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Progress Toward Single Molecule Transistors
Fungii writes "There is an amazing story over at sciencedaily.com saying two research teams have managed to create single molecule transistors, looks like we don't have to worry about limitations on feature sizes for a while."
...Hand soldering SMT's was a bitch!
"They do not preach that their god will rouse them, a little before the Nuts work loose." Kipling, 'The Sons of Martha'
The molecules involved in making the transistors, metal vanadium, are individually the size of golf balls.
;^)
Ryan Fenton
Everyone knows bigger is better.. What is with this obsession with making everything small?
Remember that there are limitations to how small we can make circuits. If you put two molecular sized tranistors very close to gether, you will have major issues with tunneling.
What next? Two transistors in a single molecule? The article doesn't say how well did that device actually function as a semiconductor, I quess it isn't the point.
In any case, I don't think anyone should go rush buy their stock. Semiconductor fabs are so expensive even evil multinational corporations have to team up to build them. I don't think this technology will compete withing next ten years (tm)
This means very little on a practical level at the moment; it's more an indication of what's possible than anything we're going to see actually used in the next few years (IMHO). It's an ongoing question just how small a transistor can get and still be functional, and this seems to be an answer to that: it can get molecule-sized. Whether a molecule-sized transistor can or will be actually be usefully incorporated in any practical device is another question (well, technically it's two other questions).
At the very least a practical device using transistors that small would have to have a radically different design from present-day circuits, including vastly larger error-checking capabilities and probably some self-repairing abilities. Heat is a problem even now, and in circuits on this scale it wouldn't take much for the circuitry to literally shake itself apart. Quantum effects, which are negligible on today's scale, would introduce all kinds of errors into both the input and output of such small circuits if you tried to simply copy the same structure onto the smaller scale.
Speaking of which, the issue of actually hooking in I/O at such a scale is both a major hurdle for some applications, and a major possibility for practical use in others. For example, this is the kind of scale you'd want if you're going to try to splice more-or-less traditional electronic circuitry directly into fine nerves; when the electronic eyes currently just coming into being become fine-grained enough to support normal vision, they'd probably need extremely fine connections to individual nerve fibres in the retina.
This is a real wowser of a breakthrough, and major kudos rightfully go to both teams. It shows that there's a long way to go before transistor-type circuits can't be made smaller. By the time we actually get that far down the Rabbit Hole it's likely that we'll also have other information-processing techniques available, such as quantum computing (and this technology, once developed, might be just what is needed to usefully access the output of qubit-based systems).
Current scale for transistors is about 90 nm
(current production technology is 130 nm).
Single molecule transistor scale would be 1 nm.
So oversimplifying a bit, this is 100 times
smaller than current tech.
The physics is such that the theoretical frequency response must be very high. The only problem could be capacitance on the input. I wonder about the gain, also.
As processing power increasse to 10-100 times what it is now, what will the role of software developers become? Will the additional power allow developers to ignore perfomance more and more, and focus on correctness and features? Or, will developers tackle bigger and bigger problems, and therefore require better asymptotic performance of their algorithms? I don't think computer science will ever die, but it's something to think about.
Further, Tour and his group have synthesized molecular transistors (he calls them "Moleisters") about a year and a half ago.
"Moleisters"?? What awful nomenclature, sounds scandalous. How about switching it around, call them "Transeculars." Hmm, that's not much better... But hey, it's all good, whatever helps them sustain an electron.
Weeks of coding saves hours of planning.
who cares if you cant actually use the damn thing
.13 or .9
mask costs are about $2million for
so its not the same and relatively few people can afford it
unless you share and then you can only really get engineering samples
AMD made the smart move of UMC and TSMC are just ARM/MIPS prod lines with some custom phillips stuff
IBM, Intel and maybe TI are the only people who can aford to do this anymore....
if you wanted me to put money on it I would bet IBM and the rest wither (yes Intel will outsource eventually)
regards
john jones
- Avoid conflating nanotech with chemistry.
- Avoid conflating nanotech with biology.
- Describe economical fabrication techniques that are not far more advanced than the nanotech being described.
We can be thankful that the referenced article succeeds on the first 2 counts. Unfortunately and quite preditably, it fails on the third count.Seastead this.
This is indeed grand news but there are many obstacles between developing a single molecule transistor and building microprocessors out of same. The difficulty with integrated devices is not whether or not a transistor of a given size will switch, but making the lithographic process of printing the things on the die accurate enough that they can be made that size in the first place. Also last time I looked the transistors on a microprocessor were not suspended between gold electrodes.
Noise may be another issue, since now we must be talking about handfulls of electrons so that a small number of rogue noisy electrons could push the signal across the noise margin and flip the logic.
Alternatively with that size of device we could be designing with high redundancy rather than relying on accuracy - a whole new design paradigm could open up.
Nemo me impune lacessit
Will the additional power allow developers to ignore perfomance more and more, and focus on correctness and features?
They already ignore performance and focus on (unneeded) features. Now there's only correctness to go.
...the power stability requirements of the Feild Effect Transistor...
FETs can be operated under a much wider voltage range than junction transistors.
In logic ICs, my "TTL Data Book" (Texas Instruments, 1976) the voltage requirement for bipolar chips is 4.5 to 5.5 volts for the 54 (military) family and 4.75 to 5.25 volts for the 74 family. On the other hand, for FETs, I have the 1976 "RCA Integrated Circuits" handbook, which mentions a 3 to 12 volts operating range for most of the chips in the 4000 family.
As for discrete devices in analog circuits, FETS and bipolar transistors are more or less equivalent in power supply needs, except that FETs behave as variable resistors in very low drain-top-source voltage ranges, so they are sometimes operated in close to zero or negative voltages, while bipolar transistors need at least 0.5 volts collector-to-emmitter to operate linearly.
Some programmable logic technologies handle wiring with a uniform sea of logic gates connected by fuses, and you create a particular logic circuit by selectively blowing fuses. The HP/UCLA rotaxane work involves essentially the same idea, using molecular switches at the intersections of a 2D grid of molecular wires. In addition to some discussion here on Slashdot, there is more at Nanodot, and a fairly extended discussion on sci.nanotech.
Solving the problem of routing specific wires to specific gates, and doing it in a way that's reliably manufacturable in mole quantities, will pretty much relegate today's foundries to niche markets. But that's probably a long way off, numerous problems to solve to get there. Interesting times ahead.
WWJD for a Klondike Bar?
Well, the Feild Effect Transistor may have that problem but 30 years ago Field Effect Transistors were being used to replace vacuum tubes. It was basically a tube bottom with the same pin layout as the tube and the FET with appropriate voltage dropping resistors. As a direct plug in replacement they had to work with the same power supply as had been the tube being replaced.
I see even classic Slashdot is now pretty much unusable on dial up anymore.