A transistor device includes a substrate; a source region and a drain region formed over the substrate; and a source/drain contact formed in contact with at least one of the source region and the drain region, the source/drain contact including a conductive metal and a bilayer disposed between the conductive metal and the at least one of the source and drain region, the bilayer including a metal oxide layer in contact with the conductive metal, and a silicon dioxide layer in contact with the at least one of the source and drain region.

Tunnel field effect devices and methods of fabricating tunnel field effect devices are described. In one embodiment, the semiconductor device includes a first drain region of a first conductivity type disposed in a first region of a substrate, a first source region of a second conductivity type disposed in the substrate, the second conductivity type being opposite the first conductivity type, a first channel region electrically coupled between the first source region and the first drain region, the first source region underlying a least a portion of the first channel region, and a first gate stack overlying the first channel region.

A tunnel field-effect transistor device includes a p-type GaN source layer, an n-type GaN drain layer, and an interlayer interfaced between the source-layer and the drain layer. In one example, the interlayer includes an Indium Nitride (InN) layer. In one example, the interlayer includes a graded Indium gallium nitride layer and an InN layer. In one example, the interlayer may include a graded Indium gallium nitride (In.sub.xGa.sub.1-xN) layer and an Indium gallium nitride (InGaN) layer. In one example, the tunnel field-effect transistor device includes an in-line configuration. In one example, the tunnel field-effect transistor device includes a side-wall configuration.

A tunnel field-effect transistor device includes a p-type GaN source layer, an ntype GaN drain layer, and an interlayer interfaced between the source-layer and the drain layer. These devices employ polarization engineering in GaN/InN heterojunctions to achieve appreciable interband tunneling current densities. In one example, the interlayer includes an Indium Nitride (InN) layer. In one example, the interlayer includes a graded Indium gallium nitride layer and an InN layer. In one example, the interlayer may include a graded Indium gallium nitride (In.sub.xGa.sub.1-xN) layer and an Indium gallium nitride (InGaN) layer. In one example, the tunnel field-effect transistor device includes an in-line configuration. In one example, the tunnel field-effect transistor device includes a side-wall configuration. In one example, the tunnel field-effect transistor device includes a nanowire cylindrical gate-all-around geometry to achieve a high degree of gate electrostatic control.

A semiconductor substrate includes lower source/drain (S/D) regions. A replacement metal gate (RMG) structure is arranged upon the semiconductor substrate between the lower S/D regions. Raised S/D regions are arranged upon the lower S/D regions adjacent to the RMG structure, respectively. The raised S/D regions may be recessed to form contact trenches. First self-aligned contacts are located upon the raised S/D regions within a first active area and second self-aligned contacts are located upon the recessed raised S/D regions in the second active area. The first and second self-aligned contacts allows for independent reduction of source drain contact resistances. The first self-aligned contacts may be MIS contacts or metal silicide contacts and the second self-aligned contacts may be metal-silicide contacts.

An electrical circuit is disclosed that comprises plurality of tunneling field-effect transistors (TFETs) arranged in a diffusion network matrix having a plurality of nodes wherein, for each of the TFETs that is not on an end of the matrix, a drain of the TFET is electrically coupled with the source of at least one of the other TFETs at a node of the matrix and a source of the TFET is electrically coupled with the drain of at least one of the other TFETs at another node of the matrix. The electrical circuit further comprises a plurality of capacitors, wherein a respective one of the plurality of capacitors is electrically coupled with each node that includes the source of at least one TFET and the drain of at least one TFET. The TFETs may be symmetrical graphene-insulator-graphene field-effect transistors (SymFETs), for example.

The invention is a field-effect transistor with a channel consisting of a thin sheet of one or more atomic layers of lateral heterostructures based on hybridized graphene. The role of lateral heterostructures is to modify the energy gap in the channel so as to enable the effective operation of the transistor in all bias regions. This solution solves the problem of the missing bandgap in single-layer and multi-layer graphene, which does not allow the fabrication of transistors that can be efficiently switched off. The possibility of fabricating lateral heterostructures, with patterns of domains with different energy dispersion relations, enables the realization of field-effect transistors with additional functionalities with respect to common transistors.

A method for forming a transistor is provided. The method includes: forming a channel layer over a substrate; forming a barrier layer between the channel layer and the substrate; forming a recess that extends into the barrier layer through the channel layer; and forming a source layer in the recess.

An electrical contact structure (an MIS contact) includes one or more conductors (M-Layer), a semiconductor (S-Layer), and an interfacial dielectric layer (I-Layer) of less than 4 nm thickness disposed between and in contact with both the M-Layer and the S-Layer. The I-Layer is an oxide of a metal or a semiconductor. The conductor of the M-Layer that is adjacent to and in direct contact with the I-Layer is a metal oxide that is electrically conductive, chemically stable and unreactive at its interface with the I-Layer at temperatures up to 450 C. The electrical contact structure has a specific contact resistivity of less than or equal to approximately 10.sup.5-10.sup.7 -cm.sup.2 when the doping in the semiconductor adjacent the MIS contact is greater than approximately 210.sup.19 cm.sup.3 and less than approximately 10.sup.8 -cm.sup.2 when the doping in the semiconductor adjacent the MIS contact is greater than approximately 10.sup.20 cm.sup.3.

A transistor device includes a substrate; a source region and a drain region formed over the substrate; and a source/drain contact formed in contact with at least one of the source region and the drain region, the source/drain contact including a conductive metal and a bilayer disposed between the conductive metal and the at least one of the source and drain region, the bilayer including a metal oxide layer in contact with the conductive metal, and a silicon dioxide layer in contact with the at least one of the source and drain region.