Graphene FET on diamond for high-frequency electronics (2021)

by nynx • 4 years ago

35 22 4 years ago

rbanffy4• 4 years ago

Am I the only person here who wants to put ~60 thousand of these on a chip and make a 54 GHz 6502 for a ridiculously fast Apple II?

Could be a Commodore 64 or Atari too ;-)

tspiteri• 4 years ago

Would it work though? The transistors are quite large compared to today's processor's transistors, and at that high frequency the routing delay for the signal to travel around transistors is quite significant. This seems more useful for a low-transistor-count high frequency device.

rbanffy4• 4 years ago

It’s more useful for the intended uses. OTOH, it’s always fun to misuse technology.

There would need to be multiple carefully positioned clock entries or a fully asynchronous design rather than just a copy of the NMOS layout, but it’d still be a lot of fun.

jacquesm3• 4 years ago

Why 60000? Do you mean both the CPU + the RAM and peripherals chips?

rbanffy4• 4 years ago

Wow. I was off by an order of magnitude. With 50K you can probably do a complete Apple //e!

deegles• 4 years ago

I wonder what the hashrate would be if this was used for a bitcoin ASIC…

amelius2• 4 years ago

Always look at performance per dollar, not absolute performance.

Nevermark2• 4 years ago

Well not quite.

In this case rewards are highly nonlinear, not proportional to processing work at all.

The value measure is how good performance is relative to competitors, with a vastly greater than linear reward if it is

I expect energy use (and other performance costs) do not matter much once your winning proof-of-work competitions due to higher performance (as apposed to simple scaling of hardware)

Given this is an experimental device it’s probably only the fab cost that is a barrier

londons_explore• 4 years ago

Looks like a market opportunity for de beers...

foxyv2• 4 years ago

With the current prices of graphics cards, it may be more economical to make them out of diamonds...

caleb-allen• 4 years ago

I know you joke, but with the existing costs of fab manufacturing I wouldn't expect that using a diamond substrate would take up that much of the cost.

New diamond manufacturing processes include chemical vapor deposition, which would make integrating with fab processes pretty feasible. I'd guess it depends on weighing the performance graphene can offer vs the cost increase over silicon.

foxyv2• 4 years ago

New diamond manufacturing processes include chemical vapor deposition, which would make integrating with fab processes pretty feasible.

That is honestly pretty freaking cool.

atoav• 4 years ago

Afaik synthetic diamonds are nowhere nearly as expensive as natural ones. Diamonds are just carbon after all.

thfuran• 4 years ago

So far as I know, no one can grow diamonds as big as wafers so I think it's sort of moot. Some other process like vapor deposition would probably be used rather than starting from a giant block of diamond.

gene-h• 4 years ago

it's cool, but the problem with previous graphene transistors is that they didn't really have a bandgap, meaning there wasn't much of a difference between on and off, making them unsuitable for use in computers. It looks like that could be the case here too.

xyzzy21• 4 years ago

Nice BUT. The actual frequency/clock rate of a system is NOT defined by the transistor Ft value - it defined by the parasitics of the circuit it's placed into. If you build an IC with something like this, the claimed Ft does NOT define or allow the building of something far beyond the frequency or clock of what we have now. That is the fundamental flaw of both the PR by groups announcing such things and of non-EEs reading about them.

Graphene FET on diamond for high-frequency electronics (2021)

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