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."

Comments

Radiation hardening

[DigiShaman]

With transistors that small, how would you harden a microchip against radiation? Would the extra redundancy not make it worthwhile. That is to say, is there an optimal compromise between transistor size and resources consumed through redundancy allocation?

Re:Radiation hardening

[__aaltlg1547]

Normal computers aren't radiation hardened, but the point is that they store and process information based on more than just the quantum state of a single particle. It takes a great deal more unwanted energy to cause them to flip to the undesired state. This kind of thing would many times more vulnerable to stray radiation, heat or stray electromagnetic fields than the smallest conventional transistor.

But any practical computer is going to have to contain millions of these things. If you want to carry out a computation with such a machine, either you have to protect it with conditions that have a minimal chance of causing a computational error or you will have to engineer it with redundancy and error correction mechanisms that may in the end be bigger and less reliable than a classical solution.

Re:A transistor made of a single atom?

[artor3]

We were making single atom transistors ten years ago, but it was hit or miss whether the atom would end up in the right place.

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

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

Not to nay-say, but...

[koolguy442]

I hate being a nay-sayer, but the NYT article is making quite a spectacle about this whole thing. What the group has truly done is demonstrate a novel method for placing a single phosphorus atom within silicon and proceeded to measure the semiconducting properties of the resultant device with quite good precision. Because the doping is the result of a single atom, they can resolve more than just "on" and "off", and in fact can read three states from it, so it gets its quantum computing title.

As a materials scientist, I'm worried that they don't show any long-term data and all their results appear (from my not-so-thorough reading of the originating Nature Nanotechnology report) to be based on a single device. How repeatable is this result and how consistent are the signals across multiple devices? How far will the phosphorus atom diffuse over the lifetime of the device? Or even over the first few hours of its operation at room temperature? How closely can these devices be placed to each other on the silicon chip without getting cross-interference or depriving the dopant of its discrete quantum states? The dopants in a normal device aren't too terribly close to each other. And finally, how big must the surrounding structure be?

Don't get me wrong, this is excellent science and well deserving of its publication in such a prestigious journal, but the spectacle that the NYT is creating around this and the dreams of such a tiny device is a bit premature.