HP: Memristors now a reality


New insights into memristors could offer an offramp to the increasingly challenging navigations of Moore's Law scaling, and some very interesting applications in biomed research.

A memristor ("memory resistor") is the fourth fundamental circuit element (along with resistors, capacitors, and inductors), which together could form a complete set of functions in a wide variety of electronics circuits. Incorporating memristors could eliminate the need for much of the transistors & capacitors, in some cases by an order-of-magnitude, according to Stan Williams, director of HP's Information & Quantum Systems Lab and lead researcher on the project. And using fewer transistors to achieve the same functionality sidesteps the problem of maintaining Moore's Law by scaling devices to physics-altering sizes. Memristors also are seen as a potential replacement for memory chips—they are nonvolatile, consume less energy, store twice as much data in the same space, and are highly radiation-resistant.

Two years ago, HP claimed proof of existence of memristors, though some argue that it's been a popular field of study for years. And Williams teased about upcoming new achievements in memristors last November, speaking at a Silicon Valley Engineering Council event.

In a paper published in Nature (April 8, 2010), HP researchers say that they have improved their initial memristor devices so that they are closer in performance to today's silicon transistors yet at a fraction of the size—and they indeed can perform logic functions, and thus could be used in future microprocessors, made with conventional materials and processes. More immediate use would be in memory chips; HP Labs claims to have a "development-ready architectures" that stack multiple layers of memristor memory on top of each other in a single chip.

"Memristive devices could change the standard paradigm of computing by enabling calculations to be performed in the chips where data is stored rather than in a specialized central processing unit," stated Williams. "We anticipate the ability to make more compact and power-efficient computing systems well into the future, even after it is no longer possible to make transistors smaller via the traditional Moore's Law approach.

Moreover, there's a clear path to some interesting applications for memristors—whose functionality is basically the same as how a brain works. "The flood gate is now open for commercialization of computers that would compute like human brains, which is totally different from the von Neumann architecture underpinning all digital computers," added UC/Berkeley's Leon Chua, who was involved in the pioneering work in memristors in the 1970s. — J.M.

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