Nanowire transistor structure and method of shaping

A method of fabricating a semiconductor structure, the method comprising:

• forming a body comprising a semiconductor material;
• forming a subfin beneath the body;
• forming a gate structure wrapped around the body, and the gate structure on a top and along sidewalls of the subfin, the gate structure including a gate electrode and a gate dielectric between the body and the gate electrode, and the gate structure including a gate spacer;
• and
• forming a source region and a drain region, the body being between the source and drain regions;
• wherein the body has a first cross-sectional shape under the gate dielectric and a second cross-sectional shape under the gate spacer, wherein the first cross-sectional shape is more rounded than the second cross-sectional shape, and wherein the gate spacer extends vertically beneath the second cross-sectional shape.

A method of fabricating a nanowire transistor structure, the method comprising:

• forming a first region of semiconductor material;
• forming a second region of semiconductor material;
• forming one or more nanowires having a body between a first end portion in contact with the first region and a second end portion in contact with the second region;
• forming a subfin beneath the body of the one or more nanowires;
• and
• forming a gate structure around the body of the one or more nanowires, and the gate structure on a top and along sidewalls of the subfin, the gate structure comprising a gate electrode and a gate dielectric between the gate electrode and the body, and the gate structure including a gate spacer;
• wherein the body of the one or more nanowires has a first cross-sectional shape and the first end portion has a second cross-sectional shape, wherein the first cross-sectional shape is a is more rounded than the second cross-sectional shape, and the first cross-sectional shape has a smaller circumference compared to the second cross-sectional shape, and wherein the gate spacer extends vertically beneath the second cross-sectional shape.