Physicists Create a Working Transistor From a Single Atom

stupendou writes "Australian and American physicists have built a working transistor from a single phosphorus atom embedded in a silicon crystal. The group of physicists, based at the University of New South Wales and Purdue University, said they had laid the groundwork for a futuristic quantum computer that might one day function in a nanoscale world and would be orders of magnitude smaller and quicker than today's silicon-based machines."

Re:If its embedded in a silicon crystal....

[jo_ham]

Pretty much - that's how transistors work. The phosphorous has a extra electron (compared to the silicon) and the combination forms an extrinsic semiconductor, which you then use to make junctions and transistors and diodes etc.

Just having the phosphorus atom isolated doesn't do much for you, so I think the article is referring to "silicon based computers of today" without really thinking about it properly - you still need to dope it to make it useful for making computer chips, despite it already being an intrinsic semiconductor.

Transistor made from multiple atoms

[enriquevagu]

They make a transistor from multiple atoms, all of them silicon but one, which is phosphorus. That is NOT a transistor made from a single atom (as the title suggests). Great advance, in any case, but misleading title.

Re:A transistor made of a single atom?

[cold fjord]

Today, we can place the atom with high precision, in silicon, so that the devices can be made reliably.

Cornell demonstrated a single atom transistor [eetimes.com] nearly 10 years ago, and today we are still pretty much at the level of demonstrating / playing / investigating.

Ten years from now, who's to say we won't be able to mass produce them?

It is a pretty big jump from building a single demonstration / proof of concept device and connecting it and integrating it into a design that works reliably at speed. IBM seems to be getting some interesting results with a single atom DRAM [eetimes.com], but that is still way closer to a laboratory curiosity than an option for shipping silicon.

But that is just the Fab side of things. To actually design and build chips with this sort of technology is almost certainly going to require some serious upgrades to EDA tools.

Re:A transistor made of a single atom?

[cold fjord]

That's what I said... that we've been able to build these things for ten years.

Yes, and this is what you didn't say: and today we are still pretty much at the level of demonstrating / playing / investigating.

Did you lose interest after getting to the end of what you wrote?

Did you read how they did it?

The scientists placed the single phosphorus atom using a device known as a scanning tunneling microscope. They used it to essentially scrape trenches and a small cavity on a surface of silicon covered with a layer of hydrogen atoms. Phosphine gas was then used to deposit a phosphorus atom at a precise location, which was then encased in further layers of silicon atoms.

Does that seem like a scalable process to you? Here is what the article says:

While offering astounding precision for research, these microscopes are not currently applicable as manufacturing tools to make chips that contain billions or even trillions of transistors. Moreover, the devices now operate at very low temperatures.

Ah, good! They made them with a method not applicable for manufacturing, and, as a bonus, they are cryo-cooled. Lovely. They are still at the level of demonstrating / playing / investigating.

Re:Radiation hardening

[pz]

Are normal computers radiation hardened?

Yes. They are hardened against the normal background radiation that is ubiquitous. That's why there's more-or-less a minimum amount of energy that's required to change a single storage bit, otherwise it gets flipped too easily by a stray alpha decay from the chip's packaging. We entered the era where packaging is made from low-radiation materials some time ago to help with this, but it only helps, since existenace here on Earth is bathed in a certain level of radiation.

That isn't to say normal chips are hardened against abnormal levels of radiation, but they most certainly are designed with a given level of anticipated background.

Re:Heisenberg says "NO"

[dsgrntlxmply]

Despite difficulty in following the overall argument given, tunneling leakage already became a significant factor several process generations ago. That was the reason for moving to high-k dielectrics: increasing the dielectric constant of the gate insulator material allows the insulator to be thicker (thus lower incidence of tunneling across the gate) for a given capacitance.

Re:Not to nay-say, but...

[GerhardKlimeck]

The devices built in this form have been tested against temperature cycling. They have in fact traveled across continents for testing and examination. The NY times accurately reported my qualification that this cannot be mass produced (yet) and is limited to low temperatures. I see no hype in the NY Times story. I am one of the authors of the paper.