Taiwan Semiconductor Manufacturing Company Limited
Antenna-free high-k gate dielectric for a gate-all-around transistor and methods of forming the same

Abstract:

A gate-all-around field effect transistor may be provided by forming a sacrificial gate structure and a dielectric gate spacer around a middle portion of a semiconductor plate stack. A source region and a drain region may be formed on end portions of semiconductor plates within the semiconductor plate stack. The sacrificial gate structure and other sacrificial material portions may be replaced with a combination of a gate dielectric layer and a gate electrode. The gate dielectric layer and the gate electrode may be vertically recessed selective to the dielectric gate spacer. A first anisotropic etch process recesses the gate electrode and the gate dielectric layer at about the same etch rate. A second anisotropic etch process with a higher selectivity may be subsequently used. Protruding remaining portions of the gate dielectric layer are minimized to reduce leakage current between adjacent transistors.