Precise Analytical Model for Short-Channel Quadruple-Gate Gate-All-Around MOSFET

A compact analytical model is presented for crossover point, subthreshold slope, virtual cathode position, and threshold voltage for a short-channel quadruple-gate (QuaG) gate-all-around (GAA) MOSFET. The potential distribution in the channel is obtained by an analytical solution of 3-D Poisson's equation, where the electron quasi-Fermi level is approximated to be zero for low drain-to-source voltages. Using isomorphic polynomial function for potential distribution, we have analyzed, for the first time, the crossover point for the QuaG GAA MOSFET. Further, the modeled subthreshold slope for lightly doped QuaG GAA MOSFET has been improved by introducing z-dependent characteristic length, and the position of minimum center potential in the channel is obtained by virtual cathode position. A model is proposed for threshold voltage, based on shifting of the inversion charge from center line to silicon-insulator interface.