GAA and CFET
- [University of California, Berkeley - Sing Lin]
- Overview
Gate-All-Around (GAA) and Complementary FET (CFET) are transistor technologies. GAA is a transistor architecture that uses a horizontal channel instead of a vertical one. CFET is a more complex version of a gate-all-around device.
GAA Technology:
- GAA is similar to a FinFET transistor, but the gate material surrounds the channel from all sides.
- GAA takes the FinFET design and turns it sideways so that the channels are horizontal instead of vertical.
GAA has several advantages, including:
- Better gate controllability
- Almost negligible leakage current
- Very little effect of short channel
- High drain current
- Low subthreshold slope
- Very little corner effect
CFET Technology:
- CFET is slated for 2.5nm and beyond.
- CFET will power the next generation of silicon-based devices.
- Intel has announced that it will use stacked CFET transistors in the future.
- GAA Technology
Gate-all-around (GAA) technology is a semiconductor manufacturing process that uses transistors with a gate that can contact the channel on all sides.
GAA technology is also known as gate-all-around field-effect transistor (GAA-FET) technology.
GAA technology overcomes the limitations of FinFET technology by:
- Reduces the supply voltage level
- Enhances performance with a boost in drive current capability
- Makes continuous scaling possible
- Employs nanowire or stacked nanosheet technology
- Uses a silicon-on-insulator (SOI) substrate
- Enables high-performance and low-operating power designs
GAA technology is an upgraded transistor structure that uses a silicon nanowire with a gate going around it. The gate can come into contact with the channel on all sides.
GAA technology was first demonstrated in 1988 by a Toshiba research team. In mid-2022, Samsung started shipping its 3 nm gate all around (GAA) process, named 3GAA.
GAA technology defies the performance limitations of FinFET. FinFET is a type of non-planar transistor, or "3D" transistor. It is the basis for modern nanoelectronic semiconductor device fabrication.
- Complementary FET (CFET) Technology
Complementary FET (CFET) is a semiconductor technology that is slated for 2.5nm and beyond. It is a more complex version of a gate-all-around device.
CFET has several advantages, including:
- The ability to design standard cells with fewer metal tracks
- Lower drive current than FinFET by 26% and 45% respectively
- Lower iso-power frequency by 20%
CFET is an attractive device architecture for beyond 1nm logic technology nodes. It will power the next generation of silicon-based devices.
Intel and TSMC are both reporting on next-gen CFET transistor progress. TSMC is focused on the monolithic CFET process technology.
