<s>
Nanocircuits	B-Algorithm
are	O
electrical	O
circuits	O
operating	O
on	O
the	O
nanometer	O
scale	O
.	O
</s>
<s>
Nanocircuits	B-Algorithm
are	O
composed	O
of	O
three	O
different	O
fundamental	O
components	O
.	O
</s>
<s>
These	O
are	O
transistors	B-Application
,	O
interconnections	O
,	O
and	O
architecture	B-General_Concept
,	O
all	O
fabricated	O
on	O
the	O
nanometer	O
scale	O
.	O
</s>
<s>
A	O
variety	O
of	O
proposals	O
have	O
been	O
made	O
to	O
implement	O
nanocircuitry	B-Algorithm
in	O
different	O
forms	O
.	O
</s>
<s>
These	O
include	O
Nanowires	B-Architecture
,	O
Single-Electron	O
Transistors	B-Application
,	O
Quantum	O
dot	O
cellular	O
automata	O
,	O
and	O
Nanoscale	O
Crossbar	O
Latches	O
.	O
</s>
<s>
However	O
,	O
likely	O
nearer-term	O
approaches	O
will	O
involve	O
incorporation	O
of	O
nanomaterials	O
to	O
improve	O
MOSFETs	B-Architecture
(	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
field-effect	I-Architecture
transistors	I-Architecture
)	O
.	O
</s>
<s>
A	O
review	O
article	O
covering	O
the	O
MOSFET	B-Architecture
design	O
and	O
its	O
future	O
was	O
published	O
in	O
2004	O
comparing	O
different	O
geometries	O
of	O
MOSFETs	B-Architecture
under	O
scale	O
reduction	O
and	O
noted	O
that	O
circular	O
cross-section	O
vertical	O
channel	O
FETs	O
are	O
optimal	O
for	O
scale	O
reduction	O
.	O
</s>
<s>
This	O
configuration	O
is	O
capable	O
of	O
being	O
implemented	O
with	O
a	O
high	O
density	O
using	O
vertical	O
semiconductor	O
cylindrical	O
channels	O
with	O
nanoscale	O
diameters	O
and	O
Infineon	O
Technologies	O
and	O
Samsung	B-Application
have	O
begun	O
research	O
and	O
development	O
in	O
this	O
direction	O
resulting	O
in	O
some	O
basic	O
patents	O
using	O
nanowires	B-Architecture
and	O
carbon	O
nanotubes	O
in	O
MOSFET	B-Architecture
designs	O
.	O
</s>
<s>
In	O
an	O
alternative	O
approach	O
,	O
Nanosys	O
uses	O
solution	O
based	O
deposition	O
and	O
alignment	O
processes	O
to	O
pattern	O
pre-fabricated	O
arrays	O
of	O
nanowires	B-Architecture
on	O
a	O
substrate	O
to	O
serve	O
as	O
a	O
lateral	O
channel	O
of	O
an	O
FET	O
.	O
</s>
<s>
While	O
not	O
capable	O
of	O
the	O
same	O
scalability	O
as	O
single	O
nanowire	B-Architecture
FETs	O
,	O
the	O
use	O
of	O
pre-fabricated	O
multiple	O
nanowires	B-Architecture
for	O
the	O
channel	O
increases	O
reliability	O
and	O
reduces	O
production	O
costs	O
since	O
large	O
volume	O
printing	O
processes	O
may	O
be	O
used	O
to	O
deposit	O
the	O
nanowires	B-Architecture
at	O
a	O
lower	O
temperature	O
than	O
conventional	O
fabrication	O
procedures	O
.	O
</s>
<s>
In	O
addition	O
,	O
due	O
to	O
the	O
lower	O
temperature	O
deposition	O
a	O
wider	O
variety	O
of	O
materials	O
such	O
as	O
polymers	O
may	O
be	O
used	O
as	O
the	O
carrier	O
substrate	O
for	O
the	O
transistors	B-Application
opening	O
the	O
door	O
to	O
flexible	O
electronic	O
applications	O
such	O
as	O
electronic	O
paper	O
,	O
bendable	O
flat	O
panel	O
displays	O
,	O
and	O
wide	O
area	O
solar	O
cells	O
.	O
</s>
<s>
One	O
of	O
the	O
most	O
fundamental	O
concepts	O
to	O
understanding	O
nanocircuits	B-Algorithm
is	O
the	O
formulation	O
of	O
Moore	O
’s	O
Law	O
.	O
</s>
<s>
This	O
concept	O
arose	O
when	O
Intel	O
co-founder	O
Gordon	O
Moore	O
became	O
interested	O
in	O
the	O
cost	O
of	O
transistors	B-Application
and	O
trying	O
to	O
fit	O
more	O
onto	O
one	O
chip	O
.	O
</s>
<s>
It	O
relates	O
that	O
the	O
number	O
of	O
transistors	B-Application
that	O
can	O
be	O
fabricated	O
on	O
a	O
silicon	O
integrated	O
circuit	O
—	O
and	O
therefore	O
the	O
computing	O
abilities	O
of	O
such	O
a	O
circuit	O
—	O
is	O
doubling	O
every	O
18	O
to	O
24	O
months	O
.	O
</s>
<s>
The	O
more	O
transistors	B-Application
one	O
can	O
fit	O
on	O
a	O
circuit	O
,	O
the	O
more	O
computational	O
abilities	O
the	O
computer	O
will	O
have	O
.	O
</s>
<s>
This	O
is	O
why	O
scientists	O
and	O
engineers	O
are	O
working	O
together	O
to	O
produce	O
these	O
nanocircuits	B-Algorithm
so	O
increasingly	O
more	O
and	O
more	O
transistors	B-Application
will	O
be	O
able	O
to	O
fit	O
onto	O
a	O
chip	O
.	O
</s>
<s>
Despite	O
how	O
good	O
this	O
may	O
sound	O
,	O
there	O
are	O
many	O
problems	O
that	O
arise	O
when	O
so	O
many	O
transistors	B-Application
are	O
packed	O
together	O
.	O
</s>
<s>
As	O
more	O
transistors	B-Application
are	O
packed	O
onto	O
a	O
chip	O
,	O
phenomena	O
such	O
as	O
stray	O
signals	O
on	O
the	O
chip	O
,	O
the	O
need	O
to	O
dissipate	O
the	O
heat	O
from	O
so	O
many	O
closely	O
packed	O
devices	O
,	O
tunneling	O
across	O
insulation	O
barriers	O
due	O
to	O
the	O
small	O
scale	O
,	O
and	O
fabrication	O
difficulties	O
will	O
halt	O
or	O
severely	O
slow	O
progress	O
.	O
</s>
<s>
In	O
producing	O
these	O
nanocircuits	B-Algorithm
,	O
there	O
are	O
many	O
aspects	O
involved	O
.	O
</s>
<s>
The	O
first	O
part	O
of	O
their	O
organization	O
begins	O
with	O
transistors	B-Application
.	O
</s>
<s>
As	O
of	O
right	O
now	O
,	O
most	O
electronics	O
are	O
using	O
silicon-based	O
transistors	B-Application
.	O
</s>
<s>
Transistors	B-Application
are	O
an	O
integral	O
part	O
of	O
circuits	O
as	O
they	O
control	O
the	O
flow	O
of	O
electricity	O
and	O
transform	O
weak	O
electrical	O
signals	O
to	O
strong	O
ones	O
.	O
</s>
<s>
Circuits	O
now	O
use	O
silicon	O
as	O
a	O
transistor	B-Application
because	O
it	O
can	O
easily	O
be	O
switched	O
between	O
conducting	O
and	O
nonconducting	O
states	O
.	O
</s>
<s>
However	O
,	O
in	O
nanoelectronics	B-Algorithm
,	O
transistors	B-Application
might	O
be	O
organic	O
molecules	O
or	O
nanoscale	O
inorganic	O
structures	O
.	O
</s>
<s>
Semiconductors	O
,	O
which	O
are	O
part	O
of	O
transistors	B-Application
,	O
are	O
also	O
being	O
made	O
of	O
organic	O
molecules	O
in	O
the	O
nano	O
state	O
.	O
</s>
<s>
This	O
involves	O
logical	O
and	O
mathematical	O
operations	O
and	O
the	O
wires	O
linking	O
the	O
transistors	B-Application
together	O
that	O
make	O
this	O
possible	O
.	O
</s>
<s>
In	O
nanocircuits	B-Algorithm
,	O
nanotubes	O
and	O
other	O
wires	O
as	O
narrow	O
as	O
one	O
nanometer	O
are	O
used	O
to	O
link	O
transistors	B-Application
together	O
.	O
</s>
<s>
Nanowires	B-Architecture
have	O
been	O
made	O
from	O
carbon	O
nanotubes	O
for	O
a	O
few	O
years	O
.	O
</s>
<s>
Until	O
a	O
few	O
years	O
ago	O
,	O
transistors	B-Application
and	O
nanowires	B-Architecture
were	O
put	O
together	O
to	O
produce	O
the	O
circuit	O
.	O
</s>
<s>
However	O
,	O
scientists	O
have	O
been	O
able	O
to	O
produce	O
a	O
nanowire	B-Architecture
with	O
transistors	B-Application
in	O
it	O
.	O
</s>
<s>
In	O
2004	O
,	O
Harvard	O
University	O
nanotech	O
pioneer	O
Charles	O
Lieber	O
and	O
his	O
team	O
have	O
made	O
a	O
nanowire	B-Architecture
—	O
10,000	O
times	O
thinner	O
than	O
a	O
sheet	O
of	O
paper	O
—	O
that	O
contains	O
a	O
string	O
of	O
transistors	B-Application
.	O
</s>
<s>
Essentially	O
,	O
transistors	B-Application
and	O
nanowires	B-Architecture
are	O
already	O
pre-wired	O
so	O
as	O
to	O
eliminate	O
the	O
difficult	O
task	O
of	O
trying	O
to	O
connect	O
transistors	B-Application
together	O
with	O
nanowires	B-Architecture
.	O
</s>
<s>
The	O
last	O
part	O
of	O
nanocircuit	O
organization	O
is	O
architecture	B-General_Concept
.	O
</s>
<s>
This	O
has	O
been	O
explained	O
as	O
the	O
overall	O
way	O
the	O
transistors	B-Application
are	O
interconnected	O
,	O
so	O
that	O
the	O
circuit	O
can	O
plug	O
into	O
a	O
computer	O
or	O
other	O
system	O
and	O
operate	O
independently	O
of	O
the	O
lower-level	O
details	O
.	O
</s>
<s>
With	O
nanocircuits	B-Algorithm
being	O
so	O
small	O
,	O
they	O
are	O
destined	O
for	O
error	O
and	O
defects	O
.	O
</s>
<s>
Their	O
architecture	B-General_Concept
combines	O
circuits	O
that	O
have	O
redundant	O
logic	O
gates	O
and	O
interconnections	O
with	O
the	O
ability	O
to	O
reconfigure	O
structures	O
at	O
several	O
levels	O
on	O
a	O
chip	O
.	O
</s>
<s>
In	O
1987	O
,	O
an	O
IBM	O
research	O
team	O
led	O
by	O
Bijan	O
Davari	O
demonstrated	O
a	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
field-effect	I-Architecture
transistor	I-Architecture
(	O
MOSFET	B-Architecture
)	O
with	O
a	O
10	O
nm	O
gate	O
oxide	O
thickness	O
,	O
using	O
tungsten-gate	O
technology	O
.	O
</s>
<s>
Multi-gate	B-Algorithm
MOSFETs	I-Algorithm
enabled	O
scaling	O
below	O
20	O
nm	O
gate	O
length	O
,	O
starting	O
with	O
the	O
FinFET	O
(	O
fin	O
field-effect	O
transistor	B-Application
)	O
,	O
a	O
three-dimensional	O
,	O
non-planar	O
,	O
double-gate	B-Algorithm
MOSFET	B-Architecture
.	O
</s>
<s>
In	O
2002	O
,	O
a	O
team	O
including	O
Yu	O
,	O
Chang	O
,	O
Ahmed	O
,	O
Hu	O
,	O
Liu	O
,	O
Bokor	O
and	O
Tabery	O
fabricated	O
a	O
10nm	B-Algorithm
FinFET	O
device	O
.	O
</s>
<s>
In	O
2005	O
,	O
Indian	O
physicists	O
Prabhakar	O
Bandaru	O
and	O
Apparao	O
M	O
.	O
Rao	O
at	O
UC	O
San	O
Diego	O
developed	O
the	O
world	O
's	O
smallest	O
transistor	B-Application
based	O
to	O
be	O
made	O
entirely	O
from	O
carbon	O
nanotubes	O
.	O
</s>
<s>
It	O
was	O
intended	O
to	O
be	O
used	O
for	O
nanocircuits	B-Algorithm
.	O
</s>
<s>
In	O
2006	O
,	O
a	O
team	O
of	O
Korean	O
researchers	O
from	O
the	O
Korea	O
Advanced	O
Institute	O
of	O
Science	O
and	O
Technology	O
(	O
KAIST	O
)	O
and	O
the	O
National	O
Nano	O
Fab	O
Center	O
developed	O
a	O
3	O
nm	O
MOSFET	B-Architecture
,	O
the	O
world	O
's	O
smallest	O
nanoelectronic	B-Algorithm
device	O
,	O
based	O
on	O
gate-all-around	O
(	O
GAA	O
)	O
FinFET	O
technology	O
.	O
</s>
<s>
Normally	O
,	O
circuits	O
use	O
silicon-based	O
transistors	B-Application
,	O
but	O
carbon	O
nanotubes	O
are	O
intended	O
to	O
replace	O
those	O
.	O
</s>
<s>
The	O
transistor	B-Application
has	O
two	O
different	O
branches	O
that	O
meet	O
at	O
a	O
single	O
point	O
,	O
hence	O
giving	O
it	O
a	O
Y	O
shape	O
.	O
</s>
<s>
This	O
new	O
breakthrough	O
can	O
now	O
allow	O
for	O
nanocircuits	B-Algorithm
to	O
hold	O
completely	O
to	O
their	O
name	O
as	O
they	O
can	O
be	O
made	O
entirely	O
from	O
nanotubes	O
.	O
</s>
<s>
Arguably	O
the	O
biggest	O
potential	O
application	O
of	O
nanocircuits	B-Algorithm
deals	O
with	O
computers	O
and	O
electronics	O
.	O
</s>
<s>
Instead	O
of	O
taking	O
the	O
traditional	O
top-down	O
approach	O
,	O
the	O
bottom-up	O
approach	O
will	O
probably	O
soon	O
have	O
to	O
be	O
adopted	O
because	O
of	O
the	O
sheer	O
size	O
of	O
these	O
nanocircuits	B-Algorithm
.	O
</s>
<s>
Not	O
everything	O
in	O
the	O
circuit	O
will	O
probably	O
work	O
because	O
at	O
the	O
nano	O
level	O
,	O
nanocircuits	B-Algorithm
will	O
be	O
more	O
defective	O
and	O
faulty	O
because	O
of	O
their	O
compactness	O
.	O
</s>
<s>
Scientists	O
and	O
engineers	O
have	O
created	O
all	O
of	O
the	O
essential	O
components	O
of	O
nanocircuits	B-Algorithm
such	O
as	O
transistors	B-Application
,	O
logic	O
gates	O
and	O
diodes	O
.	O
</s>
<s>
They	O
have	O
all	O
been	O
constructed	O
from	O
organic	O
molecules	O
,	O
carbon	O
nanotubes	O
and	O
nanowire	B-Architecture
semiconductors	O
.	O
</s>
<s>
The	O
only	O
thing	O
left	O
to	O
do	O
is	O
find	O
a	O
way	O
to	O
eliminate	O
the	O
errors	O
that	O
come	O
with	O
such	O
a	O
small	O
device	O
and	O
nanocircuits	B-Algorithm
will	O
become	O
a	O
way	O
of	O
all	O
electronics	O
.	O
</s>
<s>
However	O
,	O
eventually	O
there	O
will	O
be	O
a	O
limit	O
as	O
to	O
how	O
small	O
nanocircuits	B-Algorithm
can	O
become	O
and	O
computers	O
and	O
electronics	O
will	O
reach	O
their	O
equilibrium	O
speeds	O
.	O
</s>
