A threshold voltage model of short-channel fully-depleted recessed-source/drain (Re-S/D) UTB SOI MOSFETs including substrate induced surface potential effects

In this paper, a threshold voltage model of short-channel recessed-source/drain (Re-S/D) ultra-thin body (UTB) SOI MOSFETs has been presented considering the substrate induced surface potential (SISP) to improve the model accuracy over wide ranges of device parameters and substrate bias. The potential distribution of the front and the back surfaces of the Si-body have been derived using the evanescent mode analysis method in which the channel potential is broken into one-dimensional long-channel potential and two-dimensional short-channel potential. A one-dimensional Poisson’s equation has also been solved in the substrate region to account the effect of substrate induced surface potential (SISP) at substrate/buried-oxide interface. The minimum front- and back-surface potentials of silicon body have been used to obtain front and back channel threshold voltages, respectively. However, the smaller one between front and back channel threshold voltages is considered to be the threshold voltage of the device. The accuracy of the present model has been extended up to 10 nm channel length by incorporating the quantum effects induced correction term. The model results are verified with simulation results obtained using ATLAS™ from Silvaco.