First 3D Nanotube and RRAM ICs Come Out of Foundry

Skywater Technology Foundry produces first wafers in a drive to match performance of cutting-edge silicon chips

Here’s something you don’t see very often at government-sponsored technology meetings—spontaneous applause. It happened at DARPA’s Electronics Resurgence Initiative Summit this week when MIT assistant professor Max Shulaker held up a silicon wafer that is the first step in proving DARPA’s plan to turn a trailing edge foundry into something that can produce chips that can compete—even in a limited sense—with the world’s leading edge foundries.

“This wafer was made just last Friday… and it’s the first monolithic 3D IC ever fabricated within a foundry,” he told the crowd of several hundred engineers Tuesday in Detroit. On the wafer were multiple chips made of a layer of CMOS carbon nanotube transistors and a layer of RRAM memory cells built atop one another and linked together vertically with a dense array of connectors called vias. The idea behind the DARPA-funded project, called 3DSoC, is that chips made with multiple layers of both would have a 50-fold performance advantage over today’s 7-nanometer chips. That’s especially ambitious given that the lithographic process the new chips are based on (the 90-nanometer node) was last cutting-edge back in 2004.