Gate isolation features in semiconductor devices and methods of fabricating the same

Abstract

A method includes forming first and second semiconductor fins protruding from a substrate. Each of the first and second semiconductor fins includes a stack of alternating channel layers and non-channel layers. The method also includes forming a dielectric helmet between and protruding from the first and the second semiconductor fins, forming a dummy gate stack over the dielectric helmet, patterning the dummy gate stack to expose a portion of the dielectric helmet, removing the exposed portion of the dielectric helmet, and forming a metal gate structure, such that a remaining portion of the dielectric helmet separates the metal gate structure between the first and the second semiconductor fins. The method also includes forming a contact feature over a portion of the metal gate structure. A sidewall of the contact feature is between one of the semiconductor fins and the remaining portion of the dielectric helmet.