First truly 3D chip fabbed at US foundry, features carbon nanotube transistors and RAM on a single die — future devices could have up to 1000x improvement in energy-delay product

A collaborative research team has demonstrated what it says is the first monolithic 3D integrated circuit manufactured at a commercial U.S. foundry, reporting substantial performance gains over conventional flat chip designs. The prototype was developed by engineers from Stanford, Carnegie Mellon, the University of Pennsylvania, and MIT, and fabricated in partnership with SkyWater Technology.

The chip departs from conventional two-dimensional layouts by stacking memory and logic directly on top of one…