Forming non-line-of-sight source drain extension in an NMOS FINFET using n-doped selective epitaxial growth

A finFET device, comprising:

• a semiconductor substrate having a bulk semiconductor region;
• a semiconductor fin structure that is disposed on the bulk semiconductor region, the semiconductor fin structure comprising:
• a source extension region epitaxially grown on the bulk semiconductor region, the source extension region comprising a first n-type dopant;
• a drain extension region epitaxially grown on the bulk semiconductor region, the drain extension region comprising the first n-type dopant;
• a first carbon-containing layer that is surrounded by the source extension region and not in direct contact with the bulk semiconductor region;
• a second carbon-containing layer that is surrounded by the drain extension region and not in direct contact with the bulk semiconductor region;
• a source region comprising a second n-type dopant, wherein the source region is surrounded by the first carbon-containing layer and not in direct contact with the bulk semiconductor region;
• a drain region comprising the second n-type dopant, wherein the drain region is surrounded by the second carbon-containing layer and not in direct contact with the bulk semiconductor region;
• and
• a channel region between the source extension region and the drain extension region;
• and
• a gate electrode structure that is formed on a portion of the semiconductor fin structure, the gate electrode structure comprising:
• a gate electrode layer;
• a first gate spacer formed on a first sidewall of the gate electrode layer and on the source extension region;
• and
• a second gate spacer formed on a second sidewall of the gate electrode layer and on the drain extension region wherein
• the first n-type dopant is different than the second n-type dopant,
• the first n-type dopant in the source extension region prevents diffusion of the second n-type dopant in the source region to the channel region, and
• the first n-type dopant in the drain extension region prevents diffusion of the second n-type dopant in the drain region to the channel region.