US Patent 11417750 Gate air spacer for fin-like field effect transistor

Fin-like field effect transistors (FinFETs) and methods of fabrication thereof are disclosed herein. The FinFETs disclosed herein have gate air spacers integrated into their gate structures. An exemplary transistor includes a fin and a gate structure disposed over the fin between a first epitaxial source/drain feature and a second epitaxial source/drain feature. The gate structure includes a gate electrode, a gate dielectric, and gate air spacers disposed between the gate dielectric and sidewalls of the gate electrode.