Intel's Breakthrough in RibbonFET Transistor Scaling Demonstrates Silicon Viability for Future Nodes

For the latest insights from the 2024 IEEE International Electron Devices Meeting (IEDM), including groundbreaking advancements in 2nm CMOS logic, extremely scaled transistors, monolithic CFET inverters, energy-efficient 3D computing-in-memory, and novel device technologies, you can explore the full press kit here.

Extremely Scaled Transistors from Intel: Intel researchers will show that silicon can continue to support the extreme gate length scaling which future technology nodes require. They will describe how they built RibbonFET CMOS transistors (Intel’s version of nanosheets) with 6nm gate lengths at 45nm contacted poly pitch (CPP, the spacing between adjacent transistor gates), with no degradation of electron mobility (how fast electrons can move through a material). The researchers will show that electron mobility doesn’t degrade until 3nm Tsi (silicon thickness), below which electron scattering due to surface roughness becomes an issue. They will describe how they achieved good short channel control (≤100mV/V at <4nm Tsi), with extremely low threshold voltage at these gate lengths through clever workfunction engineering. The work shows that 3nm is a practical scaling limit for RibbonFETs.

The image illustrates the behavior of drain-induced barrier lowering (DIBL) vs. silicon thickness (Tsi) at LG=18nm. It shows a reduction as Tsi is scaled from 10nm to 1.5nm; however, DIBL reduction saturates at Tsi <4nm, below which very little gain is obtained. PMOS DIBL is elevated vs. NMOS DIBL at the same Tsi. Also shown are TEM micrographs of a 1NR transistor with various Tsi values down to 1.5nm.

The series of images are (a) TEM micrograph and EDX scan of a completed 6nm RibbonFET device on a 1NR vehicle, showing a disconnected subfin; (b - d) are high-resolution cross-section TEMs for Tsi=5.5nm, 3.1nm and 1.7nm respectively, at 6nm gate length on a 1NR vehicle

Sources:

IEDM 2024 Press Kit Paper #2.2, “Silicon RibbonFET CMOS at 6nm Gate Length,” A. Agrawal et al, Intel https://www.ieee-iedm.org/press-kit