One or more semiconducting or conducting regions of a device such as a transistor may comprise molecular materials such as nanotubes or similar materials. Regions of a conductive alignment pattern used to align the nanotubes may be proximate to one or more ends of the nanotube. Additionally, a contact region may be proximate to each end of the nanotube to provide electrical contact to the nanotube. Nanotubes or the like may be in communication with device interconnection regions on a device substrate and may further be in communication with a package connection region on a package substrate.
A method and structure for an integrated circuit comprising a first transistor and an embedded carbon nanotube field effect transistor (CNT FET) proximate to the first transistor, wherein the CNT FET is dimensioned smaller than the first transistor. The CNT FET is adapted to sense signals from the first transistor, wherein the signals comprise any of temperature, voltage, current, electric field, and magnetic field signals. Moreover, the CNT FET is adapted to measure stress and strain in the integrated circuit, wherein the stress and strain comprise any of mechanical and thermal stress and strain. Additionally, the CNT FET is adapted to detect defective circuits within the integrated circuit.
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.
Disclosed is a CNT technology that overcomes the intrinsic ambipolar properties of CNTFETs. One embodiment of the invention provides either a stable p-type CNTFET or a stable n-type CNTFET. Another embodiment of the invention provides a complementary CNT device. In order to overcome the ambipolar properties of a CNTFET, source/drain gates are introduced below the CNT opposite the source/drain electrodes. These source/drain gates are used to apply either a positive or negative voltage to the ends of the CNT so as to configure the corresponding FET as either an n-type or p-type CNTFET, respectively. Two adjacent CNTFETs, configured such that one is an n-type CNTFET and the other is a p-type CNTFET, can be incorporated into a complementary CNT device. In order to independently adjust threshold voltage of an individual CNTFET, a back gate can also be introduced below the CNT and, particularly, below the channel region of the CNT opposite the front gate. In this manner parasitic capacitances and resistances are minimized.
