Method of forming epitaxial buffer layer for finFET source and drain junction leakage reduction and semiconductor device having reduced junction leakage

A semiconductor device comprising:

• at least one of a source region and a drain region on a source region portion and a drain region portion of a fin structure, wherein at least one of the source region portion and an epitaxial drain region portion include a first concentration doped portion adjacent to the fin structure, and a second concentration doped portion on the first concentration doped portion, wherein the second concentration portion has a greater dopant concentration than the first concentration doped portion;
• and
• an extension dopant region extending into a channel portion of the fin structure having an abrupt dopant concentration gradient of n-type or p-type dopants of 7 nm per decade or greater.

A semiconductor device comprising:

• at least one of a source region and a drain region on a source region portion and a drain region portion of a fin structure, wherein at least one of the source region portion and an epitaxial drain region portion include a first concentration doped portion adjacent to the fin structure, and a second concentration doped portion on the first concentration doped portion, the second concentration portion having a greater dopant concentration than the first concentration doped portion, wherein the first concentration region has an L-shaped geometry with a vertical portion on a sidewall of the source region portion or drain region portion of the fin structure and a horizontal portion at a base of the source region or drain region;
• and
• an extension dopant region extending into a channel portion of the fin structure having an abrupt dopant concentration gradient of n-type or p-type dopants of 7 nm per decade or greater.