A 3-DIMENSIONAL MOSFET SOLVER IMPLEMENTING THE FIXED-POINT ITERATION TECHNIQUE

Our implementation of a fixed-point iteration technique for the three- dimensional (3D) steady-state simulation of MOSFET devices is presente d. The simulation program is employed to investigate narrow channel ef fects on the device current-voltage characteristics. Particularly, the effects of impact ionization and the effects of variations in channel width and the field oxide bird's beak angle are evaluated. The degree to which various field oxide configurations isolate the device from t he gate contact over the oxide transition region is determined by comp aring the current-voltage characteristics with those of an idealized d evice with perfect isolation. Perfect isolation is simulated by settin g the normal component of the electric field to zero at the semiconduc tor-field oxide interface. Simulation results show that the 3D computa tions are essential to account for rapidly varying charge densities an d generation rates near the channel edge. Moreover, it is observed tha t the isolation effects of field oxides increase for larger bird's bea k angles.