nanoribbons on a silicon substrate
Physical singularities of Graphene on the basis of the analysis crystalline and electronic structure, as material for high-efficiency Interconnects chips are considered.
The crystal structure of Graphene represents the two-dimensional form of carbon with a hexagonal crystalline grid. The one-layer crystal consists of two sub lattices, each of which is formed by three of four external electrons atom by means of strong covalent bindings. Untied electrons are in the vertical orbits stretched over and under a plane of a crystalline grid. These electrons can move freely lengthways of Graphene, providing it high electric conductivity. The specific resistance in usual conditions ~ 1 μΩсm at indoor temperature.
Properties of carriers transport in Graphene are defined by the linear law of a dispersion – (p) = c*p with effective speed c* 106 m/s (Fermi speeds). From this it follows that electrons in Graphene submit to two-dimensional analog of Dirac equations. It leads to a row of singularities: charge carriers in Graphene behave as a zero mass quasi-particles. The zero mass of charge carriers in Graphene causes their limiting mobility μ (to μ ~ 200 m2/Vc). Specific electrical resistance of Graphene explorers at indoor temperature can decrease to value ~ 0.1 μΩсm.
Experiments have shown that at free Graphene heat conduction coefficient k 5000 Vtm–1K–1 or in 2.5 times more than at diamond. Heat conduction of Graphene ribbons put on a silicon substrate has appeared almost 10 times less, than at free Graphene, but much more, than at copper. The reduction reason k of Graphene is, as well as in case of mobility decrease, interaction and leak of phonons through contact area Graphene with a substrate.
The spectrum energy of carriers in Graphene has no forbidden band for usual conditions. Therefore fields Graphene transistor can't be made simply. From here there is a sentence to use electronic and thermal properties of Graphene in communication lines nano-transistors VLSI. However, lamination and defects of real samples explorers can prevent it.
Unlike one-layer of Graphene, carriers of charge in a double-layer material at application of exterior electric field have mass. The given effect testifies to possibility of "discovery" a forbidden band and control in its width (in limits from 0 to 250 мэВ).
The method formation of energy states in Graphene for the account (by) creation of special crystalline structures, so-called Graphene Nanoribbons is known. Edges of the tape received by cutting Graphene along grains of a crystallographic axis, have zig-zag structure. These tapes are characterized by properties of metal. Tapes with edges in an orthogonal direction (with arm-chair structure) have a forbidden band and semi-conductor properties.
Technological perspectives by possibility obtaining of Graphene tapes with high-quality metal properties are defined. For nanotransistors circuits with technological norms of 22 nm and more low, Graphene tapes will allow to refuse application copper as explorers of interconnects. However a defining material by manufacture nanotransistors VLSI the Graphene becomes only when it will be possible to produce in demanded scales with necessary properties, the given sizes and the necessary topology. The way to this purpose is added and defined, apparently, by technological perspectives of atomic de-signing.