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Cheap Metal-Insulator-Metal (MiM) Diode Created 137

Posted by Soulskill
from the technological-increment dept.
An anonymous reader writes "Progress on metal-insulator-metal diode manufacturing was just reported online in the professional journal Advanced Materials (abstract). For the first time a high-performance 'metal-insulator-metal' diode was created with cheap materials. This is a fundamental discovery. It could change the way manufacturers produce electronic products at high speed, on a huge scale, and at a very low cost, even less than with conventional methods."
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Cheap Metal-Insulator-Metal (MiM) Diode Created

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  • by Anonymous Coward on Saturday October 30, 2010 @10:14PM (#34077146)
    A complete gamechanger, just like memristors!
    • Whatever happened to memristors?

      • Re: (Score:1, Funny)

        by Anonymous Coward
        I forget.
        • Re: (Score:1, Funny)

          by Anonymous Coward

          Oh, I remember! It was a- that is, the thing is a big--

          Hmm. I guess I forget too.

      • Like with every breakthrough, it'll take atleast 50 years to reach consumers.
        • Re: (Score:2, Interesting)

          by davester666 (731373)

          And even though everything about the process will be cheaper, faster and better, the 'cheaper' part will magically disappear through the use of patent fee's.

          • by DFJA (680282)

            the 'cheaper' part will magically disappear through the use of patent fee's.

            I find it usually disappears as a result of the misuse of apostrophe's.

        • I guess that must be why there were no transistors in consumer products until the late 1990s.

        • by Kvasio (127200)

          Like with every breakthrough, it'll take atleast 50 years to reach consumers.

          as wiki timeline suggests [wikipedia.org], the time is up ....

      • Re: (Score:3, Informative)

        by Zerth (26112)

        Whatever happened to memristors?

        HP just developed an implementation in the last year.

        It will take them a couple years to get a production line going, then a few more years before it starts showing up in products.

      • Re:Ground breaking (Score:5, Informative)

        by TopSpin (753) on Saturday October 30, 2010 @10:56PM (#34077342) Journal

        Whatever happened to memristors?

        HP has partnered with Hynix to develop the manufacturing process and commercialize memristor products. Memristors used for storage will eventually appear as ReRAM (resistive RAM.) Meanwhile, other companies are working on memristor designs based on material other than TiO2 as is used by HP.

        Would someone with a good grounding in semiconductors please elaborate on why MIM diodes are significant? I have a good handle on basic electronics but not enough experience to deduce how MIM diodes would improve circuit design.

        • I think it's that MIM is cheap, at least compared to doped silicon.
          • Re: (Score:3, Informative)

            I think you're right, and I would guess that the startup costs are much cheaper with this technology. But I wonder how useful it is when we can already print thousands transistors for pennies after the initial cost of a fab. Maybe it will allow for easier tinkering for people sitting in their garage? Would be pretty cool to build your own diode.
            • Re:Ground breaking (Score:4, Interesting)

              by blackraven14250 (902843) on Saturday October 30, 2010 @11:37PM (#34077506)
              even if it costs pennies now, the fact that it will cost a single penny later is definitely a step forward. That is especially true if the silicon supply is less abundant (not likely), or less easy to mine (possible), than the supply of the metals and insulators used here. That would mean a greater rise in the price of silicon over a given time frame than the price of the metal/insulator.
              • Re:Ground breaking (Score:5, Insightful)

                by kurokame (1764228) on Sunday October 31, 2010 @12:13AM (#34077630)

                Silicon is not something we're going to run out of in the foreseeable future. If we do, it would probably be right after we ran out of nitrogen.

                • Re: (Score:2, Insightful)

                  It's not a matter us running out. If the supply of silicon is harder to mine and purify than the metal/insulator (whichever is harder) necessary for the new technology, then the new tech is an economic improvement.
                  • Re:Ground breaking (Score:5, Insightful)

                    by kurokame (1764228) on Sunday October 31, 2010 @12:59AM (#34077764)

                    The insulator is generally treated silicon, e.g. silicon nitride.

                    Also, metals are something you find pockets of in the Earth's crust. The majority ended up in the core by virtue of its greater density. Silicon, on the other hand, is a key ingredient in the crust itself, and tends to be present in the minerals which you would have to find, extract, and process to get the metals involved in circuit-on-silicon fabrication.

                    Also, the amount of material in the silicon wafer itself is far, far more than the entirety of all surface features comprising the integrated circuit.

                    If anything, you would want to be comparing the relative scarcity or value of the metals involved versus the dopants involved, the relative ease of fabrication, and the particulars of what you can fabricate like minimum feature size, chip area per circuit element, and compatibility with other things you want to do on your wafer.

                  • Silicon is like 70% of earths crust. If we have run out of it, we have run out of earths crust. Beaches would be mined for their sand, dirt would all be gone. I mean literally, you don't know how ridiculous that notion sounds.

                    • by baegucb (18706)

                      Most references I've seen say it's 25-27% of the crust (still alot).

                    • right, i was thinking silicon oxide, which is about 60 percent. But yea, either way, if we run out we will have bigger problems than running out of silicon.

              • by X0563511 (793323)

                It's not the silicon that's the worry, it's the other materials that are doped in that makes it expensive, dangerous, or 'rare'.

              • of silicon.

                We would have to run out of gravel, sand, rock, pebbles, stones and dirt first.

          • Re:Ground breaking (Score:5, Informative)

            by John Hasler (414242) on Sunday October 31, 2010 @08:06AM (#34078856) Homepage
            No. It's that MiMs are fast. The best junction diodes run out of steam at a few THz while MiMs work up into optical frequencies and so can be used to rectify sunlight. MiMs have been made before and are used in some exotic lab equipment but those point-contact devices are hard to make and touchy. These guys claim to have produced MiMs using more or less standard planar processes.

            Here's a paper [colorado.edu] that explains MiM theory, though it isn't about this development.
            • Are you referring to "point-contact devices" as in working on similar principles to cat's whisker or crystal-crystal rectifiers? Are we talking going back to the really nice clear and low-power function of pre-transistor devices, but with reliability and economies of scale those devices never achieved?

              • Are you referring to "point-contact devices" as in working on similar principles to cat's whisker or crystal-crystal rectifiers?

                No.

                Are we talking going back to the really nice clear and low-power function of pre-transistor devices, but with reliability and economies of scale those devices never achieved?

                No.

                • Well, then, could you please point to a decent reference where I could educate myself about what you do mean?

                • I read the first 35 pages of that thesis so far, and it reads as if, yes, this is an attempt to manufacture a reliable metal oxide point-contact rectifier on a plane to be used in much the same way as the old unreliable iron pyrite crystal radio diodes. Please, if I'm wrong, point me to a correction. Your simple, "No. No." is not at all helpful to point out the differences.

                  • Metal oxide is not an insulator, it's a semiconductor ... using metal oxides is pretty common already, you might recognize the term MOS. The difference is the use of an insulator instead of a semiconductor.

                    • So the difference is in using tunneling through an insulator in some instances and not others rather than conducting through the semiconductor in some instances and not others?

                    • Metal oxide is not an insulator, it's a semiconductor ...

                      Many metal oxides are insulators.

                      ... using metal oxides is pretty common already, you might recognize the term MOS.

                      MOS stands for "Metal-Oxide-Semiconductor". The metal is usually aluminum, the oxide silicon dioxide (an insulator), and the semiconductor silicon.

                • by whit3 (318913)

                  Are you referring to "point-contact devices" as in working on similar principles to cat's whisker or crystal-crystal rectifiers?

                  No.

                  Actually, I'd say yes here. The previous technology was
                  a gizmo called a 'coherer' which was basically a bottle of metal
                  granules. If it stopped rectifying, ya had to shake the bottle.
                  That technology goes back nearly a century.

            • Re: (Score:3, Informative)

              by camperslo (704715)

              It's a bit surprising to find out that some relatively unknown experimenters may have actually stumbled on tunnel-diode-like technology in the early days of radio over 80 years ago. I think they were officially invented by Sony in 1957, although most that I've seen in the U.S. came from G.E.
              http://www.sony.co.jp/Products/SC-HP/outline/overview/history.html [sony.co.jp]

              Perhaps some here have experimented with a homemade cat-whisker diode for a crystal radio.
              As it turns out, making a little oscillator with a homemade met

        • Re:Ground breaking (Score:5, Interesting)

          by kurokame (1764228) on Sunday October 31, 2010 @12:11AM (#34077622)

          Mainly, most immediately, it gives you an additional way to make a diode or diode-based structure when you're designing your fabrication sequence. Fabrication on the foundry / mass-production level occurs through processes which give you pretty much a set sequence of layers (deposited materials, treatments, patterning, etching, etc.). You can make anything you can design within that process...and most anything else usually stays in a research lab.

          The extraordinarily common CMOS process involves numerous metal layers "high" above the wafer (numerous layers intervene). These are separated by insulators. Normally, you make diodes at the wafer layer where you're doing your doping.

          MiM means you can put diodes in regions of your chip where they couldn't practically be fabricated before without a lot of time doing a one-off chip in a lab. With "a lot" often being several months to a year, assuming everything turns out perfectly, assuming your lab even HAS all the necessary equipment, and assuming you don't have something better to do - which is rare if you're not still a grad student.

          • Re: (Score:3, Interesting)

            This might be true, but looking at the thesis linked below the main target seems large area/feature size devices devices such as TFT display backplanes and drivers.

            • Displays? Meh. (Score:4, Interesting)

              by John Hasler (414242) on Sunday October 31, 2010 @09:44AM (#34079334) Homepage

              That may be where the money is but the interesting applications are elsewhere. For example, MiMs could be useful as mixers and detectors all the way up to the visible. If they can be fabricated with a negative-resistance region they could serve as oscillators over the same range.

              • by kurokame (1764228)
                Money means production, production means process integration, process integration means it's available to anyone making a foundry order. Less interesting but profitable applications work fine for me.
        • by Kvasio (127200)

          Would someone with a good grounding in semiconductors please elaborate on why MIM diodes are significant?

          because some day rare elements that you need might be not available in your area code [slashdot.org] or too expensive?

        • Would someone with a good grounding in semiconductors please elaborate on why MIM diodes are significant? I have a good handle on basic electronics but not enough experience to deduce how MIM diodes would improve circuit design.

          The article said one of the advantages of this is that it is faster than silicon technology. Instead of an electron having to travel through silicon in the normal way, with an MIM the electron "tunnels" through the middle layer and reaches the opposite metal side almost instantaneously. While the cost savings will be nice, the speed is the main advantage inside circuits.

  • I really hate this kind of thing... a potentially useful technology for building electronics devices at home, and it's behind a paywall.
    • I wouldnt pass judgement without knowing how much they spent on developing it.

      • In every case, either they'll be stinking rich or we'll never hear of this technology again.
        • If they're rich, it's because it was a very important development and they were rewarded for taking the time and energy to make it useful. If we never see it again either it wasn't really all that important or somebody, in an effort to get around a patent, came up with an even better approach.

          Any way you slice it, it's good.

    • by WarJolt (990309) on Saturday October 30, 2010 @10:28PM (#34077214)

      Everyone wants information to be free... Until they come up with an idea of their own and publish it.

      • Re: (Score:3, Insightful)

        by coldmist (154493)

        Information wants to be free. People want to control it and hide it and charge for it. But, if I told you a secret, you naturally want to share it. If I write a book, and people read it, that information is now theirs too, ie "free".

        Of course people want free information. But, some people keep it in chains and lock it up and prevent it from becoming "public" knowledge, for their own personal gain. It's a war that has been waged for ever and will continue to rage...

      • by martin-boundary (547041) on Saturday October 30, 2010 @11:20PM (#34077450)
        What are you smoking? Sounds yummy.

        Just about every scientist who's employed in a university wants to give away their published articles for free to anyone with even a tiny interest. The only ones who like paywalls are publishers.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      the article?

      There may be a building in your neighborhood that houses paywall penetrating tools. You can even go there and use them for free. I believe your community may call this building a "Library."

      Or, if you are talking about them patenting the "invention", then yeah.. that sucks.

  • the most abundant element in the universe? Or is it cheaper somehow in terms of production process?
  • I am no Electrical Engineer, but I am sure diodes are not the only component used in electrical circuits, so how is it a fundamental breakthrough that is going to affect the overall manufacturing speed of electronic products? Moreover, From TFA

    High speed computers and electronics that don’t depend on transistors are possibilities

    Which high speed computer in use today doesn't use transistors? The only related research in transistor-less gates I can think of is QCA and magnonics, both of which are a few years away from being used in Computer manufacturing, and neither uses diodes as the base.

    • by IorDMUX (870522)

      High speed computers and electronics that don't depend on transistors are possibilities

      Which high speed computer in use today doesn't use transistors?

      I believe they meant: (High speed computers) and (electronics that don't depend on transistors) are possibilities.

      Though... I'm not really certain *how* this invention enables such things, even after reading it over.

      • well, the electrons tunnel instead of 'moving',
        one thing the article didn't touch on is that if the electrons tunnel instead of moving then entropy is good.
        so heat should be next to zero I should imagine?

        electrons tunnelling is a bit like 1+1 = 3
        the extra 1 that's missing is the work, which would create heat and slow things down.

    • I would have to agree -- you are no Electrical Engineer.
    • by MichaelSmith (789609) on Saturday October 30, 2010 @11:39PM (#34077512) Homepage Journal

      But isn't a transistor just a diode with a way to control the junction? So maybe you could position a third wire and get some gain out of it.

      • by whoever57 (658626)

        But isn't a transistor just a diode with a way to control the junction?

        Not CMOS transistors, which are the dominant type used today.

  • How does this work? (Score:5, Informative)

    by Required Snark (1702878) on Saturday October 30, 2010 @11:00PM (#34077360)
    I went and asked Mr. Google how this worked, and I couldn't find any answers. The best clue I got was that these devices use quantum tunneling, but this still does not explain how they exhibit diode behavior. Even the font of all online knowledge, Wikipedia, doesn't seem to know. Someone please post about this.

    One thing I did see is that this kind of diode can operate at 100's of THz frequencies, and that this enables nantennas. http://en.wikipedia.org/wiki/Nantenna [wikipedia.org] If these kind of MIM diodes can be made cheaply then a new cost effective class of solar power device may become feasible. So it could be a really big deal.

  • This seems like an incredibly convenient discovery considering China's new embargo of rare metal exports to Japan and the US.
    • by treeves (963993)

      Unfortunately, rare earths are not used to make diodes or semiconductors, so this doesn't help that situation.

  • "This is a fundamental discovery. It could change the way manufacturers produce electronic products at high speed, on a huge scale, and at a very low cost"

    This is a fundamental discovery. It could change the way manufacturers produce electronic products at high speed, on a huge scale, and at a very high profit. There.. fixed that for ya.

  • So, will this get the Nobel Prize in ten years or later? It does really sound like a radical idea.

  • by Bender_ (179208) on Sunday October 31, 2010 @03:22AM (#34078076) Journal

    I am a semiconductor scientist, but I completely fail to understand what this news is about. The article does nowhere mention the materials used, the device behavior, the application, the purpose or anything else.
    A MIM device as is, is a capacitor. And that is exactly what the picture is showing. When this type of capacitor is scaled to the nanometer regime it starts to get leaky due to quantum mechanical tunneling through the dielectric. The abstract mentions 'controlled quantum mechanical tunneling'... Aha, this could be what it is about. But as long as metal electrodes are involved this will only create a nonlinear resistor. Still no idea what the exact purpose is.

    Are nanoscale MIM capacitors new? No, not at all. Right now you have billions of them doing their job in your computers main memory. Depending on the vintage of your computer, these capacitors employ nanolaminates of ZrO2 and Al2O3 at a total thickness of 5 to 10 nanometers. Quantum electrical tunneling is of high relevance in these devices, since it leads to loss of stored information. So, is cheap new? A quick calculation suggests that the manufacturing cost of a single MIM device in a DRAM is approximately 10^(-10) US$.

    • They use different metals with different work functions on each side of a nanometer-scale insulating layer. MiMs have been made before using point-contact techniques but are hard to make and touchy. These guys claim to be able to make them using planar technology.

    • by GrepNut (215819) on Sunday October 31, 2010 @10:06AM (#34079424)

      I agree that the article could be a lot more informative. However, one can actually figure out quite a lot. For instance, since they call it a diode, it means the leaky capacitor you mention is asymmetric, and leaks more easily in one direction than the other. This is born out by the picture, which seems to show two layers of insulator, of different thickness, between the metal layers. And once you have electrical asymmetry, you can start building all sorts of interesting logic. But I agree they do not explain why tunneling through two layers A and B in the order "A then B" should be different from "B then A". Is it because of the direction of applied voltage, or are the insulator materials asymmetric at the molecular level, or is there some deep fact about quantum tunneling that makes it work? I would certainly have liked to see that covered.

      Second, in terms of benefits, it seems this device would be far easier, simpler and cheaper to fabricate than a normal PN diode. In a PN diode, you essentially need to arrange a metal wire, a small P-doped semiconductor region, a small N-doped semiconductor region and another metal wire. In addition, the two semiconductor regions need to be insulated from their surroundings somehow. This all requires pretty careful alignment. It looks like the MiM diodes would be self-aligning, in the sense that you could just create a pattern of vertical metal wires on one layer, then overlay the two layers of insulator, followed by a layer of horizontal metal wires. The diodes would form at the points where the wires cross, without any precise alignment being needed. And the fact that the middle layers are insulators would mean no further insulation was necessary. One could probably fabricate giant sheets of these things very cheaply.

      Finally, the fact that they can use these for rectifying infrared radiation implies they can operate many orders of magnitude faster than normal CMOS diodes.

      Googling a little also hints that MiMs are better at extracting the full energy from incident photons in photovoltaic applications, which could be a useful side benefit, allowing one to efficiently convert optical or infrared radiation into DC current with a single type of device. But I'm just guessing, an expert would need to confirm that.

      In summary, I agree this article could be a lot better. However, I have seen a lot worse, and it does seem to be alerting us to something which could turn out to be important.

  • A patent has been applied for on the new technology, university officials say. New companies, industries and high-tech jobs may ultimately emerge from this advance, they add.

    Yeah. In twenty years.

    Not saying this isn't a great invention; they deserve to earn from this (unlike software patent trolls). But the likely outcome of this system is that the technology will rot for decades until it enters the public domain.

    Example: Perpendicular recording has been around since 1976 as an idea. It was commercially imp

  • The appearance of them is as old as corroded copper wire.. What has changed is that some materials specialists have figured out how to characterize these so called "parasitic" diodes and fabricate them with predictable parameters. As others have pointed out they are quite useful as they can be fabricated in the metal layers above the doped silicon, thus removing this type of component from the die and placing it in the metallization layers where there is a lot more room.

    Now basically, as I understand it

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