Embodiments of methods in accordance with the present invention provide
three-dimensional carbon nanotube (CNT) integrated circuits comprising
layers of arrays of CNT's separated by dielectric layers with conductive
traces formed within the dielectric layers to electrically interconnect
individual CNT's. The methods to fabricate three-dimensional carbon
nanotube FET integrated circuits include the selective deposition of
carbon nanotubes onto catalysts selectively formed on a conductive layer
at the bottom of openings in a dielectric layer. The openings in the
dielectric layer are formed using suitable techniques, such as, but not
limited to, dielectric etching, and the formation of ring gate
electrodes, including spacers, that provide openings for depositing
self-aligned carbon nanotube semiconductor channels.