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/sub OFF/-L) and on-current vs. channel length (I/sub ON/-L). We include parametric dependence upon the channel length L, and aspects of the doping profile, namely surface doping N/sub S/, bulk doping N/sub B/, and depth of the lightly doped surface layer d. At a given L, the comparison of structures with the same I/sub ON/ shows that all retrograde profiles exhibit much worse I/sub OFF/. On the other hand, comparison of structures with the same I/sub OFF/ shows that all retrograde profiles have lower I/sub ON/. Moreover, judging the short-channel advantages of a proposed device structure based upon the V/sub T/-L roll-off curve without examination of the related I/sub OFF/-L and I/sub ON/-L curves could lead to a mistaken technology assessment.