Patent ID: 11043425

Abstract:
A method is provided for forming a device. The method includes forming a trench that exposes a source/drain (S/D) feature, wherein the S/D feature is separated from a metal gate structure (MG) by a gate spacer. The method further includes removing the gate spacer to form an air gap and forming a first dielectric layer in the trench, wherein the first dielectric layer partially fills the air gap. The method also includes forming a second dielectric layer over the first dielectric layer in the trench and forming a S/D contact over the S/D feature and the second dielectric layer, wherein the second dielectric layer is different from the first dielectric layer. After forming the S/D contact, the first dielectric layer is removed to extend the air gap; and after removing the first dielectric layer, a third dielectric layer is formed to seal the air gap.