ISOLATION STRUCTURES OF FINFET SEMICONDUCTOR DEVICES

A method of fabricating a semiconductor device is provided, which includes providing sacrificial gate structures over a plurality of fins, wherein the sacrificial gate structures include a first sacrificial gate structure and a second sacrificial gate structure. A fin cut process is performed to form a fin cut opening in the first sacrificial gate structure. A gate cut process is performed to form a gate cut opening in the second sacrificial gate structure. A first dielectric layer is deposited in the fin cut opening and the gate cut opening, and the first dielectric layer is recessed in the openings. A second dielectric layer is deposited over the first dielectric layer in the fin cut opening and the gate cut opening to concurrently form a diffusion break structure and a gate cut structure respectively.