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Intel: Metal in Future Chips = Less Leakage (updated)
securitas writes "Intel is contemplating using metal instead of silicon in future chips for the 'transistor gate, which controls whether a transistor is on or off' and the 'dielectric, an insulating layer below the gate,' which are respectively made of silicon atoms and silicon dioxide. 'Millions of minuscule switches that make up silicon chips leak electricity when they're supposed to be shut off. To compensate, engineers have increased the current, driving up power consumption, decreasing battery life for portable devices and generating more heat.' AMD has also experimented with metal instead of silicon. By moving to metal AMD and Intel expect to reduce electricity leakage. More from AP via SeattlePI and the Miami Herald." Update: 11/05 15:25 GMT by T : Read on below for some information from Intel on why this is a good thing.
gManZboy writes "Following up on the Intel news that about using metal in chips -- here's an explanation from Shekhar Borkar (Intel Research Fellow) about why heat, power, and sub-threshold leakage, not transistor size, are the real challenges to Moore's law. Apparently, in order to make chips much faster, we're going to have to pump more electricity in then anything else in our houses -- and they'll soon be as hot as a nuclear reactor -- no, really."
The changes are largely necessary because of the unsavory consequences of Moore's Law, the famous dictum that states that the number of transistors on a chip doubles every two years. Yeah, it's all that pesky "Moore's Law" fault...
I swear I remember IBM moving to copper for chips a while back (C.2-3 years ago). Was it for production chips or just R&D purposes?
Is this just a question of Intel playing catch-up?
You see, diamonds are seriously overpriced luxury items. Although it is possible to manufacture cheap diamonds that are indistinguishable from the natural ones, it has never been done. Why? It would ruin the entire business model of De Beers & co. which is based on artificial scarcity. That's why they'd fight such projects to the bitter end.
The owls are not what they seem
This invention might save energy and lower carbon emissions. This is a good thing if it helps delay the next ice age, which is due in a couple of decades when the gulf stream conveyor collapses due to global warming. No use making very long-term plans, but anything that can delay the freeze until I move on to the next world must be tried!
I stole this
My course in VLSI design was many, many years in the past, but what I do remember is that early integrated circuits used metal gates in the fabrication process. That process was later abandoned in favor of polysilicon because poly was much easier to work with at smaller feature sizes (I'm a bit foggy on this one). Gee, so now we're going back to metal gate processes, and we'll have real metal-oxide-semiconductor field effect transistors again?
If this is becoming easier to do at deep submicron level, I suppose processes for making deep submicron feature-sized Gallium-Arsenide MESFET's also got easier? Now wouldn't we just love to have such GaAs chips on our desktops... (I do know I'm forgetting another difficulty in working with GaAs, anyone care to remind me why GaAs is not as common as silicon today?)
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
Has anyone actually checked the specs of the P4? Things like 15 cycle multiplies, 1.5 cycle ADC/SBB, etc
And yet it's still faster than virtually any other processor on the planet. Intel has come a long way from when it was being spanked by MIPS/Sun/etc. You can make an argument for Alpha, but that's about it.
a non-x86 core
The P3, P4, and Athlon cores aren't x86. They have a wrapper layer that translates x86 instructions into their own internal core instructions, but that's it. And, frankly, a more "efficient" core doesn't make a bit of difference if it doesn't actually have any use in the real world. The x86 ISA is here to stay for a long, long time. People have been predicting it's death since it came about, and yet it's managed to dominate every other ISA out there. Hell, it's being looked at for embedded use now of all things.
Why should the CPU do the work of a compiler at runtime?
Because the compiler doesn't know what the dataset is. You can make guesses, but that's all. If you really want to optimize then you have to actually run the program for a period of time using real world data and then re-compile with the profiling data you've gathered. Which is pretty damned expensive to do, and is invalidated if your data set changes (yeah, that never happens in the real world) or you want to sell the program to multiple companies (again, one of those rare edge cases). The fact of the matter is that it's far, far cheaper to upgrade the hardware than it is to spend a bunch of additional programmer time optimizing the software. You can whine and kvetch about this, but it won't change reality.
Back when I was in college and was taking EE/CompE courses I couldn't believe how crappy the x86 ISA was either. And it is crappy. So what? It's still faster than everything else out there, it's cheaper than the competition, and the world has boatloads of software that runs on it. Do you have any idea how much software is used on a daily basis that hasn't been touched in years? How much do you think it would cost to replace all that software?
Don't worry. One day you'll graduate too and after a couple years in the real world you'll discover that a crappy solution that fits the job is far, far better than a perfect solution that doesn't do anything.
The changes are largely necessary because of the unsavory consequences of Moore's Law, the famous dictum that states that the number of transistors on a chip doubles every two years
Moore's Law is only an empircal observation -- a convenient curve that fits through the our current data on time and transistor count. There are no gaurantees that this trend will hold for the future.
The point is that no physical phenomena forces the doubling. At best, one could say that mental and procedural limits prevent doubling faster than Moore's so-called Law. Perhaps this is the more interesting Law -- that doubling can't occur faster than every 18 to 24 months.
Two wrongs don't make a right, but three lefts do.
Now how can you say that CPUs are based off of alien technology when Intel is making changes like this?
The same way we've always been saying it -- emphatically
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That's not quite right. IBMs process uses copper as an interconnect between transistors. The contact to the device itself is still poly-Si.
when hooking devices together it goes something like:
transistor -> poly-Si contact -> TiN buffer -> Cu interconnect
There are 2 problems with putting a metal directly on Si:
1) electronically they don't match up and you get a barrier to conduction. This means you have to apply a LARGER voltage than you would with Poly-Si to even get it to conduct at all. The band structure of Si matches up with Poly-Si pretty well so the barrier is small, but the trade off is that Si is not as good a conductor as the metal.
2) Metals often react with Si and kill devices. Copper is especially good at this, which is why Aluminum was used as an intereconnect before IBM figured out how to do it right. The answer was a buffer between the Si and the copper that was a pretty good conductor but didn't react with either. TiN is common for this purpose.