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Science Technology

Ohm's Law Survives To the Atomic Level 104

Hugh Pickens writes "Moore's Law, the cornerstone of the semiconductor industry, may get a reprieve from its predicted demise. As wires shrink to just nanometers in diameter, their resistivity tends to grow exponentially, curbing their usefulness as current carriers. But now a team of researchers has shown that it is possible to fabricate low-resistivity nanowires at the smallest scales imaginable by stringing together individual atoms in silicon as small as four atoms (about 1.5 nanometers) wide and a single atom tall. The secret is to introduce phosphorus along that line because each phosphorus atom donates an electron to the silicon crystal, which promotes electrical conduction. They then encase the nanowires entirely in silicon, which makes the conduction electrons more immune to outside influence. By embedding phosphorus atoms within a silicon crystal with an average spacing of less than 1 nanometer, the team achieved a diameter-independent resistivity, which demonstrates ohmic scaling to the atomic limit. 'That moves the wires away from the surfaces and away from other interfaces,' says physicist says Michelle Simmons. 'That allows the electron to stay conducting and not get caught up in other interfaces.' The wires have the carrying capacity of copper, indicating that the technique might help microchips continue their steady shrinkage over time and may even extend the life of Moore's Law. 'Fundamentally, we have shown that we can maintain low resistivities in doped silicon wires down to the atomic scale,' says Simmons, adding that it may not be ready for production now, but, 'who knows 20 years from now?'"
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Ohm's Law Survives To the Atomic Level

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  • Could be very useful (Score:5, Interesting)

    by Covalent ( 1001277 ) on Friday January 06, 2012 @09:30AM (#38608704)
    TFA says that the wires were deposited lithographically (the technique currently used to make chips) and then the phosphorus was deposited. So this, in theory, could be done cheaply.
    However, TFA also mentions low temperature. It doesn't measure exactly what temperature, but processors are not usually operated at low temperatures. If this is a "liquid nitrogen cold" temperature, then this could very well be useless on a grand scale. But if the effect survives to room temperature (or higher), then this could have a huge impact.
    Just a first order approximation would show that these wires are about 5 times smaller than the current 22nm state-of-the-art. In two dimensions, that means roughly a 2500% increase in density, enough to keep Moore's law alive and well for some time to come.
  • Re:Just a rant (Score:5, Interesting)

    by feedayeen ( 1322473 ) on Friday January 06, 2012 @09:40AM (#38608776)

    Likely because I just quit smoking and are somewhat grumpy, but I am tired of hearing about Moore's Law. Maybe those in the semiconductor industry care about it, but I, and those I work with certainly don't. At what point will we stop hearing about it? /rant

    (Thank you for your patience. Now where are the damn pretzels?)

    The most important part of Moore's Law was it essentially saying that your new toy will be far better than your old one before it even breaks. When the rate of doubling gets closer to 10 years, buying a new computer isn't going to be so much as the new toy is faster but rather the old toy broke. Once that driving force is over with, electronic companies will be talking about other ways to produce money in more mundane ways.

  • by jpapon ( 1877296 ) on Friday January 06, 2012 @09:50AM (#38608848) Journal
    If it's liquid nitrogen cold, wouldn't it make more sense to just use a high temperature superconducting material? I wonder if nanoscale wires made from something like TBCCO would still be superconducting? I don't see why they wouldn't, but I also am not really knowledgeable in the subject area.
  • The wires are composed of doped silicon, and features of doped silicon are at least several atoms big. It may be made of bunch of atoms of dopants, but they are embebed on a crystal dozens of atoms wide. Also, the wires ccertanly an't work without those dozens of atoms, and another wire can't be as close to share some of those atoms without being connected. For all practical porposes, the wire is dozens of atoms wide.

    Why can't /. just anounce a semiconductor breakthrough for what it is? "Smaler wire made of silicon" would make it, for exemple.

    And, by the way, Ohm's law holds at the atomic level as well as it holds for big conductors. People learned that by studying organic conductors ages ago. The problem is how to make silicon work the same way. That is what TFA seems to be about (don't really know because it is behind a pay wall).

  • Nano-insulated wire? (Score:4, Interesting)

    by Muad'Dave ( 255648 ) on Friday January 06, 2012 @10:32AM (#38609244) Homepage

    It sounds like they've created nano-scale insulated wire, kinda like myelin-coated nerve fibers.

To write good code is a worthy challenge, and a source of civilized delight. -- stolen and paraphrased from William Safire