Analytical threshold voltage model for ultrathin SOI MOSFET´s

The threshold voltage of fully depleted silicon-on-insulator (SOI) MOSFET with channel lengths down to the deep-submicrometer range has been investigated. By applying Gauss´s law, a quasi-two-dimensional analytical threshold voltage model for ultra-thin SOI fully depleted MOSFET´s including the short-channel effect (SCE) is achieved. Furthermore, we consider further the threshold voltage of FDSOI MOSFET and in particular the value of the surface potential at threshold. It is shown that the surface potential at FDSOI MOSFET threshold may differ significantly from 2 φ i. We extend this model by accounting for surface potential about P+ poly-silicon gate, a closed form expression for the threshold voltage is obtained and compared with experimental data for several SOI FD MOSFET´s