Semiconductor device source/drain region with arsenic-containing barrier region

A structure comprising:

• an active region of a transistor, the active region comprising a source/drain region, the source/drain region comprising:
• a barrier region along a bottom surface and side surface of the source/drain region, the barrier region comprising arsenic having a first dopant concentration;
• and
• an epitaxial material disposed on the barrier region, the epitaxial material comprising phosphorous having a second dopant concentration;
• and
• a gate structure over the active region proximate the source/drain region.

A method of manufacturing a semiconductor device, the method comprising:

• etching a recess in a fin proximate a gate structure, the gate structure being on the fin on a substrate;
• forming a barrier region along a bottom surface and side surface of the recess, the barrier region comprising arsenic;
• and
• epitaxially growing an epitaxial material on the barrier region, the epitaxial material comprising phosphorous.