Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a fin structure disposed over a substrate, wherein the fin structure extends in a first direction and includes an upper layer, part of the upper layer is exposed from an isolation insulating layer, the isolation insulating layer has a first surface and an opposing second surface, and the first surface faces the substrate;
• a gate structure disposed over part of the fin structure, the gate structure extending in a second direction perpendicular to the first direction;
• a source/drain structure which includes a first portion part of the fin structure not covered by the gate structure;
• an interlayer dielectric layer formed over a second portion of the fin structure;
• and
• a cap layer disposed over the source/drain structure, the second surface of the isolation insulating layer and sidewalls of the interlayer 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 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;
• and
• a cap layer disposed over the epitaxial layer and each of the source/drain structures.