Single-Atom Transistor
Acid-F1ux writes: "Using a single cobalt
atom as a switch, a research team at Cornell University has demonstrated a
working transistor only 1.3 nanometers in length. Silicon transistors today are
generally more than 100 nm long." We posted a slightly more general article about nanotransistors recently, too; this one concentrates on the Cornell researchers.
When you get transistors the size of 1nm the time it takes for a clock signal to travel from one side of a 10mm chip to the other gets to millions of gate delays.
Current high speed processors have about 10 gate delays between clocks (and dropping).
The only way to keep devices increasing in speed along with the technology is to move to non clocked systems at least for long distance communication. This can be
done by GALS (Globally Asynchronous Locally Synchronous).
Also at that size transistors become rather unpredictable. Comes take a ps to switch sometimes three times more. You will no longer be able to say this pipeline stage
will be completed by x ps because sometimes it might not be. So margins become so large that most operations take only 50% of the time allocated.
My research is into Delay Insensitive circuit conversion. Basically you know when the pipeline stage is completed. This improves speed and copes with fluctuations in
voltage, heat or lazy transistors.
I tried it out on a MIPS R3000 clone and got 30% speed improvement. I'm hoping for 50%.
Mouse powered Chips, Open source Processors and Lego
After reading the article, it seems that this is a complex of silicon, gold, hydrocarbons, etc. all combined into a system that can manipulate and detect a state change in a single cobalt atom. While a major accomplishment (previously quite a bit more stuff was needed to manipulate and detect single atom state changes) I would hardly call it a single atom transistor.
I know I shouldn't, but I simply can't help bringing up one of my favorite Strange Matter comics.
Oh...
Wait, where did I put it?
Find free books.
I'm re-reading Neil Stephenson's work. In his piece, the nano-mites were around 130 nm, and used rod-logic for computations.
This seems far more likely, because it's under the 'little-yellow-different-better' variety, all the major players will still be in place as it is today.
I SHUDDERED when I followed this line of thought and realized we are more likely to see an MS NanOS within the timeframe of Diamond Age, than the anarchistic/utopia. I can't say I can claim which is better.
Let me off this rock now, please.
Before I part with'em: two pennies weigh ~4.996+/-0.014g, have a zinc core, and the face of Lincoln. You can keep 'em.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
By sensitivity to "environmental" factors, I'm sure they are referring to light.
Requiring cryogenic cooling for operation, it will be a long time before we see these "transistors" in a CPU humming under our desk.
An application we are likely to see for this technology in the near term is supersensitive CCD imagers for use in devices such as the Hubble. Having the switching element consist of a single atom is likely to make each transistor sensitive to single photons of light, with the proper cooling and biasing.
From reading the article, the biggest trouble with these devices is they all share the same gate (the silicon substrate). So for real world use we are still no further ahead... in other words, still dependant on the feature size we can produce using lithography techniques on silicon.
It appears Ockham lost his razor and grew a beard.