Simulation of DGSOI MOSFETs with a Schrodinger-Poisson based mobility model

Ultra-thin DGSOI transistors are considered as one of the most promising devices for future VLSI. Besides expected improvements in the sub-threshold behavior, a theoretical enhancement of the channel mobility was found by some authors. Here, we apply a quantum-mechanical mobility model, based on an integrated Schrodinger/Poisson solver, to double-gate SOI MOSFETs with a range of silicon slab thickness t_Si and buried-oxide thickness t_box. The main finding is that the theoretical enhancement of effective mobility and on-current at t_Si ≈10 nm is bound to comparable thicknesses of buried and front oxides. If t_box ≈100×t_ox, as e.g. in the case of SIMOX wafers, the volume-inversion related increase of the mobility completely vanishes.