
The missing switch: High-performance monolithic graphene transistors created - evo_9
http://www.extremetech.com/computing/132988-the-missing-switch-high-performance-monolithic-graphene-transistors-created
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guelo
From the paper [1]: "The concept's particular strength, however, lies in the
following property: within the same processing steps, many epitaxial graphene
transistors can be connected by graphene strip lines (the interface from
contact graphene to gate graphene is electrically transparent) along with
graphene resistors and graphene/SiC Schottky diodes (Fig. 2b), and therefore
complex circuits can be built up. As a special feature of graphene in contrast
to semiconductors, we anticipate that even a complete logic is feasible."

[1]
[http://www.nature.com/ncomms/journal/v3/n7/full/ncomms1955.h...](http://www.nature.com/ncomms/journal/v3/n7/full/ncomms1955.html)

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Scene_Cast2
Say, we end up with 100x faster but 100x bigger transistors. A core that's
100x smaller (transistor-count) is not necessarily 100x slower. With a 100x
clock speed-up, however - propagation delays will be the main limiting factor
for speed.

So, if this tech ends up being used, should I expect small, highly-pipelined,
single-core CPUs?

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ChuckMcM
One of the more interesting things here is the production process.

One of the _reasons_ companies work so hard to make small scale features is
that smaller scale means smaller die, smaller die means more devices per
wafer, cost per wafer is fixed, more devices at a fixed defect rate means more
yield (good devices), more yield means more 'value' per wafer.

Got that? The chain of events is predicated on the high cost of creating a
semiconductor wafer.

Now if instead you can 'print' the circuitry, and you do mixed signal stuff.
Then you can make your entire system as one board sized integrated circuit.
Think an LCD television (transistors on glass) where instead of each
transistor being the same you put a CPU and various other peripherals there.
Size is not as important but yield still is.

So for things like phones/tablets, if you can do LED pixels (vs LCD) then you
don't need the glass to be transparent (backlit) so you put down a layer of
display, then a layer of compute, then a layer of memory, and finally a layer
of radio. And voila, a device which looks like a piece of glass with black
scum on the back that lights up and makes phone calls if you put power to the
ends :-).

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bbrizzi
I might not understand the article correctly but only the contacts seem to be
made of graphene. The canal is still made of SiC with far lower conductivity
than graphene so it seems to me that the speed improvements wouldn't be as
tremendous as what the article claims. Don't expect 100 GHz CPUs landing any
time soon.

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ambertch
Yeah I was thinking about that too. Though if the limiting factor for
switching speed is the impedance of the interconnects (I'm guessing it is),
makes sense.

