The electron transport properties of different Silicon on Insulator (SOI) devices have been studied. We have considered
two type of semiconductor structures: i) quantum-well SOI structures and ii) quantum-wire devices. In the first group,
Qwell-based devices, the electron mobility in double-gate SOI devices as the silicon thickness, decreases was compared
with the mobility in Single-Gate SOI structures. Thus, we determined the existence of a range of silicon layer thicknesses
in which electron mobility in DGSOI inversion layers is significantly improved as compared to bulk-silicon or SGSOI
inversion layers, due to the volume inversion effect. With regard to QWire-based devices, we have analyzed the phonon-limited
mobility in silicon quantum wires by means of a one-particle Monte Carlo simulator. It has been observed that
the increasing of the phonon scattering produces a noticeable reduction of the electron mobility observed when the device
dimensions are reduced. Therefore, we have observed that the transition from a 2D to a 1D electron gas produces a
degradation of the electron transport properties.
We study the electron transport in ultrathin silicon inversion layers with thickness in a range from 20nm down to 2nm by Monte Carlo simulation. Quantum effects are taken into account by simultaneously solving the Poisson and Schroedinger equations. Once the electron distribution in the silicon layer is known, the effect of a longitudinal electric field applied parallel to the silicon slab is studied. To do so, the Boltzmann transport equation is solved by the Monte Carlo method, and the electron mobility is evaluated. The influence of different scattering mechanisms has been analyzed. We show that two opposite effects appear on the electron mobility as the silicon thickness is reduced. On one hand the subband modulation effect, which contributes to an increase in the electron mobility. On the other hand, the greater confinement of the carriers as the silicon thickness decreases produces, as a consequence of the uncertainty principle, an increase of the phonon scattering rate, and therefore a decrease on the electron mobility. The superposition of these two opposite effects makes that electron mobility does not have a clear trend as the silicon slab thickness decreases.