GAA

Overview

Gate-All-Around (GAA) is the next-generation transistor architecture succeeding FinFET, designed to continue the miniaturization and performance scaling of semiconductor chips, particularly at the 3nm node and smaller.

The core difference between GAA and FinFET is the level of control the gate has over the transistor channel:

  • FinFET: The gate wraps around three sides of the raised silicon fin (channel).
  • GAAFET (Gate-All-Around FET): The gate completely encircles all four sides of the channel.

Key Feature and Advantages

The "all-around" design is critical for improving chip performance and power efficiency in the latest generations of processors.

  • Superior Electrostatic Control: By surrounding the channel entirely, the gate gains far better control over the flow of current. This is the ultimate solution for mitigating the short-channel effect (where leakage current increases as the transistor gets smaller).
  • Reduced Leakage and Power Consumption: The tighter control prevents current from leaking when the transistor is in the OFF state, resulting in a significant reduction in power consumption compared to FinFETs.
  • Increased Drive Current/Performance: The greater interface area between the gate and the channel allows more current to flow when the transistor is ON, which boosts overall device speed and performance.
  • Design Flexibility (Nanosheet Version): Many GAA implementations use nanosheets (horizontally stacked channels) instead of nanowires. This approach, like Samsung's Multi-Bridge-Channel FET (MBCFET™), allows chip designers to adjust the width of the nanosheets. This "tuning" optimizes the balance between performance and power consumption for different parts of the chip, a flexibility not available with FinFET.

Industry Adoption

GAA technology represents the biggest change in logic chip design since FinFET was introduced.

  • Transition Node: The transition from FinFET to GAA began around the 3nm technology node.
  • Key Players: Major foundries like Samsung, TSMC, and Intel are all adopting their own versions of GAA/Nanosheet technology for their most advanced process nodes.