Researchers Prove Existence of New Basic Element for Electronic Circuits -- 'Memristor'

Apr 30, 2008
Researchers Prove Existence of New Basic Element for Electronic Circuits -- 'Memristor'
17 memristors in a row are visible on this AFM image. The memristor consists of two titanium dioxide layers connected to wires. When a current is applied to one, the resistance of the other changes. That change can be registered as data. Image credit: J.J. Yang / HP Labs

HP today announced that researchers from HP Labs have proven the existence of what had previously been only theorized as the fourth fundamental circuit element in electrical engineering.

This scientific advancement could make it possible to develop computer systems that have memories that do not forget, do not need to be booted up, consume far less power and associate information in a manner similar to that of the human brain.

In a paper published in today’s edition of Nature, four researchers at HP Labs’ Information and Quantum Systems Lab, led by R. Stanley Williams, presented the mathematical model and a physical example of a “memristor” – a blend of “memory resistor” – which has the unique property of retaining a history of the information it has acquired.

Leon Chua, a distinguished faculty member in the Electrical Engineering and Computer Sciences Department of the University of California at Berkeley, initially theorized about and named the element in an academic paper published 37 years ago. Chua argued that the memristor was the fourth fundamental circuit element, along with the resistor, capacitor and inductor, and that it had properties that could not be duplicated by any combination of the other three elements.

Building on their groundbreaking research in nanoelectronics, Williams and team are the first to prove the existence of the memristor.

“To find something new and yet so fundamental in the mature field of electrical engineering is a big surprise, and one that has significant implications for the future of computer science,” said Williams. “By providing a mathematical model for the physics of a memristor, HP Labs has made it possible for engineers to develop integrated circuit designs that could dramatically improve the performance and energy efficiency of PCs and data centers.”

One application for this research could be the development of a new kind of computer memory that would supplement and eventually replace today’s commonly used dynamic random access memory (DRAM). Computers using conventional DRAM lack the ability to retain information once they lose power. When power is restored to a DRAM-based computer, a slow, energy-consuming “boot-up” process is necessary to retrieve data from a magnetic disk required to run the system.

In contrast, a memristor-based computer would retain its information after losing power and would not require the boot-up process, resulting in the consumption of less power and wasted time.

This functionality could play a significant role as “cloud computing” becomes more prevalent. Cloud computing requires an IT infrastructure of hundreds of thousands of servers and storage systems. The memory and storage systems used by today’s cloud infrastructure require significant power to store, retrieve and protect the information of millions of web users worldwide.

Memristor-based memory and storage has the potential to lower power consumption and provide greater resiliency and reliability in the face of power interruptions to a data center.
Another potential application of memristor technology could be the development of computer systems that remember and associate series of events in a manner similar to the way a human brain recognizes patterns. This could substantially improve today’s facial recognition technology, enable security and privacy features that recognize a complex set of biometric features of an authorized person to access personal information, or enable an appliance to learn from experience.

Williams is the founding director of HP Labs’ Information and Quantum Systems Lab, which is focused on turning fundamental advances in areas of mathematics and physical science into technologies useful for HP. For the past 12 years, Williams and his team have conducted primary scientific research into the fundamental limits of information and computing, which has led to a series of breakthrough discoveries in nanoelectronics and nanophotonics.

More information is available at www.hpl.hp.com/research/quantum_systems.html .

Source: HP

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User comments : 27

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h0dges
4 / 5 (5) Apr 30, 2008
Neat.
thales
2.2 / 5 (6) Apr 30, 2008
Sweet, now we can start work on the Flux Memristor.
freemind
4 / 5 (4) Apr 30, 2008
I'm impressed, thanks for cool news
zevkirsh
2 / 5 (5) Apr 30, 2008
this sounds about as revolutionary as segue.
Arikin
4 / 5 (5) Apr 30, 2008
If this becomes cheap enough one could load the computer's OS into one set of these. Then use another set to hold the running applications and their data. The disk drives would be more for backup than constant use. Imagine not waiting to boot up your computer, just turn it on like a switch. Also, less data loss because the battery died or the cord was pulled.
out7x
2 / 5 (2) May 01, 2008
Explain the difference with flash memory.
Soylent
3.3 / 5 (3) May 01, 2008
Explain the difference with flash memory.


From the point of view of a user memristors could achieve greater density than harddrives and greater speed than flash or harddrives. It cannot compete with DRAM for speed.

Manufacturing cost and reliability is perhaps known to HP but not to the public.
slight_hickup
4 / 5 (4) May 01, 2008
Explain the difference with flash memory.


From the point of view of a user memristors could achieve greated density than harddrives and greater speed than flash or harddrives. It cannot compete with DRAM for speed.


Actually, it operates at around the same speed of DRAM.
Soylent
3 / 5 (3) May 01, 2008
Actually, it operates at around the same speed of DRAM.


HP states that they operate at about a tenth of the speed of a DRAM cell; I'm not about to be more optimistic than they are about their own tech.
slight_hickup
5 / 5 (1) May 01, 2008
Actually, it operates at around the same speed of DRAM.


HP states that they operate at about a tenth of the speed of a DRAM cell; I'm not about to be more optimistic than they are about their own tech.


Sorry I read that in another article that must have gotten it ever so wrong.

*tips hat in defeat*
agg
4 / 5 (4) May 01, 2008
Imagine never having to reboot your computer.
How would you solve any problems on a Windows system then?
SDMike
3 / 5 (2) May 01, 2008
Perhaps this would lead to new forms of OS. One can now blend data and OS in a more neural model.
earls
not rated yet May 01, 2008
You live up to your name slight hickup. ;p
E_L_Earnhardt
not rated yet May 01, 2008
More data, please
STAGGERBOT
4.3 / 5 (4) May 01, 2008
Explain the difference with flash memory.

According to this NYTimes article "H.P. Reports Big Advance in Memory Chip Design"
1."The Hewlett-Packard team has successfully created working circuits based on memristors that are as small as 15 nanometers (the diameter of an atom is roughly about a tenth of a nanometer.) Ultimately, it will be possible to make memristors as small as about four nanometers, Mr. Williams said. In contrast the smallest components in today%u2019s semiconductors are 45 nanometers, and the industry currently does not see a way to shrink those devices below about 20 nanometers."
and
2."Potentially even more tantalizing is the ability of the memristors to store and retrieve a vast array of intermediate values, not just the binary 1s and 0s conventional chips use. This allows them to function like biological synapses and makes them ideal for many artificial intelligence applications ranging from machine vision to understanding speech."

gongii
3.7 / 5 (6) May 01, 2008
I think this is not big news. This has been done in Japan, Korea and Taiwan years ago. It is sometimes known as RRAM, but other memories like conducting bridge RAM, MRAM, phase change memory, and FeRAM or polymer RAM will behave exactly the same, for very similar or very different reasons.

The speeds of these memories don't matter, since the wiring to access them will slow things down anyway.

I read their Nature paper and the original IEEE paper. Their discussion helps clarify the understanding, but their experimental data is still scant compared to other groups I am familiar with.
plasma_guy
3.8 / 5 (5) May 02, 2008
HP's memristor switch is very slow. 10 ms due to the ion dopant diffusion across 10 nm. This isn't replacing anything!
Star_Bound
3 / 5 (2) May 02, 2008
Google Discussion Group:
Memristor Computer Programming
http://groups.goo...gramming

You are welcome to join. Please forward the web page to others who may be interested.
STAGGERBOT
2.5 / 5 (4) May 02, 2008
I think this is not big news. This has been done in Japan, Korea and Taiwan years ago. ....
I read their Nature paper and the original IEEE paper. Their discussion helps clarify the understanding, but their experimental data is still scant compared to other groups I am familiar with.


It seems that it really is big news.
Nature's news article "Found: the missing circuit element" quotes the researcher who first proposed the idea : "Chua says that he is pleased that his theory has finally been proved. "I was very excited %u2014 I never thought I would live to see this happen."
The IEEE news article "The Mysterious Memristor: Researchers at HP have solved the 37-year mystery of the memory resistor, the missing 4th circuit element." quotes him too "Chua calls the HP work a paradigm shift; he likens the addition of the memristor to the circuit design arsenal to adding a new element to the periodic table: for one thing, %u201Cnow all the EE textbooks need to be changed,%u201D he says."

The researcher who theorized it in 1971 thinks this is big news...maybe he's not familiar with this other experimental data that you know of.

Would be cool if you had some references.



snwboardn
2.3 / 5 (3) May 02, 2008

The researcher who theorized it in 1971 thinks this is big news...maybe he's not familiar with this other experimental data that you know of.

Would be cool if you had some references.



Staggerbot that was one of the best replies. I suppose if we found a new element for the periodic table that wouldn't be significant news either. ROFL
gongii
5 / 5 (4) May 02, 2008


The researcher who theorized it in 1971 thinks this is big news...maybe he's not familiar with this other experimental data that you know of.

Would be cool if you had some references.



Professor Chua I am sure has been waiting for a physical demonstration of his results for some time. After reading the Nature Letter, I found a striking resemblance to "conducting bridge" RAM, sometimes called CBRAM. A lot of work has been done in this area by Professor Michael Kozicki. The mechanism is exactly as proposed in the letter (tug-of-war conducting portion and high-resistance portion between two electrodes) but Kozicki's work precedes this by at least a few years. At IEDM last year, Sony demonstrated a working memory array using the same concept.
gongii
5 / 5 (4) May 02, 2008
A Novel Resistance Memory with High Scalability and Nanosecond Switching

Aratani, K. Ohba, K. Mizuguchi, T. Yasuda, S. Shiimoto, T. Tsushima, T. Sone, T. Endo, K. Kouchiyama, A. Sasaki, S. Maesaka, A. Yamada, N. Narisawa, H.
Sony Corp., Atsugi

This paper appears in: Electron Devices Meeting, 2007. IEDM 2007. IEEE International
Publication Date: 10-12 Dec. 2007
On page(s): 783-786
Location: Washington, DC

Abstract
We report a novel nonvolatile dual-layered electrolytic resistance memory composed of a conductive Cu ion activated layer and a thin insulator for the first time. An ON/OFF mechanism of this new type memory is postulated as follows: Cu ions pierce through the insulator layer by applied electric field, the ions form a Cu conductive bridge in the insulator layer, and this bridge dissolves back to the ion activated layer when the field is reversed. The 4 kbit memory array with 1T-1R cell structure was fabricated based on 180 nm CMOS process. Set/reset pulses were 5 ns, 110 muA and 1 ns, 125 muA, respectively. Those conditions provide large set/reset resistance ratio of over 2 orders of magnitude and satisfactory retention. Essential characteristics for high capacity memories including superb scalability down to 20 nmphi, sufficient endurance up to 107 cycles and preliminary data for 4-level memory are also presented. These characteristics promise the memory being the next generation high capacity nonvolatile memory even before the scaling limitation of flash memories is encountered.
gongii
5 / 5 (4) May 02, 2008
From NVMTS 2003:

Electrical Characterization of Solid State Ionic Memory Elements

Ralf Symanczyk, Murali Balakrishnan, Chakravarthy Gopalan, Thomas Happ, Michael Kozicki, Thomas Mikolajick, Maria Mitkova, Mira Park, Cay-Uwe Pinnow, John Robertson, Klaus-Dieter Ufert

Abstract--Solid state ionic devices composed of metal doped glasses are among the promising new non-volatile memory technologies. The memory effect is based on polarity-dependent switching at small bias and current due to the electrodeposition of metal in the glassy electrolyte. Low voltage operation, high OFF/ON-ratios, and considerable scaling potential make this technology interesting for memory applications. In this paper, we present the results of extensive electrical characterizations from test-chips jointly processed and characterized at Arizona State University and at Infineon Technologies. The chips incorporate variations in feature size from the micrometer scale down to a hundred nanometers. The measurements address important topics for memory applications such as speed, retention, and endurance. We discuss the benefits as well as the challenges of this technology from its current stage of development.
STAGGERBOT
4.5 / 5 (4) May 02, 2008

Professor Chua I am sure has been waiting for a physical demonstration of his results for some time. After reading the Nature Letter, I found a striking resemblance to "conducting bridge" RAM, sometimes called CBRAM. A lot of work has been done in this area by Professor Michael Kozicki. The mechanism is exactly as proposed in the letter (tug-of-war conducting portion and high-resistance portion between two electrodes) but Kozicki's work precedes this by at least a few years. At IEDM last year, Sony demonstrated a working memory array using the same concept.

Good references.

I think this might sum up the situation:(from the IEEE article)
"But the smaller the scales of the devices scientists and engineers were working with got, the more the devices started behaving with the postulated %u201Cmemristor%u201D effect, says Chua, who is now a senior professor at Berkeley.
There had been clues to the memristor's existence all along." ....
%u201CWithout Chua's circuit equations, you can't make use of this device,%u201D says Williams."

It seems that once you get down small enough then the system's behavior finally gells with Chua's equations and predictions...I think that's the actual achievement with this new paper. True, the papers you referenced were using the same basic components of solid state and ionic transport for non-volatile memory that the HP team used.(striking resemblance for sure in that regard) It seems inevitable that the memristor as characterized by Chua would be created.
I guess what remains to be proven is whether or not it truly is a fundamental new type of passive component. But Chua, IEEE, Nature, and HP Labs all have reputations which I think add a great deal of weight to the claim that it is an important developement -- You make a good point though, until everyone has had time to examine the details, retaining some healthy skepticism is the way to go for such a big claim.
(Again - nice references)

gongii
not rated yet May 04, 2008


I guess what remains to be proven is whether or not it truly is a fundamental new type of passive component. But Chua, IEEE, Nature, and HP Labs all have reputations which I think add a great deal of weight to the claim that it is an important developement -- You make a good point though, until everyone has had time to examine the details, retaining some healthy skepticism is the way to go for such a big claim.
(Again - nice references)



I think there may be many more unclaimed pre-existing examples of memristance where current-dependent or charge-dependent resistance occurs, besides CBRAM. Since it is the mathematical relation that defines the memristance, it can become nearly universal, as Chua had proposed earlier. Since the connection to mainstream semiconductor application was not drawn, probably no attention was drawn at that time. But now that memory and switching applications are apparent (have been for a while), finally it is getting the deserved attention.
gongii
5 / 5 (1) May 04, 2008
A Detailed Analytical Study Of Non-Linear Semiconductor Device Modelling

Active and Passive Electronic Components Volume 18 (1995), Issue 4, Pages 211-245

Umesh Kumar
Department of Electrical Engineering, I.I. T., Havz KHAS, New Delhi 110016, India

Received 6 March 1995; Accepted 3 April 1995

Abstract

This paper presents a detailed analytical study of Gunn, SCR, and p-n junction and of the physical processes that occur inside. Based on the properties of these devices, models for Gunn, SCR, and p-n junction diode have been developed. The results of computer simulated examples have been presented in each case. The non-linear lumped model for Gunn is a unified model as it describes the diffusion effects as the-domain traves from cathode to anode. An additional feature of this model is that it describes the domain extinction and nucleation phenomena in Gunn dioder with the help of a simple timing circuit. The non-linear lumped model for SCR is general and is valid under any mode of operation in any circuit environment. The memristive circuit model for p-n junction diodes is capable of simulating realistically the diode%u2019s dynamic behavior under reverse, forward and sinusiodal operating modes. The model uses memristor, the charge-controlled resistor to mimic various second-order effects due to conductivity modulation. It is found that both storage time and fall time of the diode can be accurately predicted.
nanomvp
not rated yet May 05, 2008
With all due respect to Chua, he needed to market his idea better. At least continually follow-up for possible inadvertent demonstrations.

HP, it appears, capitalized on this marketing opportunity.

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