Effective boundary conditions for carriers in ultrathin SOI channels

We have studied electron backscattering from heavily doped source/drain extensions using both the solution of Boltzmann equation and Monte Carlo simulation, for a simple case of monochromatic incident beam of ballistic electrons. For the case of elastic scattering, numerical results for the total reflection coefficient R may be well described by a simple expression which has a clear physical sense within the Landauer formalism of mesoscopic transport. The reduction of R due to inelastic scattering was also analyzed using Monte Carlo simulation. We believe that our work paves a way toward simple and accurate modeling of nanoscale MOSFETs with thin electrode extensions.