Glossary / Semiconductors
Gate-all-around
A transistor structure in which the channel is a stack of thin sheets (nanosheets), each fully surrounded by the gate on all sides.
A FinFET grips its channel on three sides but leaves the bottom open. Gate-all-around (GAA) lays the channel down as thin sheets stacked on top of each other and wraps the gate completely around each one. In 2017 a team from IBM and partners showed that stacked nanosheets could carry scaling beyond the FinFET[1].
Samsung adopted it for 3 nm production in 2022 and TSMC for 2 nm in 2025. It suppresses leakage and lets designers trade performance against power by varying sheet width, but manufacturing is more complex again, which makes yield harder to raise.
Related terms
- FinFETA three-dimensional transistor in which the channel stands up like a fish's fin and the gate wraps around it on three sides.
- MOS transistorA transistor built from a metal electrode, an oxide layer and a semiconductor, in which a voltage on the electrode alone opens and closes the channel. Most of today's chips are made of these.
- YieldThe fraction of manufactured products that work. In semiconductors, the share of good chips obtained from a wafer.