Low-Temp 2D Semiconductors: A Chipmaking Shift

Summary

Chipmaking giants like Intel, Samsung, and TSMC see a future where key parts of silicon transistors are replaced with semiconductors that are only a few atoms thick. Although they’ve reported progress toward that goal, that future is generally thought to be more than a decade away. Now, a startup spun out of MIT thinks it has cracked the code for making commercial-scale 2D semiconductors and expects chipmakers to have integrated them in advanced chips in half that time.CDimension has developed a process for growing molybdenum disulfide (MoS2), a 2D semiconductor, on silicon at a low enough temperature that it will not damage underlying silicon circuits. That could allow the integration of layers of 2D transistors above existing silicon circuits and eventually multitiered 3D chips made from 2D devices.“A lot of people think of 2D semiconductors as something that’s still in the laboratory,” says CDimension CEO and co-founder Jiadi Zhu. “But CDimension has a proprietary tool designed for 2D material growth…and we’ve addressed a lot of critical [2D materials] problems regarding wafer-scale uniformity, regarding device performance and variation, regarding device reliability, and regarding compatibility with silicon manufacturing processes.” Taken together, 2D semiconductors are ready to enter an industrial phase of development, he says. Much of CDimension’s plans hinge on a proprietary process that it uses to grow a single layer of MoS2 on silicon and other substrates at only about 200 °C across entire 300-millimeter wafers. 2D materials are formed by chemical vapor deposition, wherein vaporized precursor chemicals react on a surface to coat it. But typically the reactions for making 2D materials requires temperatures upward of 1,000 °C. That’s so high it would damage any underlying structures needed to make transistors. Today, researchers get around that problem by depositing the 2D semiconductor separately and then delicately transferring it to a silicon wafer. But CDi...