“People have been talking about a new era of carbon nanotube electronics
moving beyond silicon. But there have been few demonstrations of complete
digital systems using this exciting technology. Here is the proof.”
Stanford Professor Subhasish Mitra
in a release from Stanford University
Computer Processor design just took a leap forward into the future with
the development of a proof-of-concept Processor based on CNT (Carbon Nanotubes)
as described in the article “First
carbon nanotube computer to help extend Moore's Law?”, published September
25, 2013 4:19 PM PDT by Eric Mack, CNET News.
For those with little trust in CNET News,
here’s the news straight from the Horses Mouth in the article A
first: Stanford engineers build basic computer using carbon nanotubes,
September 26, 2013, by Tom Abate, Stanford
University.
The leap forward was made on Wednesday September 25th 2013 by
the Stanford professors
Subhasish Mitra and H.S. Philip Wong at Stanford University. They had
help with designing this first 800nm CNT Processor, dubbed “Cedric”, from a few
Doctoral Students using the limited equipment available to them at Stanford to
make a CNT Processor:
1.
Max M. Shulaker,
2.
Gage Hills
3.
Nishant Patil
4.
Hai Wei
5.
Hong-Yu Chen
You can scope it out in the Nature Journal Magazine article “Carbon
nanotube computer”, Received 12 May 2013 Accepted 24 July 2013 by H.-S.
Philip Wong & Subhasish Mitra et al, Nature
Journal.
This first Computer based on CNT’s had only 178 transistors, the basic
building blocks of most Processors. At that count, it had the computing power
of a typical Intel 4004 Processor. In the process of making the CNT Processor,
they’ve solved several problems as relates to growing CNT and fabricating them
into a Processor.
To their credit, the Stanford Team didn’t have access to the Industrial
Fabrication techniques of companies like Intel or AMD (Advance Micro Devices).
They also had to content with the imperfect nature of these thinner than a
human hair CNT that are made up of Carbon Cages that since January 2013 can be
fabricated cheaply on demand and some of which once configured into a
transistor, refuse to switch on and off properly.
Imperfection-immune design – A
self correcting CNT Processor
As it relates to the manipulation of the CNT, they had to overcome
several problems, the main two being misaligned CNT’s and Metallic CNT’s. This
as the team aimed to design an Industrial process to manufacture CNT’s that
could be scaled up from the Lab to Fab, to quote Professor
Subhasish Mitra: “We needed a way to design circuits without having to
look for imperfections or even know where they were”.
Their design philosophy, called “imperfection-immune design” meant
building the CNT Processor to function even if it had physical imperfections
due to misaligned CNT’s and Metallic CNT’s a fraction of which appear whenever
CNT’s are fabricated. A complex algorithm was used to help the Processor cope
with the misalignments in the CNT’s used to produce the transistor logic gates
and the traces used to carry current in the Processor.
The problem of Metallic CNT’s was solved simply by burning them off.
Since the Metallic CNT, the ones that conducted electrons instead of acting
like semiconductor material that could be turned on and off like switches was
in the minority, they simply turned off the power to the good transistors and
powered up the entire circuit. The semiconductor material didn’t carry current
but the metallic gates did, literally burned away in puffs of Carbon Dioxide as
the heat helped to oxidized them.
Using this “imperfection-immune design” technique and the limited
fabrication facilities is what gave birth to the 178 transistors, suggesting
more was possible with Industrial scale facilities. The Processor basically
possesses the same power as an Intel 4004. Running a basic operation system,
most likely written in Linux, the CNT Processor is able to do the following:
1.
Counting
2.
Number sorting
3.
Running MIPS a commercial instruction set
developed in the early 1980s by then Stanford engineering professor and now
university President John Hennessy.
This design technique is an amazing achievement for a Processor built
using CNT as stated in “A
first: Stanford engineers build computer using carbon nanotube technology”,
Sept 25, 2013, Phys.org, which clearly paves the
way for CNT’s being built and tested at a commercial level, to quote Sankar
Basu, a program director at the National Science Foundation: “This 'imperfections-immune
design' (technique) makes this discovery truly exemplary”.
Advantages of CNT Processors –
Room Temperature Supercomputers
But the advantages of using CNT’s are obvious. Made up of a honeycomb Network
of Carbon atoms, they are superconductors at room temperature due to the
uniform pathways that the CNT creates for electron flow. Thus current flows
with almost zero resistance at room temperature and maintain their performance
even at elevated temperatures.
Because of their thickness, which is significantly smaller than a human
hair, they dissipate less energy and thus require smaller current to work,
Building Semiconductor transistors with time, though, is a challenge as their
superconducting capabilities means that they have to be specially fabricated so
as to reduce the formation of metallic CNT’s and are mainly semiconductors in
their electrical behavior.
Processors based on CNT have the capability to achieve clock speeds as
high as 10GHz, double that of the 5GHz FX-9000 from AMD as reported in my Geezam blog article entitled “AMD
unveils 5GHz and 4.7Ghz 8-Core Processor at E3 2013 in Apple’s Mac Pro Dogfight
for Top Gun in High End Multi-Core PC Gaming” but with much cooler
operating temperatures and with more stable performance.
Best of all, CNT Based Processors can already interface directly with
electronics built for silicon Chips, making them an easy slot in replacement
without the need to change the architecture of computers as they exist today. Throw
in the fact that merely adding strands of CNT’s to any compound makes it
structurally stronger, they are a perfect material for making Processors and a
replacement for using Silicon, the standard for years in Processor Fabrication.
That is, if you can grow them cheaply and uniformly in a streamlined
industrial process to make Processors. You can scope out more videos on YouTube
on Carbon Nanotubes
More options to expand Moore’s
Law – Optical, Quantum, Neural Net and now CNT
This development bears watching. Along with Optical Computers, Quantum Computers
as described in my blog article
entitled “Harvard
and Massachusetts Institute of Technology create Molecules from Photons - The
Force is Strong as Lightsabers, Optical Quantum Computers and Light Crystals
are Possible” and Neural Net Computers that mimic the function of the brain
by using Multi-core Processor Networks, CNT’s present yet another piece of
technology to keep Moore’s Law moving forward.
It’ll take some time to reduce the size of the Processor down to the
equivalent in the 24nm scale of the Intel and AMD Processor Fabrication World,
as the fabrication scale, again limited by the equiptment available to the
Scientists, was 800nm. This first CNT Processor, dubbed “Cedric”, has a long
way to go before it’s at that stage ready to slot into a ZIF socket to replace
a Silicon based Processor.
This may take years to achieve but as a first lays the groundwork for
their practical fabrication by 2015 the earliest to quote Supratik Guha,
director of physical sciences for IBM's Thomas J. Watson Research Center and a
world leader in CNT research: “These are initial necessary steps in taking
carbon nanotubes from the chemistry lab to a real environment”.
The first devices that’ll benefit when Stanford gets access to industrial
equiptment and can make an entire Processor out of CNT will be mostly mobile
computing devices i.e. Tablets and smartphones. Servers and Workstations will
benefit next especially form the fact that their operation is more stable at
lower temperatures and can provide higher speeds even while maintaining higher
processing speeds.
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