Three-Atom Thick Material Switches Between a Conductor and an Insulator When Tugged

Computer models build on body of knowledge of transition dichalcogenide metals

2 min read
Three-Atom Thick Material Switches Between a Conductor and an Insulator When Tugged
Tugging turns the material from a non-conducting semiconductor into a metal.
Illustration: Karel-Alexander Duerloo

As chip dimensions have decreased to match the demands of Moore’s Law, insulating materials separating the transistor gate from the channel below it have had to be thinned down so much that keeping current from leaking through has been difficult. In fact, chipmakers are no longer thinning the gate oxide, and it stands now at 1 nanometer in thickness because to go thinner would allow too much current to flow through the channel when the transistor is supposed to be turned off.

Researchers at Stanford University have been running simulations with some two-dimensional materials that when sandwiched together can switch the material between conducting and insulating just by tugging on its edges.  If physical experiments on the material are successful, it could provide a way to completely shut down the leakage of current in chips and still go to smaller chip dimensions.

The researchers believe that if the material could be used in today's smart phone processors it could reduce their power consumption considerably.

The work, which was published in the journal Nature Communications, represents a growing body of knowledge on so-called transition dichalcogenide metals, which are materials that combine one of 15 transition metals with one of three members of the chalcogen family: sulfur, selenium, or tellurium.

In the computer models, the Stanford researchers took one atomic layer of molybdenum atoms and sandwiched it between two atomic layers of tellurium atoms. In the video below, you can see the three-atom thick structure switch between conductor and an insulator as it us pulled.

It does make an attractive computer model. However, whether it can be translated into an actual physical material remains to be seen. Even if they can produce the three-atom-thick sandwich, it’s not clear whether it could really be developed for large-scale production. While physical experiments have successfully demonstrated single-atom transistors, many are questioning whether such a device could ever be be made by the millions or billions.

It’s not clear that a now three-year-old challenge of Professor Mike Kelly at Cambridge University has ever been sufficiently answered. In the challenge he argues that devices with dimensions less than three nanometers cannot be mass produced using a top-down manufacturing technique. Until that question is adequately addressed, we may have here just another computer model that could lead to a physical material but not one that could be used in the mass production of electronic devices.

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The First Million-Transistor Chip: the Engineers’ Story

Intel’s i860 RISC chip was a graphics powerhouse

21 min read
Twenty people crowd into a cubicle, the man in the center seated holding a silicon wafer full of chips

Intel's million-transistor chip development team

In San Francisco on Feb. 27, 1989, Intel Corp., Santa Clara, Calif., startled the world of high technology by presenting the first ever 1-million-transistor microprocessor, which was also the company’s first such chip to use a reduced instruction set.

The number of transistors alone marks a huge leap upward: Intel’s previous microprocessor, the 80386, has only 275,000 of them. But this long-deferred move into the booming market in reduced-instruction-set computing (RISC) was more of a shock, in part because it broke with Intel’s tradition of compatibility with earlier processors—and not least because after three well-guarded years in development the chip came as a complete surprise. Now designated the i860, it entered development in 1986 about the same time as the 80486, the yet-to-be-introduced successor to Intel’s highly regarded 80286 and 80386. The two chips have about the same area and use the same 1-micrometer CMOS technology then under development at the company’s systems production and manufacturing plant in Hillsboro, Ore. But with the i860, then code-named the N10, the company planned a revolution.

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