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.

Comments

Problems to come

[brejc8]

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%.

First use of this technology...

[ipsuid]

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.