Quantum transport in silicon double-gate MOSFET

The full complex band structure model in ultra-scaled (~10 nm) DG MOSFETs is studied. Building on a previous 2D / 1D model, we have included a more realistic band structure to describe the quantum transport. The empirical tight-binding Hamiltonian, rather than that based on effective mass theory, is used directly in the NEGF formalism. The nearest and second nearest neighbor coupling are taken into account to obtain an accurate Si band structure model. Use of the complex band structure causes the carrier to see a more transparent potential barrier than that based on effective mass theory. The ldquooffrdquo state tunneling current is increased. However, our analysis confirms the adequacy of an effective mass treatment for the sub-threshold current, that is, the differences are minimal for Si DG MOSFETs even down to ~10 nm channel length. But the complex band structure effect could be more important if the channel length is further scaled down or for low temperature operation.