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First Exciton Integrated Circuit Built

Exciton ICs would negate the need to convert optical data to electrons and back again

2 min read

20 June 2008—Researchers at the University of California, San Diego, say they’ve made an experimental integrated circuit that operates using excitons—basically energized electrons bound to positively charged counterparts called holes, which form when light hits a semiconductor. The group’s results were detailed 19 June in the online version of Science . If the technology could be commercialized, it could speed computing and communications by better integrating electronic circuits and optical data communications.

Computers process signals using electrons, but most data communication outside the computer happens via photons. Because light cannot be easily manipulated with electric fields, the light signals are usually first converted to electrical signals by a photodiode, processed in the computer, and then converted to light again using a laser and other optical components for transport—an inefficient scheme. Excitons, however, directly interact with electric fields, eliminating the need for all the conversion steps and making for potentially faster and more energy-efficient computing.

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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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