Method of manufacturing a field effect transistor using carbon nanotubes and a field effect transistor

A semiconductor device having a gate-all-around field effect transistor, comprising:

• carbon nanotubes (CNTs) disposed over a substrate and extending along a first direction;
• a gate structure formed around the CNTs in a channel region and extending along a second direction crossing the first direction;
• a source/drain contact formed around the CNTs in a source/drain region;
• and
• a dielectric layer, wherein:
• in a cross section cutting the source/drain contact, the dielectric layer and the CNTs in the source/drain region by a plane parallel with the second direction and a third direction crossing the first and second directions, the source/drain contact is in direct contact with only a part of each of the CNTs and the dielectric layer partially covers each of the CNTs and is disposed between the source/drain contact and each of the CNTs, and
• no CNT contacts another CNT in a vertical direction.

A semiconductor device having a gate-all-around field effect transistor (GAA FET), comprising:

• a first GAA FET;
• and
• a second GAA FET, wherein:
• each of the first GAA FET and the second GAA FET includes:
• carbon nanotubes (CNTs) disposed over a substrate and extending along a first direction;
• a gate structure formed around the CNTs in a channel region and extending along a second direction crossing the first direction;
• a source/drain contact formed around the CNTs in a source/drain region;
• and
• a dielectric layer,
• wherein in a cross section cutting the source/drain contact, the dielectric layer and the CNTs in the source/drain region by a plane parallel with the second direction and a third direction crossing the first and second directions, the source/drain contact is in direct contact with only a part of the CNTs and the dielectric layer partially covers the CNTs and is disposed between the source/drain contact and the CNTs.