MIT Engineers Grow Atomically Thin 2D Materials in Silicon Circuits

The increasing need for more powerful, faster, and more efficient computing capabilities has been met with increasingly difficult materials and engineering problems as attempts at performance scaling continue. As published on Nature, MIT engineers have developed a new silicon fabrication process that works by depositing three-atom thick, atomically thin transistors (ATTs) on top of already-existing chip circuits – essentially “growing” them into high-density, high-performance computing stacks.

The team’s novel approach looks something like additive manufacturing, and applies a highly uniform, three-atom-thick layer of 2D Transition Metal Dichalcogenide (TMD) materials across an entire 8-inch, fully fabricated silicon wafer. Each new layer of TMD enables denser integrations between the underlying chip and the added transistor stacks, improving performance with unparalleled density.

The base 2D material, molybdenum disulfide, is a flexible and transparent material that ticks all the right boxes when it comes to electrical and photonic conductivity, making it a prime candidate for building semiconductor transistors. It’s composed of a one-atom layer of molybdenum, sandwiched between two atoms of sulfide.

That’s all that’s required to fabricate a modern transistor: three atoms.

That’s the point at which the scaling benefits really start to show, as according to Jiadi Zhu, an electrical engineering and computer science graduate student and co-lead author of the paper on this new technique. “Using 2D materials is a powerful way to increase the density of an integrated circuit. What we are doing is like constructing a multistory building. If you have only one floor, which is the conventional case, it won’t hold many people,” Zhu told MIT News. “But with more floors," he added "the building will hold more people that can enable amazing new things. Thanks to the heterogenous integration we are working on, we have silicon as the first floor and then we can have many floors of 2D materials directly integrated on top.”

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Francisco Pires
Freelance News Writer

Francisco Pires is a freelance news writer for Tom's Hardware with a soft side for quantum computing.