Process modeling and design procedure for IGFET thresholds

An empirically based process modeling system is discussed for determining ion-implant conditions used to achieve specific IGFET thresholds. Experimental techniques are applied to insure consistency between physical process phenomenon and the numerical algorithms employed. Device threshold design results are presented for active and parasitic IGFET's in a dual polysilicon-gate technology. The utility of this design procedure in multistep processes for determining the effects of various parameters such as screen thickness, final peak concentration, dose, and energy are considered.