Slashdot Mirror
Aussie, Finnish Researchers Create a Single-Atom Transistor
ACKyushu writes "Researchers from Helsinki University of Technology (Finland), University of New South Wales (Australia), and University of Melbourne (Australia) have succeeded in building a working transistor whose active region comprises only a single phosphorus atom in silicon. The results have just been published in Nano Letters. The working principles of the device are based on sequential tunneling of single electrons between the phosphorus atom and the source and drain leads of the transistor. The tunneling can be suppressed or allowed by controlling the voltage on a nearby metal electrode with a width of a few tens of nanometers."
Well, at least this seems to set an ultimate limit to Moore's law, since it's not very easy to go to less than one atom per transistor.
The devil is in the details. The "Active" region is only 1 atom wide, but the gate is still "10s of nanometers" Last I checked, the gate was still part of a transistor. We're currently mass producing with critical dimensions at 34 nanometers where I work. Granted, this is sweet, knowing that a transistor's active region can be that small. Still, the limit will really be placed on reproducibility. I mean, placing a single phos atom in the middle of a silicon chip at just the right location? That kind of technology being moved into the semiconductor industry for mass reproduction and economies of scale is still a long ways out and I personally think Moore's law will lose steam before then.
We've had single Atom CPUs for some years now... :)
Don't overheat those Phosphorous atoms....
http://michaelsmith.id.au
If the state of a gate depends on one electron, it will be highly sensitive to radiation. So what do we do ? Embed these in large blocks of lead ?
Well, at least this seems to set an ultimate limit to Moore's law, since it's not very easy to go to less than one atom per transistor.
Yes, a single atom should be small enough for everyone.
...Wouldn't that be kinda hard to read?
Notice that this discovery was NOT published in Nature. Wonder why? Here's why: http://en.wikipedia.org/wiki/Jan_Hendrik_Sch%C3%B6n . Stay skeptical, wait for replication.
- "Hear that?! The percolations are imminent! Cease your ingress!"
This thingy is just a research device, just good for research. It's not a precursor of anything practical.
It's been known for many, many years that there are serious tradeoffs to be pondered when you shrink transistors (and FETs).
Your basic linear dimension versus surface area versus volume scaling laws are in full play here.
You win at first, as smaller base or gate lengths lead to more speed, and less surface area means less capacitance to charge up.
But below a certain size the rapidly shrinking cross-sectional area reaches its current-carrying capability, while noise and leakage loom large.
Right now the low-level chip designers, with their 10^12 atom transistors are already spending a large part of their time with these issues. The challenges are not going to go away, they just get larger as one attempts to shrink things even more. It's unlikely that these hard challenges can be overcome to span the million-million times distance to a true one-atom transistor.
So don't put any big money on ever having one-atom transistors in any practical device.
Then how would you call a Field Effect Transistor?
No. A valve uses charge carriers (electrons) floating in a vacuum. A transistor uses either electrons or holes in a semiconducting solid as charge carriers. A semi-conducting solid is not as close as possible to a vacuum.
Would be designed around a Higgs Boson which would know when to come back from the future and switch with no gate delay...
Then how would you call a Field Effect Transistor?
Nice try with the bolding of F,E,T. Perhaps, with your use of "how" instead of "what", you are not native English, and don't understand the use of "sic". This is often used to denote a particular term/phrase/whatever which the writer considers incorrect, but which is being quoted nevertheless as-is. The fact that a FET is called a FET doesn't mean it is a transistor, any more than the Democratic People's Republic of Korea is democratic, for the people, or a republic. You thus still call the DPRK the DPRK, as you call a FET a FET, because those happen to be the best-known names, but you don't call the DPRK a "democracy" and you don't call the FET a "transistor".
Now, the evidence, from the horses's mouth. Read the quote in the left hand column by the guy who named the transistor. He named it so because it - "it" being the point contact transistor and devices descended from it, such as the modern BJT - had transfer resistance, the dual of the vacuum tube (or FET) which is defined in terms of its transfer conductance. Understand?
A semi-conducting solid is not as close as possible to a vacuum.
A substance comprising one atom is as close as possible to a substance comprising no atoms. My comment was somewhat tongue-in-cheek, designed to illustrate the danger of imprecision. In particular, the discovery is /not/ of a one-atom transistor, or even a one-atom FET, it's of a FET with a single atom channel. The other AC seemed to understand this.
That kind of technology being moved into the semiconductor industry for mass reproduction and economies of scale is still a long ways out and I personally think Moore's law will lose steam before then.
I would say it's pretty much lost steam already. If you take a function that can't exploit multiple cores, then the single core performance has not improved much in a while. More cores is a "cheat" that extends it somewhat but I doubt 10+ cores makes any sense for end users so it won't scale much further than it already has.
The other bummer is power, even though there's a massive focus on power savings now running a CPU/GPU at 100% draws more and more power. The latest AMD offering, the HD 5950 is bumping the head into the 300W ATX limit, and most agree it's designed to overclock for more. Or it is perhaps the same bummer, since it's the main reason 10GHz+ cores aren't practical.
Fortunately, I think there'll be a lot of innovation in other areas, particularly in networking (fiber, 4G mobile broadband), storage (SSD) and form factor (think iPhone, Wii controller, OLED displays and whatnot).
Live today, because you never know what tomorrow brings
Not for my imaginary girl friends, you insensitive clod!
I would say it's pretty much lost steam already. If you take a function that can't exploit multiple cores, then the single core performance has not improved much in a while.
Moore's law does not describe performance.
"Just because one researcher commits the "biggest fraud in physics in the last 50 years" that happens to involve transistors doesn't mean all such research is fradulent and there is no reason at all from your link to be more skeptical than normal about this research."
Ahhh, a swing and miss, I felt the wind from that one though! I'm afraid that you (and the schizophrenic raving lunatic AC responding just before you) are making rather unwarranted assumptions about my comment. I never suggested "all such research is fradulent [sic]". I am suggesting that in a field where the science is currently progressing at breakneck speed and is consequently ferociously competitive, at the absolute cutting edge of the cutting edge of materials science and single atom manipulation, a breakthrough discovery as important and consequential as this needs to demonstrate replicability before the provisional acceptance warranted by the evidence in this paper alone can be elevated to the level of confident belief in the phenomenon being demonstrated. So yes, there is rational reason to be a little "more skeptical than normal about this research" because extraordinary claims require demonstration of a commensurate (ie. more than normal) level of extraordinary evidence in their favor before being accepted as solid fact. This is how science and rational skepticism works. Trust, but verify.
- "Hear that?! The percolations are imminent! Cease your ingress!"
10GHz cores are not something you want to sit next to without proper shielding it's possible you could be burned. It was a concern back when we were approaching single core 5GHz before the dual core processors came out and everyone was speculating we would be at 10GHz in 3-5 years. That was about 6 years ago I believe.
FWIW, phosphorous will burn water. It pulls the oxygen away from the hydrogen. So in my high school chem lab it was stored under kerosene instead. Quite mind boggling at the time.
So if you're going to worry about spontaneous combustion, perhaps you should cool your computer with kerosene rather than water.
I think we've pushed this "anyone can grow up to be president" thing too far.
Scientists are just as online and wired as the rest of the world... they email each other, read each others papers and attend conferences regardless of nationality. Just imagine one researcher reading the usenet post or paper of someone else doing the same type of work as her... of course they will contact that person.
:) )... A few days after showing him sci.biology(or whatever) and how to post he was so excited that he had already made contact with 4 or 5 people around the globe engaging in similar areas of research as him... It was truly an eye opener for me as to how powerful the Internet was going to be and how it would impact the world some day... alas I did not anticipate rickrolling or LOLcats...
A real story from me was when I was at university and introduced a friend of mine(doign a PhD in microbiology) to USENET... this guy had never used or really heard of the Internet as it was quite new(and I am old
"The results have just been published in Nano Letters."
I'm guessing that'd be a Times New Roman 0.0000001 pt font then? Damn, I left my scanning electron reading glasses at home today.
It gripped her hand gently. 'Regret is for humans,' it said.