Semiconductor device

A semiconductor device, comprising:

• a plurality of first semiconductor nanostructures formed over a substrate;
• a first hard mask layer formed over the first semiconductor nanostructures, wherein a bottommost surface of the first hard mask layer is higher than a topmost surface of the first semiconductor nanostructures;
• a plurality of second semiconductor nanostructures formed over the substrate;
• a second hard mask layer formed over the second semiconductor nanostructures;
• a gate dielectric layer surrounding the first semiconductor nanostructures and the second semiconductor nanostructures, wherein the first hard mask layer and the second hard mask layer are surrounded by the gate dielectric layer;
• and
• an isolation structure extending upwardly above the surface, wherein a top surface of the isolation structure is higher than a topmost first semiconductor nanostructure.

A semiconductor device, comprising:

• a STI structure formed over a substrate;
• a plurality of first semiconductor nanostructures formed over a first fin base over the substrate, wherein the first semiconductor nanostructures are directly over the first fin base;
• a plurality of second semiconductor nanostructures formed over the substrate;
• a gate metal fill formed over the first semiconductor nanostructures and the second semiconductor nanostructures;
• and
• an isolation structure between the first semiconductor nanostructures and the second semiconductor nanostructures, wherein a bottom portion of the isolation structure is lower than a top surface of the STI structure.