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Harvard Team Makes Programmable Logic from Nanowires

Nanowires made into logic tiles could be basis of low-power nanoprocessors

3 min read

9 February 2011—Transistors made from silicon-clad germanium nanowires—much smaller than traditional transistors—have for the first time been built into programmable "logic tiles," say researchers at Harvard University. Such tiles, layered together, could be the foundation for miniature processors that could control microrobots or run implantable medical monitors.

Professor Charles Lieber and his colleagues demonstrated silicon/germanium nanowire field-effect transistors (FETs) back in 2006; they were only 18 nanometers across and outperformed ordinary silicon FETs. But they were hard to manufacture with any consistency. "Researchers like myself like to say how good they are, but they just haven’t been reproducible enough to assemble into larger circuits," Lieber says.

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3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

10 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

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