Monte Carlo simulations of p- and n-channel dual-gate Si MOSFET's at the limits of scaling

Previous work which used the Monte Carlo model DAMOCLES to explore the limits of scaling for n-channel Si MOSFETs is extended to include p-channel Si MOSFETs and quantization effects in the n-channel FETs. The previously published n-channel results (see D.J. Frank et al., 1992) have been resimulated taking into account the quantization of the electrons in the very narrow channel using the quantum capabilities in DAMOCLES. Because of the double-gated structure of these devices, the quantized levels extend to well above the 1 eV achieved by hot electrons, a regime in which the full band structure ought to be used. Since quantization of the full band structure is not practical, the calculations have been carried out in both parabolic and first-order nonparabolic approximations, to evaluate the differences. The two methods differ by up to 30%, with the parabolic case showing higher currents and carrier velocities. The nonparabolic case, which is thought to be more reliable, shows a approximately 15% increase in current compared to the nonquantum simulations, and has a lower source-to-drain resistance of 0.19 Omega mm, indicative of a higher channel mobility.