7. Today's processors are
made from silicon
but as it gets harder and
harder to make ever more
miniature circuits
processor technology has
moved from 90nm
fabrication in the mid-
2000s to a barely believable
7nm now or even 5nm by
2021 –
chipmakers are looking for
alternatives; not just
materials, but maybe even
biological components.
8. PROBLEM:
Modern processors have several billion transistors. That's been achieved
by cramming ever more transistors into the same amount of silicon.
but as you do that the laws of physics kick in and your processor starts
generating heat.
and the more power you want, the more heat you generate.
but to achieve that you needed liquid nitrogen to stop them burning
up.
9. SOLUTION 1:
Use silicon in a different way
For example, today's processors are largely flat.
rather than try to cram ever more transistors into the same amount
of space.
we could take an architectural approach and build up to make the
silicon equivalent of skyscrapers
10. SOLUTION 2:
we could take what's known as a III-V approach.
which uses elements from either side of silicon in the
periodic table.
Silicon is in group IV, so you'd use materials from groups III
and V in layers above the silicon.
This would reduce the amount of power needed to move
electrons around, which should make it possible to
manufacture transistors smaller and pack them in more
tightly.
The favourite candidate for III-V manufacturing is gallium
nitride, which has been used in LEDs for a few decades
and can operate at much higher temperatures than the
previous favourite, gallium arsenide.
12. Traditionally the CPU has done the difficult stuff while the GPU has handled
the graphics.
so for example in a game the CPU's doing the AI.
but the GPU's ability to do simpler tasks in massively parallel ways means
designers are increasingly looking at sharing the overall workload between
CPU and GPU based on their suitability for the job.
The more the GPU can do the better, because GPUs are massively parallel
circuits,
They have thousands of cores compared to the handful in a CPU.
Unlike CPUs, which are already pushing the limits of miniaturisation, GPUs
have a long way to go before the laws of physics ruin their exponential
growth.
13. CARBON
DATING:
• What if silicon runs out of road?
• Carbon could come to the forefront instead, in the form
of carbon nanotubes.
• IBM published a paper in the journal Science describing a new
method for creating carbon nanotubes from sheets of the
"miracle material" graphene.
• Unlike previous attempts, IBM's method didn't encounter
increasing electrical resistance as contact sizes were reduced.
IBM says that we may see carbon nanotube processors "within
the decade".
• Better transistors can offer higher speed while consume less
power. Plus, carbon nanotubes are flexible and transparent. They
could be used in futuristic 'more than Moore' applications, such
as flexible and stretchable electronics or sensors
14. GO ORGANIC:
• In 2011, researchers in Belgium created a plastic microprocessor by printing 4,000 plastic transistors on
flexible plastic foil.
• It's hardly a Core i7 – it can run one program consisting of 16 instructions – but while it isn't very
powerful, it's very cheap.
• And if research into roll to roll or sheet to sheet printing pays off, it could get cheaper still
• processors would be printed using organic 'inks'.
15. DIFFICULTIES:
For that to happen,
though, we'd need to
get much more accurate
organic printers .
while silicon processors
head for single digits in
the nanometre scale,
lab-scale printing is still
working in micrometres.
16. PHOTONIC PROCESSORS:
One of the most promising alternatives to silicon is to create
optical or photonic computers based on light.
In late 2015, researchers at the University of Colorado-Boulder,
MIT and Berkeley made a breakthrough: they combined
photonic circuitry and electronic circuitry on a single chip. "It's
the first processor that can use light to communicate with the
external world," said project lead professor Vladimir
Stojanović. "No other processor has photonic I/O in the chip."
17. QUANTUM
COMPUTING:
• Last but not least, there's quantum computing.
• Google's working on it and the first working quantum
processor was built at Yale in 2009, but it's exceptionally
hard to explain.
• Quantum computers aren't binary like traditional ones,
where 0 is off and 1 is on. Quantum numbers can exist in
multiple states at the same time, which means quantum
computers could consider multiple options simultaneously.
In a 64-bit quantum computer, each 64-bit register is
capable of holding 18,446,744,073,709,551,616 different
values at the same time. If you were to carry out some
computation, it would therefore be carried out on all those
values at once.
• There's an astonishing amount of money being spent on
quantum computing research by organisations and
governments, but for now it remains a far away if rather
tantalising possibility.