time.
Perhaps what is most important are the common benefits afforded by these

technologies, including: increased information capabilities; miniaturization of
systems; new materials resulting from new science at miniature dimensional scales;
and increased functionality and autonomy for systems.

Cleanroom
(from website)
Cleanroom http://www.advancetecllc.com/nanotechnology_microelectronics.html
Whether you require a 1,000 square foot Class 100 cleanroom or a fully functional volume
production fab, AdvanceTEC can address your critical requirements for contamination
control, code compliance, and process tool fit-up & installation.
Our Approach
AdvanceTEC provides comprehensive cleanroom design and cleanroom construction
capabilities to serve Nanotech and Semiconductor clients. We understand the technical
challenges of these facilities, and deploy the capabilities required to ensure your success.
Requirements
Gathering
Design and Engineering
Construction
Management
 Process utility studies
 Code compliance
evaluations
 Chemical and gas storage
and distribution plans
 HVAC, mechanical and
exhaust systems
 Estimating, budgeting and
schedule development
 Process tool infrastructure
and services integration
 Conceptual design,
programming and layout
 Design for constructability
and maintainability
 Budget creation and
schedule optimization
 Experienced, salaried
Project and Construction
Management
 Clean Build Protocol
construction
 Commissioning,
certification and training
 Process tool fit-up and
hook-up
 Site safety
Our Experience
AdvanceTEC has a proven track record of addressing diverse mechanical, architectural and
process utility requirements of leading edge Nanotech and Semiconductor cleanrooms.
Applications
Design Approach Facility Types
 Bay & chase vs. ballroom
 Fan Filter Unit (FFU) vs. Terminal HEPA
 Plenum module, flush grid, rod hung T-
grid ceilings
 Raised access floors vs. other flooring
systems
 RO/DI water systems
 HPM evaluation, design and management
 R&D applications labs
 Trace metals cleanrooms
 Pilot lines
 High volume wafer fabs
 Test floors and final packaging
 MOCVD labs
 TEM/SEM rooms
 Quiet Labs

Design Approach Facility Types
 Scrubbed exhaust systems
 Toxic gas monitoring and life safety
 Subfabs, chemical bunkers and distribution
centersy
 Radiant Cooled Labs
Cleanliness Classifications
Federal Standard 209e
more information
ISO Standard 14446
more information
Class 10
Class 100
Class 1,000
Class 10,000
Class 100,000
ISO 4
ISO 5
ISO 6
ISO 7
ISO 8

(from article)
Nanotechnology(CNT)in Civil/StructuralEngineering
Nanoscience and nanotechnology provide enormous opportunities to engineers the
properties of materials by working in atomic or molecular level.
It has not only facilitated to overcome many limitations of conventional
materials, but also tremendously improved the mechanical, physical and
chemical properties of the materials as well.
To develop high performance, multifunctional, ideal (high strength, ductile,
crack free, durable) construction material, carbon nanotubes (CNTs) show
promising role to modify/enhance the characteristics of the conventional
construction materials such as concrete and steel.
In the paper, a brief on geometry and mechanical properties, synthesis processes,
possibilities and findings of different researchers on CNT reinforced composites is
presented. It is also brought out that a crack free durable concrete is possible if
certain issues such as uniform distribution of CNT in composite and bond behavior of
CNT modified concrete can be addressed. Finally, few pre-proof of concepts are
mentioned where CNTs can play the pivotal role to redefine the scope and ability of
civil engineering, in general, and structural engineering, in particular.
Nanoscience has paved the way to tailor the properties of materials based on
particular requirement by working in atomic or molecular level. In general,
nanotechnology is not an isolated technology for certain purposes, but it is an
enabling technology to achieve many goals by engineering a material at nano level.
Similar to the fields like energy, medicine, electronics, etc., nanotechnology shows
remarkable potentiality of its role to play by opening a new way to solve many of the
perennial problems civil engineers do face every day. Aggressive development of
infrastructures using conventional constructional materials will be responsible for
approx. one-third of global warming. It is estimated that per ton production of cement
approximately produces one ton of CO2. Hence, there is an alarming need for
developing new construction material which is smart, efficient and sustainable. The

countries like India, where growth of infrastructure plays a significant role in the
growth of the country, engineering of green and smart construction material will
enormously help to generate public, private, strategic and societal goods. Among all
the nano forms of metals and non-metals, carbon nanotubes (CNTs) seem to have
the most promising role towards developing an ideal (high strength, ductile, crack
free, durable) construction material like concrete. The carbon nanotubes (CNTs)
attract the researchers since their discovery, because of their higher strength and
relatively low weight. These nanotubes are useful for any application where
robustness and flexibility are necessary. Further, nanotubes are also stable under
extreme chemical environments, high temperatures and moisture as well. Use of
nano engineered concrete would lead to considerable reduction in the dimensions of
the structural members which could result in much less consumption of cement and
thereby reduction of CO2 release and make the world sustainable through eco-
friendly products. Further, carbon nanotubes can also be used to make nano
composite steel. Initial research findings reveal that they are about 50 times stronger
and 10 times lighter than conventional steel. Apart from technical intricacies and lack
of information, one of the main obstacles in using CNTs in construction is cost of
CNTs as construction materials need to be produced in mass and should be
reasonably cheap. Exorbitant cost implications in production of CNTs are diminishing
very fast. For example, cost of industrial CNT was $27,000/lb in 1992, $550/lb in
2006 and $120/lb in 2011. It is also predicted that the price would be as low as
$0.5/lb in 201314 [1]. To bring out the best from carbon nanotubes to the
construction industry, specifically, in usage of construction materials, the
extraordinary geometrical shape, unparallel mechanical properties, complex but
challenging synthesis processes, and probable areas of applications are essential to
be known. Therefore, an overview of these aspects of carbon nanotubes with the
current state of knowledge is brought out in the present paper.

Semiconductor Materials for Electronics

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