“…Otherwise, the device is denoted as 2-D short-channel device, for which the 2-D Poisson's equation in the x and y directions has to be solved to obtain the surface potential. At threshold voltage or in the sub-threshold regime, the mobile carrier charges in the channel and polysilicon-depletion effect of the gate electrode (if the gate electrode is polysilicon) [17,18] can be neglected. So, the 2-D Poisson's equation for the electric potential φ(x,y) in the gate dielectric, channel, buried insulator and substrate regions can be written as:…”