Black Phosphorus Could Spur the Next Wave of Tiny Transistors 35
Zothecula writes: Researchers at McGill University and Université de Montréal have provided insight into another promising candidate that could help chip designers keep pace with Moore's Law: black phosphorus — a stable form of the element that can be separated into individual atomic layers, known as phosphorene (abstract). "Phosphorene has sparked growing interest because it overcomes many of the challenges of using graphene in electronics. Unlike graphene, which acts like a metal, black phosphorus is a natural semiconductor: it can be readily switched on and off." This new research found that "electrons are able to be pulled into a sheet of charge which is two-dimensional, even though they occupy a volume that is several atomic layers in thickness." It's an important step toward developing a manufacturing process for transistors made of this material.
Re: Graphene (Score:1)
Yikes. I reread he summary. Sorry. My brain is fried.
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It's okay - some of us doesn't have one at all.
Comparison (Score:2)
"All the ease of use of graphene, plus the flammability of matches!"
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I came here to ask that very question ... according to this [ucdavis.edu]:
But I have no idea what "most stable" means in a relative sense.
I don't think of graphite as being something which bursts into flames, so maybe it's not so far fetched.
Vaporware? (Score:2)
Hopefully this won't be like promising new battery tech that's always 5-10 years away. Assuming black phosphoros turns out to be a viable material, how long would it take until chips made with such transistors are actually mass-produced?
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Hopefully this won't be like promising new battery tech that's always 5-10 years away.
Batteries have been steadily improving by about 5% per year. That is good, solid progress. Moore's Law applies to semiconductors, and only semiconductors. Only a tiny handful of other technologies (HDD density, gene sequencing) have been improving at anywhere close to a Moore's law rate.
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Batteries have been steadily improving by about 5% per year.
Yea, but /. is big on reporting "new technologies" that are going to give us 100% jumps in improvement in "one or two years". They do this on a regular basis with batteries, no matter if it is a nano-material electrode with vastly greater surface area or some other change. And the articles and summaries usually go to great lengths to point out how easily the new technology will integrate into current production techniques. This has been going
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we never see the great factor of two or even factor of ten improvements promised
Yes we do. Go look at a cell phone battery from the 1990s, and compare it to a modern battery, that is half the size with twice the capacity. There has been a huge improvement. Just because you are oblivious to progress, doesn't mean it isn't happening.
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My statement is that we never see the 100% to 1000% percent jump in capacity promised from a single innovation in one step in a year or two after the announcement.
Part of becoming an adult, is realizing that profound progress (which is happening) doesn't happen with the wave of a fairy godmother's wand. In the past two decades, batteries have improved by 200-400%. That is fantastic progress. I am sorry that you are disappointed that it wasn't compressed into "one step", as you were "promised".
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Well, part of becoming old and cynical is that we often get told we'll see profound progress "real soon now" ... usually in 5-10 years, and which doesn't actually happen.
Yay, progress! We're all in favor of it. But if every breakthrough I've seen on Slashdot which was meant to revolutionize things in 5-10 years had come true ... batteries would be a zillion times faster, CPUs would be infinitely fast, and we'd actually have flying frickin' cars.
I personally am not upset we didn't get the giant one step.
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And part of being even older than you, is to realize that promising revolutions is just a human way of saying: I've achieved something. And then we shake our weary, old heads, and we applaud the youngster for his work. And then it's nap time.
Melting Point Could be an Issue (Score:2)
According to PTable.com [ptable.com] elemental phosphorus has a melting point of 317 K, around 44 C. My laptop currently has multiple parts hotter than 40 C, so this will require a fair bit of work to get anything stable out of it.
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black and red phosphorus have melting point of 590 degrees C.
A concern for those running black phosphorus Itanium3's in their laptop
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What does the melting point of an element have to do with structures formed from atoms of that element? The melting point of black phosphorus is 590 C.
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What does the melting point of an element have to do with structures formed from atoms of that element?
Since a phase change is also a structural change, I'd say "everything".
However, as you say, the black allotrope has a very high melting point. It's only the white/yellow allotrope that's low-melting.
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I meant to write what does the melting point of an element have to do with the melting point of structures formed from atoms of that element, but somehow left out the second "melting point".
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Ptable.com isn't telling you everything you need to know. The melting point it lists is for the white (yellow) allotrope, the one that spontaneously combusts in air. The red and black allotropes are a lot more refractory, and a lot less chemically reactive.
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Black phosphorous 'monolayer' flakes oxidize in air within seconds.
That results in P2O5, at the least. In air, due to humidity, it ultimately results in H3PO4 – phosphoric acid.
Not a friendly chemical.
Lots of options (Score:3)
Now that they can extract pure silicon 28 with a simple linear accelerator (which should have been obvious), it should be possible to use much larger dies without running into imperfection problems. That doesn't keep to Moore's Law, admittedly, but it does mean you can halve the space that double the transistors would take, since you're eliminating a lot of packaging. Over the space of the motherboard, it would more than work out, especially if they moved to wafer-scale integration. Want to know how many cores they put onto a wafer using regular dies? Instead of chopping the wafer up, you throw on interconnects Transputer-style.
Graphene is troublesome, yes, but there's lots of places you need regular conductors. If you replace copper interconnects and the gold links to the pins, you should be able to reduce the heat generated and therefore increase the speed you can run the chips. Graphene might also help with 3D chip technology, as you're going to be generating less heat between the layers. That would let you double the number of transistors per unit area occupied, even if not per unit area utilized.
Gallium Arsenide is still an option. If you can sort pure isotopes then it may be possible to overcome many of the limitations that have existed so far on the technology. It has been nasty to utilize, due to pollution, but we're well into the age where you can just convert the pollution into plasma and again separate out what's in it. It might be a little expensive, but the cost of cleanup will always be more and you can sell the results from the separation. It's much harder to sell polluted mud.
In the end, because people want compute power rather than a specific transistor count, Processor-in-Memory is always an option, simply move logic into RAM and avoid having to perform those functions by going through support chips, a bus and all the layers of a CPU in order to get carried out. DDR4 is nice and all that, but main memory is still a slow part of the system and the caches on the CPU are easily flooded due to code always expanding to the space available. There is also far too much work going on in managing memory. The current Linux memory manager is probably one of the best around. Take that and all the memory support chips, put it on an oversized ASIC and give it some cache. The POWER8 processor has 96 megabytes of L3 cache. I hate odd amounts and the memory logic won't be nearly as complex as the POWER8's, so let's increase it to 128 megabytes. Since the cache will be running at close to the speed of the CPU, exhaustion and stalling won't be nearly so common.
Actually, the best thing would be for the IMF (since it's not doing anything useful with its money) to buy millions of POWER8 and MIPS64 processors, offering them for free to geeks individually on on daughter boards that can be plugged in as expansion cards. At worst, it would make life very interesting.
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Yield has more factors than odd isotopes of silicon. It will not be possible to use larger dies without running into some other yield problem.
Carbon nanotubes are good conductors also.
Gallium Arsenide is under development currently for 7nm.
Stacking dram on top of CPU die is being done currently. With CPU and ram in the same package on an MP board you have processor-in-memory systems available right now, with the added benefit that if you spill out of in package ram you use board level ram. Virtual memory
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Carbon nanotubes can be either conductors, insulators, or both (depending on direction).
If you're going into 3-D construction, what you need are superconductors of heat to embed into the chip with connections to outside. (Yeah, reducing internal resistance also helps.) Interestingly, most superconductors of electricity are also superconductors of heat...so what you need are high temperature superconductors, where high temperature means something around 100C. I've seen claims that graphene is a supercondu
Heat superconductors? (Score:3)
I'm very sorry, but Larry Niven lied to us in Ringworld.
Electrical superconductors are not heat superconductors; in fact, as far as I know, nobody has demonstrated true heat superconductivity (all points of the material remain at the same temperature, supporting infinite heat-transfer rates). I found a speculative paper about it from 2012, but it's only speculation.
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Mmmph. Ok, I need to rethink that. But some liquid Helium *is* a superconductor of heat (I'm not sure that true of all allotropes). So perhaps there are others.
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Yep, Niven blew that one.
Heat pipes come close but have power density limits based on evaporative area and transport so they scale downward poorly. They already require heat spreaders to cool existing high performance ICs.
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Instead of chopping the wafer up, you throw on interconnects Transputer-style.
Well, that reference just made my day!
Relevant: homemade memristor (Score:2)
Rock band! (Score:1)
everything old is new again (Score:3)
We're working our way back to the 2D electron gas work done in the decades before graphene.
Phosphorene is not a true 2D material (this is a "few layer" material, it's not a perfect analog of graphene), yet electrons in phosphorene can be made to behave as if they're in perfect 2D confinement. This is not the only material you can do this with. There are many ways of creating a 2D electron gas, with a wide range of applications and properties. There are some old hands at making these structures in the nano community, don't be surprised if in the next couple of years much is made in the academic literature of GaAs and GaN (again).