Semiconductor device having cut gate dielectric

A device, comprising:

• a substrate;
• a first gate extending along a first direction over the substrate;
• a first gate spacer surrounding the first gate;
• channel structures extending along a second direction different from the first direction;
• a first isolation structure extending across the first gate along the second direction, wherein the first isolation structure separates the first gate into two first gate portions;
• a source/drain feature interfacing the channel structures;
• and
• a second isolation structure, in a plan view, disposed between the first isolation structure and the source/drain feature, wherein the first gate spacer is separated by the first isolation structure into two first gate spacer portions, wherein at least one of the first gate spacer portions is in contact with the first isolation structure and the second isolation structure.

A device, comprising:

• first channel structures over a substrate;
• second channel structures over the substrate;
• shallow trench isolation (STI) regions between the first channel structures and between the second channel structures;
• a first source/drain feature wrapping the first channel structures;
• a second source/drain feature wrapping the second channel structures;
• a dielectric feature laterally between the first source/drain feature and the second source/drain feature, wherein the dielectric feature has opposite sidewalls interfacing with the first source/drain feature and the second source/drain feature, respectively;
• a gate structure across the first channel structures and the second channel structures, wherein the dielectric feature separates the gate structure, and wherein:
• the dielectric feature comprises a first dielectric layer and a second dielectric layer over the first dielectric layer, the dielectric feature interfaces with the first source/drain feature and the second source/drain feature by the first dielectric layer, the dielectric feature interfaces with the gate structure by the second dielectric layer;
• and
• an interlayer dielectric (ILD) layer over the first source/drain feature and the second source/drain feature.