No abstract

We investigate transport in nanotransistors in the Landauer–Büttiker formalism. A systematic linearization of the general expression for the current response yields the quantum version of the small signal equivalent circuit. This equivalent circuit can be compared with classical schemes so that explicit quantum mechanical expressions for the circuit elements can be extracted. Reducing our analysis to an effective Y-parameter description of the equivalent circuit we find the multi-terminal Büttiker formula except for one extra term. We show that this extra term is essential for the operation of transistors. An application of our theory to a simple transistor model yields a description of mismatch oscillations in the source-drain current experimentally observed in nano-transistors.

We present the nonlinear I-V characteristics of a nanoscale metal-oxide-semiconductor field-effect transistor in the Landauer-Büttiker formalism. In our three-dimensional ballistic model the gate, source, and drain contacts are treated on an equal footing. As in the drift-diffusion regime for ballistic transport a saturation of the drain current results. We demonstrate the quantum mechanism for the ballistic drain current saturation. As a specific signature of ballistic transport we find a specific threshold characteristic with a close-to-linear dependence of the drain current on the drain voltage. This threshold characteristic separates the ON-state regime from a quasi-OFF-state regime in which the device works as a tunneling transistor. Long- and short-channel effects are analyzed in both regimes and compared qualitatively with existing experimental data by Intel [B. Doyle et al., Intel Technol. J. 6, 42 (2002)].