Transistor structure with low resistance contact

A semiconductor structure, comprising:

• a first mesa and a second mesa extending lengthwise along a first direction, the first mesa comprising a first channel region and a first source/drain region, the second mesa comprising a second channel region and a second source/drain region;
• a first stack of nanostructures disposed over the first channel region;
• a second stack of nanostructures disposed over the second channel region;
• a first source/drain feature in contact with the first stack of nanostructures and disposed over the first source/drain region;
• a second source/drain feature in contact with the second stack of nanostructures and disposed over the second source/drain region;
• a dielectric structure comprising a first portion between the first channel region and the second channel region and a second portion between the first source/drain feature and the second source/drain feature along a second direction perpendicular to the first direction;
• and
• a source/drain contact disposed over the first source/drain feature, the second source/drain feature, and the second portion of the dielectric structure,
• wherein a portion of the source/drain contact extends between the first source/drain feature and the second source/drain feature along the second direction,
• wherein the source/drain contact interfaces the first source/drain feature and the second source/drain feature by way of a silicide layer,
• wherein the source/drain contact interfaces a top surface of the dielectric structure by way of a conductive layer,
• wherein a composition of the silicide layer is different from a composition of the conductive layer.

A semiconductor structure, comprising:

• a first base fin and a second base fin;
• an isolation feature comprising a center portion disposed between the first base fin and the second base fin along a direction, a first portion disposed along a sidewall of the first base fin away from the second base fin, and a second portion disposed along a sidewall of the second base fin away from the first base fin;
• a first source/drain feature disposed over the first base fin;
• a second source/drain feature disposed over the second base fin;
• a dielectric structure disposed over the center portion of the isolation feature and disposed between the first source/drain feature and the second source/drain feature along the direction;
• a first sidewall spacer disposed on the first portion of the isolation feature to interface the first source/drain feature;
• a second sidewall spacer disposed on the second portion of the isolation feature to interface the second source/drain feature;
• and
• a source/drain contact disposed over the first source/drain feature, the second source/drain feature and the dielectric structure,
• wherein a bottom surface of the source/drain contact interfaces top surfaces of the first source/drain feature and the second source/drain feature at a first level and interfaces a top surface of the dielectric structure at a second level lower than the first level.