Epitaxial features confined by dielectric fins and spacers

A semiconductor structure, comprising:

• a substrate;
• first and second semiconductor fins extending upwardly from the substrate, wherein the first semiconductor fin extends to a first height over the substrate;
• an isolation structure over the substrate and on sidewalls of the first and second semiconductor fins;
• first and second epitaxial features over the first and second semiconductor fins respectively;
• a dielectric fin partially embedded in the isolation structure and projecting upwardly above the isolation structure, wherein the dielectric fin is between the first and second semiconductor fins, wherein the dielectric fin and the first and second semiconductor fins are arranged lengthwise along a same direction from a top view, wherein the dielectric fin extends to a second height over the substrate that is greater than the first height;
• and
• first and second spacer features over the isolation structure, wherein the first spacer feature is laterally between the first epitaxial feature and the dielectric fin, and the second spacer feature is laterally between the dielectric fin and the second epitaxial feature, wherein a majority of the first and second epitaxial features are below a top surface of the first and second spacer features.

A semiconductor structure, comprising:

• a substrate;
• a semiconductor fin extending upwardly from the substrate;
• an epitaxial feature over the semiconductor fin;
• an isolation structure over the substrate and on sidewalls of the semiconductor fin;
• first and second dielectric fins partially embedded in the isolation structure and projecting upwardly above the isolation structure, wherein the semiconductor fin is between the first and second dielectric fins;
• a gate stack over and engaging the semiconductor fin and the first and second dielectric fins;
• a spacer layer covering sidewalls of the gate stack and sidewalls of each of the first and second dielectric fins, wherein the spacer layer also covers sidewalls of the epitaxial feature;
• and
• a contact disposed over the first dielectric fin, wherein the first dielectric fin extends into the contact.