Backside PN junction diode

A semiconductor structure, comprising:

• a backside conductive feature extending lengthwise along a first direction;
• a silicide layer disposed on the backside conductive feature and extending along the first direction;
• an epitaxial layer disposed on the silicide layer and extending along the first direction;
• a semiconductor feature disposed on the epitaxial layer and extending along the first direction;
• a first source/drain feature and a second source/drain feature disposed over the semiconductor feature;
• a plurality of nanostructures extending between the first source/drain feature and the second source/drain feature along the first direction;
• and
• a gate structure wrapping around each of the plurality of nanostructures,
• wherein the first source/drain feature is electrically coupled to the backside conductive feature.

A device, comprising:

• a first PN junction diode comprising:
• a well region doped with a dopant of a first conductivity type,
• a first epitaxial feature disposed over the well region, the first epitaxial feature being doped with a dopant of a second conductivity type different from the first conductivity type,
• a first contact disposed on and in contact with the first epitaxial feature, and
• a backside conductive feature disposed below the well region;
• and
• a second PN junction diode comprising:
• a second epitaxial feature disposed over the well region and spaced apart from the first epitaxial feature, the second epitaxial feature being doped with the dopant of the first conductivity type,
• a plurality of nanostructures extending between the first epitaxial feature and the second epitaxial feature along a first directions, and
• the first epitaxial feature.