Slashdot Mirror
CNFET Rivals Silicon Performance
Baldrson writes "Applied Physics Letters is carrying a paper on a CNFET (carbon nanotube field-effect transistors) advance that now rivals silicon performance for both n and p type devices. There is also a New York Times article in which it is reported that "it would be
two to three more years before I.B.M. was ready to work on
prototypes of future nanotube chips and as many as 10 years
before they would be commercially available". This is may be what's at the end of the road for CMOS."
On top of this, look at the on-chip SMP work that the major processor manufacturers are working on. They're working on being able to run multiple virtual CPUs, sharing the same execution pipelines and caches, so when one thread is doing a lot of multiplication work, another may be able to use the addition and general flow pipelines. Allegedly, in simulations, the multiple virtual CPUs end up executing at about 70% of the efficiency of real, individual CPUs, all with very little extra silicon.
On top of that, manufacturing is improving to the point where yields are very, very high. This means it's becoming more fesible to make larger and larger dies with more and more on them without significant failure rates. I think we'll soon see larger caches and wider buses. 64-bit CPUs may be a brief stepping stone to 128- and higher-bit.
Add to this the current focus of Linux, which is Linux on mainframe architectures. The thing is, the very same principles that make mainframes such wonderful beasts are what we're starting to see in the hardware we'll be seeing in the near future. The multi-threaded hardware above, and split-bus architectures both have mainframe parallels. Linux should be ready to take advantage of the new hardware years before Windows is making significant use of it.
Lastly, the increasing popularity of the Mac and the commoditization of game system components means that we're seeing more and more markets for faster general purpose CPUs. This means more competition and, because of that, better funding for research.
We may yet push ahead of the oft-misquoted version of Moore's law! :)
Says the RIAA: When you EQ, you're stealing bass!
Another advanced technology which may replace ilicon in the near term is spintronics. These devices have one advantage over nanotube transistors in that they may easily implement quantum computing...
Since the IBM experiments (and others done elsewhere) almost always use single wall carbon nanotubes, there are a few issues of practical nature I wonder about with this technology.
One is that single wall nanotubes are oxygen sensitive. Specifically, contact with O2 will cause single site defects in the nanotube structure, thus causing the whole nanotube to lose its electronic properties. It makes me wonder about how they will package these "molecular transistors" such that O2 can't get to it, but the encapsulation of the nanotube doesn't cause it to short out.
Another is that when these things heat up, they do ignite. As we've seen with the light-based ignition shown in Science and here on slashdot, these materials do burn. The above mentioned oxygen reaction sometimes causes the semi-conducting nanotubes to become insulators, thus they heat up, ignite, and disintegrate. So I'm wondering if frying one's nanotube-based chip would be more than just a figurative term if this happened.
Finally, there is the fabrication issue. I know that in the near future, one can make kilotons of nanotubes, and probably even kilograms of single wall nanotubes today (maybe 2kg a year, but you don't need that much if you only need 1 nanotube), but how are you going to fabricate them into architechures onto chips with existing chip fabrication technology?
Maybe IBM has all this worked out. I do have to remember that what they've published today is what they already have covered in patents and what they've been working on already for several months to one year. They don't publish unless they've got more going on AND if they already have the technology protected.
an entertaining idea, even if it simply reduces power output... I can't get the whole text, but it seems like 1 V transistors should allow faster clock speeds (especially since processor speed isn't really much related to transistor speed but rather to cooling speed)