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[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.

[More to come ...]

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