Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a fin structure disposed over a substrate;
• a source/drain structure disposed over and protruding from the fin structure;
• an interlayer dielectric layer disposed over the fin structure;
• an epitaxial layer disposed over sidewalls of the interlayer dielectric layer and an upper surface of an isolation insulating layer, wherein the upper surface of the isolation insulating layer is opposed to a surface facing the substrate;
• a cap layer disposed over the epitaxial layer and the source/drain structure;
• a high-k dielectric layer disposed over the cap layer;
• and
• a metal layer disposed over the high-k dielectric layer.

A semiconductor device comprising:

• a plurality of fin structures disposed over a substrate, each of the fin structures extends in a first direction;
• an isolation insulating layer disposed between adjacent fin structures, wherein the isolation insulating layer has a first surface and an opposing second surface, and the first surface faces the substrate;
• a plurality of gate structures disposed over each of the plurality of fin structures, each of the gate structures extending in a second direction perpendicular to the first direction;
• dummy gate structures disposed over the isolation insulating layer between adjacent fin structures;
• a plurality of source/drain structures disposed over and protruding from parts of the fin structures not covered by the gate structures;
• an interlayer dielectric layer formed over each of the fin structures outside the plurality of fin structures;
• an epitaxial layer disposed over the interlayer dielectric layer and the second surface of the isolation insulating layer;
• a cap layer disposed over the epitaxial layer and each of the source/drain structures;
• a high-k dielectric layer disposed over the cap layer;
• and
• a metal layer disposed over the high-k dielectric layer.