Fin field-effect transistor and method of forming the same

A semiconductor device, comprising:

• a substrate;
• a first fin structure over the substrate and extending along a first lateral direction;
• a second fin structure over the substrate and extending along the first lateral direction;
• a first gate structure extending along a second lateral direction perpendicular to the first lateral direction and straddling the first fin structure;
• a second gate structure extending along the second lateral direction and straddling the second fin structure;
• an isolation structure over the substrate;
• and
• a dielectric cut structure separating the first and second gate structures from each other along the second lateral direction;
• wherein the dielectric cut structure has a diamond-like profile extending into the substrate, and wherein the diamond-like profile includes a first portion and a second portion laterally aligned with the isolation structure and an upper portion of the substrate, respectively.

A semiconductor device, comprising:

• a substrate;
• a first fin structure over the substrate and extending along a first lateral direction;
• a second fin structure over the substrate and extending along the first lateral direction;
• a first gate structure extending along a second lateral direction perpendicular to the first lateral direction and straddling the first fin structure;
• a second gate structure extending along the second lateral direction and straddling the second fin structure;
• an isolation structure over the substrate;
• and
• a dielectric cut structure, together with a first dummy fin structure and a second fin structure each extending along the first lateral direction, that are configured to separate the first and second gate structures from each other along the second lateral direction;
• wherein the dielectric cut structure has a diamond-like profile extending into the substrate, and wherein the diamond-like profile includes a first portion and a second portion laterally aligned with the isolation structure and an upper portion of the substrate, respectively.