Perv-y Material Heralds Move From Silicon 45
RalphTWaP writes "The Register has posted this report about the successful use of perovskite oxides as a replacement for silicon oxide in chip manufacture. As the Reg reports, the journal Science contains the original article. Best of luck getting at it though. Perhaps that kind of thing is what this other article was talking about."
Well, not really getting rid of silicon... (Score:2)
A few bits from an insider. (Score:5)
[For the nosy kind of people who like qualifications: I'm a collaborator of Dr. McKee. See for example Lin et. al., "Epitaxial Growth of Pb(0.2)Zr(0.8)TiO3 on Si and etc.", Appl. Phys. Lett. 78, 2034 (ref. 27 in the Science article) on which I am an author.]
First, this technology is not enormously new. It's gotten into Science now, which makes it more high-profile, but it dates back at least to a publication in 1998 (McKee, Walker, and Chisholm, "Crystalline Oxides on Silicon: The First Five Monolayers", Phys. Rev. Lett. 81, 3014).
People have been trying to put perovskite oxides on silicon for quite some time (see, e.g., Refs. 12-15 in the PRL paper), for various reasons. [By the way, the prototypical perovskite oxide has the form ABO3, where A is a 2+ cation and B is a 4+ cation; the structure is cubic with a unit cell consisting of A at the vertices, O centered on the faces, and B in the center of the O tetrahedron. They're named after the original "perovskite" mineral, CaTiO3. It has nothing even remotely perverted about it. So get your mind out of the gutter.] One of these reasons is, as the article mentions, gate dielectrics (insulators) for field-effect transistors. A field-effect transistor consists of a conducting channel, usually made out of a semiconductor. By applying an electric field to the semiconductor you can enormously change the conductivity of the channel. However, you don't want the electrode you use to apply this field to short to the channel, so you have to put an insulator in between. There is a lower limit on the thickness of the gate insulator imposed by the desire to limit the leakage current between the gate electrode and the channel. By switching insulators, you can extend this limit.
Another use is for capacitors in DRAM. A DRAM cell works by either storing or not storing charge in a capacitor. The capacitor has to store a certain charge (~10 000 electrons) to be reliably read as on or off. If you recall the definition of capacitance Q = C V and the parallel-plate capacitor equation C = epsilon A / d (epsilon is the dielectric constant and depends on what material you put in the capacitor; A is the area; d is the spacing between plates; V is the voltage across the capacitor), you realize that there are four ways to increase Q: increase V, increase epsilon, increase A, decrease d. V is set by the operating voltages in the device, and there's a lower limit on d, again, due to leakage. You want to decrease A as much as possible to squeeze more cells on the chip. So one attractive thing to do is to switch to a material with greater epsilon. Perovskite oxides give you that opportunity.
Perhaps the most exciting use of COS at the moment is to integrate ferroelectric materials with silicon. Ferroelectrics (e.g. BaTiO3, (Pb,Zr)TiO3, both of which are perovskites) are materials with a permanent electric polarization, just like ferromagnets have a permanent magnetic polarization. You can use this permanent field to store data by switching its direction (hence the notion of a 15-year state in a processsor). One particularly attractive way to do this is to replace the gate dielectric in a field-effect transistor with a ferroelectric. Since the ferroelectric has its own built-in field, the transistor remains on or off without your putting in a gate voltage, and even when you power down the device. Hence you can set the state of a processor built from these things, walk away, and come back years later and it will still be there. These materials are also candidates for use in devices to replace Flash memory and that ilk.
I'd go on but I'm supposed to get back to work
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Re:Don't even mention (Score:1)
Don't even mention (Score:3)
The Register article is woefully short on details, so it's impossible for me to say whether or not a perv RAM system would be inappropriate. (name aside) I would have liked more information, but the supposed like to the journal "Science" just led back to slashdot. Then again, maybe IE is being flaky.
Re:Well, sort-of (Score:1)
Re:Other ramifications (Score:4)
Caches already don't need (much) power to refresh. They're made of CMOS SRAM, which means that they only dissipate a lot of power when their state changes (ideally they'd dissipate none when the state isn't changing, but there's leakage current across gates and across junctions to the substrate).
Caches are power-hungry because any access has to a) do a tag lookup and b) propagate itself across the entire cache. There are tricks you can use to reduce the power cost of this, but this will still dominate by far over static power requirements.
Heat generation within both caches and the chip core is mainly caused by changing states and shuffling information around, not by maintaining an existing state. I've been studying this for a few years now
Other ramifications (Score:3)
This might also increase clock speed from heat issues, as well as no need for dead refresh cycles in the cache.
I wonder how much the new stuff costs. Hopefully its dirt (sand) cheap.
Sounds like the setup for a joke (Score:2)
I put yttrium barium copper oxide and perovskite oxide in a room and let them fight it out.
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Poliglut [poliglut.com]
Abstract, URLs and comments (Score:4)
"We show that the physical and electrical structure and hence the inversion charge for crystalline oxides on semiconductors can be understood and systematically manipulated at the atomic level. Heterojunction band offset and alignment are adjusted by atomic-level structural and chemical changes, resulting in the demonstration of an electrical interface between a polar oxide and a semiconductor free of interface charge. In a broader sense, we take the metal oxide semiconductor device to a new and prominent position in the solid-state electronics timeline. It can now be extensively developed using an entirely new physical system: the crystalline oxides-on-semiconductors interface."
URLs Abstract [sciencemag.org] and article [sciencemag.org] (subscription may be required...)
My summary:
Oak Ridge National Lab scientsts demonstrate "crystalline oxide semiconductors", that are a combination of Ba-SrO and SrTiO3 on Silicon or BaTiO3 on Germanium. The cool thing is it looks like this will enable germanium field effect transistors that could switch faster than the 210 GHz Si-Ge transistors that IBM can now produce.
from the make-it-faster dept (Score:2)
Haha! (Score:2)
Here's a working link...
http://www.sciencemag.org/cgi/content/abstract/29
... okay, it's not REALLY working. You have to buy access! Wasn't there a protest by scientists about this kind of thing?
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Re:What? (Score:1)
See the above post "a few bits from an insider" by AC, and note the part about ferroelectric materials.
What got MY attention about this is the high temperature superconductor YBa2Cu3O7 has a perovskite structure, and I seem to recall being told that a similar material (slightly deficient in oxygen) is a semiconductor. This same technology may lead to the integration of Josephson junctions into microchips.
New Micro$oft Slogan! (Score:2)
Re: good luck trying to get through (Score:3)
I suppose it is hard to get through with the wrong link:)
Try this one [sciencemag.org] instead(Reg required).
Re:Don't even mention (Score:2)
Let's say you do make RAM out of this stuff. Now let's say your box hangs so badly you must power it off. Would you want it to return to the same state? What mechanism could be used to reset the RAM?
Current motherboard designs will work just fine. When you turn on or reset the motherboard, it resets the processor, so even if it and the RAM maintained state, the instruction pointer wouldn't be pointing at the same place, but rather at some location mapped to ROM, which would start the POST, etc. From that point, it clearly wouldn't matter, because your BIOS is going to be written such that it doesn't randomly execute unitialized memory.
Re:A few bits from an insider© (Score:1)
Re:Well, sort-of (Score:2)
Several major companies have a lot of money invested in this, with IBM leading the pack last time I checked.
-= rei =-
Re:Other ramifications (Score:1)
Re:Don't even mention (Score:1)
Well, sort-of (Score:1)
But only if you turn it back on within 15 years!!
Of course /. editors check the articles (Score:1)
I wonder how hard it would be to get a goat-lovin' link into a posted article
Why "Perv-y"? (Score:1)
If you're really sad enough to have to seek innuedos in such a way, then this text (from the other useful link out of the four included) "Specimens can remind one of darkly colored cubes of galena. But galena's better metallic luster, greater density and perfect cleavage will give nobody any trouble in permanently confusing the two." should provide more joy.
Tom.
another article (Score:1)
Not that i understand it....really.....
Re:Super efficient insulators? (Score:1)
guess I never knew that (Score:1)
Super efficient means low-loss. (Score:1)
What they mean by "super efficient insulator" is that the these dielectric materials are low-loss. In other words, the stored fields will not be degraded by the absorption mechanisms in the material like typical electrically insulating materials.
Thermal conductivity of a material is related, but not as close as you might think.
Re:Quantum interference.... (Score:1)
Low power PDA type devices? (Score:1)
Something usable like that would be so casual, I can only see it gaining huge acceptance by everyone... think a day-planner type book, where you can interact with it almost the same, but it's also a PDA and a E-Book reader, and a place to jot notes all at the same time, perpetually powered by a solar-charged battery. Awesome.
So (Score:1)
Re:Sick Editors (Score:1)
When Windows dies... (Score:2)
Re:A few bits from an insider. (Score:1)
1. How does this perovskovite material differ from that used previously by Motorola (see reference here [motorola.com])?
2. What will be the primary limitation for bringing this technology into a manufacturable process and how far off in the future is this?
Thanks.
Re:Motorolla makes a play for this tech? (Score:1)
Motorola is the #1 supplier of chips to the the communications industry, makes processors for Macs as well as Palm Pilots and licenses a lot of its process technology, such as copper interconnects and SOI, to AMD, so don't worry this technology is not likely to get lost in the shuffle.
Quantum interference.... (Score:1)
Re:Other ramifications (Score:1)
Okay, I'll go quietly...
Perv-y Material Heralds Move From Silicon (Score:2)
Screw 3...
Re:Motorolla makes a play for this tech? (Score:1)
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Re:When Windows dies... (Score:1)
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Re:Well, sort-of (Score:1)
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Re:Other ramifications (Score:1)
cool (Score:1)
I've always been a bit cheesed off at the fact that turning on the box takes a good 3 minutes or so (yes, I'm a lame M$ user, although it's pretty much under protest), so I usually go to the loo, grab a glass of water, or do some other quick activity between hitting on and getting prompted for my password, and again between punching in my password and having windows finish loading up. having computers boot up immediately from the word go would be a great step in the right direction. It would also force microsoft to rethink their entire "reboot every time you touch your system" mechanism.
My question is: does anyone know about any drawbacks to using this pervy oxide as opposed to silicon dioxide? If this perv-suchandsuch oxide turns out to be worth its salt, we'll all end up wasting a lot less time whenever we want to use our computers...
Re:Well, sort-of (Score:1)
Improvement in malability (Score:2)
One of the potential advantages of this include being able to "print" the circuit while it's flat, then "corrogate" the results making a chip with a larger surface area in a small space, both miniturising the area needed on a circuit board to support the chip, and making heat transfer away from the chip more efficient.
Another is that the technology can be used on chips where the environment would naturally be flexible, which in some industrial strength situations is a necessity.
Exciting stuff indeed!
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Re:Celibacy (Score:1)
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Re:Other ramifications (Score:1)