Comparison of deep-submicrometer conventional and retrograde n-MOSFETs

An extensive comparison of the deep-submicrometer conventional and retrograde n-MOSFETs designed for either a low-power or a high-performance technology is made. We compare simulated curves of off-current versus channel length (I_OFF-L) and on-current vs. channel length (I_ON-L). We include parametric dependence upon the channel length L, and aspects of the doping profile, namely surface doping N_S, bulk doping N_B, and depth of the lightly doped surface layer d. At a given L, the comparison of structures with the same I_ON shows that all retrograde profiles exhibit much worse I_OFF. On the other hand, comparison of structures with the same I_OFF shows that all retrograde profiles have lower I_ON. Moreover, judging the short-channel advantages of a proposed device structure based upon the V _T-L roll-off curve without examination of the related I_OFF-L and I_ON-L curves could lead to a mistaken technology assessment