Contact structure for semiconductor device

A method of forming a semiconductor device, comprising:

• forming a source/drain region on a substrate;
• forming a source/drain contact structure on the source/drain region;
• forming a concavely-curved surface at the source/drain contact structure;
• and
• forming insulating spacers on sidewalls of the source/drain contact structure.

A method of forming electrical connection between a source/drain region and a metal interconnect in a semiconductor structure, comprising:

• forming a first interlayer dielectric (ILD) layer over the source/drain region;
• forming a second ILD layer over the first ILD layer, wherein the second ILD layer includes a dual-damascene interconnect structure;
• and
• forming a source/drain contact structure within the first and second ILD layers and between the source/drain region and the metal interconnect, wherein forming the source/drain contact structure comprises forming a concavely-curved interface between the source/drain contact structure and the metal interconnect.