Computer simulation of hot-carrier effects in asymmetric LDD and LDS MOSFET devices

Both symmetric and asymmetric lightly doped drain (LDD) and lightly doped source (LDS) structures for the short n-channel Si MOSFET are studied using a two-dimensional hot-carrier-device simulation program. From the simulation results for the substrate and gate currents, it is found that although the LDD structure reduces hot-carrier effects for V_gd, the LDS structure greatly enhances the hot carrier injection for V_g>or=1.5 V_d. Thus suggests that the latter could be used in the design of a high-performance EPROM (electrically programmable read-only memory).