Channel doping-dependent analytical model for symmetric double gate metal-oxide-semiconductor field-effect transistor. I. Extraction of subthreshold characteristics

An analytical 2D model of subthreshold current (I_DSsub), subthreshold swing (S_sub), and threshold voltage (V_TH) roll-off with a variation of channel doping concentration (N_A) for symmetric double gate (DG) metal-oxide-semiconductor field-effect transistor (MOSFET) is presented. First of all, the channel potential is obtained by solving the 2D Poisson's equation with the help of the evanescent method. Based on the obtained channel potential, I_DSsub, S_sub, and V_TH roll-off expressions are derived in the analytical model. It is shown that the subthreshold characteristics predicted by the analytical model are in good agreement with commercially available 2D numerical simulation results for different channel length (L), channel film thickness (t _si), gate oxide (t_ox), and N_A.