Threshold voltage control using channel digital etch

Abstract

A method is presented for fine-tuning a threshold voltage of a nanosheet structure. The method includes forming a nanosheet stack over a substrate including a plurality of sacrificial layers and a plurality of nanowires, forming a sacrificial gate structure over the nanosheet stack, and partially etching one or more sacrificial layers to form cavities, the partial etching resulting in remaining sections of sacrificial layers. The method includes removing the sacrificial gate structure, removing at least one of the remaining sections of sacrificial layers to expose a surface of each of the plurality of nanowires, forming an oxidation channel on the exposed surface on only either a top side or bottom side of each of the plurality of nanowires, removing the oxidation channels to form a recess on each of the plurality of nanowires, and depositing a high-k metal gate extending into the recess of each of the plurality of nanowires.

Dependencies are inferred from the claim text.