Building on Atoms: The Leap to Gate-All-Around (GAA) Transistors and the Angstrom Scale

For the past decade, the engine of Moore’s Law has been the FinFET transistor. By raising the silicon channel into a vertical “fin,” the gate could control it from three sides, a revolutionary improvement over older, flat transistors. But at the bleeding edge of the 2-nanometer node—a scale where we are literally counting atoms—the fin is no longer enough. Current leaks between transistors, wasting power and limiting performance. To continue scaling, the industry had to reinvent the transistor itself. The answer is Gate-All-Around.

The Gate-All-Around Field-Effect Transistor, or GAAFET, is the heir apparent to the FinFET throne and the foundational technology of the new “Angstrom Era” of semiconductors. The concept is both elegant and powerful: instead of wrapping the channel on three sides, the gate now completely envelops it from all four sides.

This 360-degree control is a game-changer. It dramatically chokes off the quantum-level current leaks that plague advanced FinFETs, leading to stunning improvements in efficiency. Compared to its predecessor at the same node, GAA architecture can deliver:

• Up to a 50% reduction in power consumption.
• A 25-30% boost in performance (speed).
• A significant reduction in silicon area.

The first implementation of this technology, which leaders like Samsung and Intel are rolling out for their most advanced processes, uses horizontal, sheet-like channels of silicon called nanosheets. A single transistor can contain a stack of these sheets, all completely surrounded by the gate. This structure gives designers a powerful new tool: the ability to change the width of the nanosheets to tune a transistor’s performance, prioritizing either higher drive current for speed or lower power consumption—a flexibility FinFETs never had.

While GAAFETs and nanosheets are enabling the current leap forward in the macro-level world of 3D chip stacking, the roadmap doesn’t stop here. The next logical step is to stack the transistors themselves. Future architectures like CFETs (Complementary FETs) will stack N-type and P-type transistors directly on top of one another, pushing density to its theoretical limits. Beyond that, the industry is already experimenting with replacing silicon altogether with exotic 2D materials like tungsten disulfide, which are only a single atom thick.

For now, the story of the GAA transistor is a masterclass in atomic-scale engineering. It’s a leap that ensures the custom AI accelerators and complex chiplet systems being designed today have a foundation to build upon. Yet, even as we perfect control over the charge of an electron, a new frontier awaits—one that seeks to harness its quantum spin, potentially unlocking an even greater paradigm shift in energy-efficient computing.