Optimization of V-th roll-off in MOSFET's with advanced channel architecture - Retrograde doping and pockets

Device optimization in the case of retrograde channel profiles (RCP) and po ckets is a very complex task, which also implies some particularities in th e V-th-L behavior, unusual when using uniform doping. The more difficult an d inefficient may be in this case an optimization based on random cut-and-t ry experiments or that based on comprehension-lacking simulation. The analy sis presented in this paper is based on a simple but exhaustive analytical model, Thanks to that we were able to thoroughly explain the physics behind the retrograde profiles and pockets, We have found some very interesting f eatures as for example the existence of the optimal doping and peak positio n of RCP, minimizing the roll-off, In the case of pockets we have discovere d the existence of an ideal, asymptotic V-th-L curve (dependent only on the amount of roll-up one wishes to allow) and have shown how to chose the poc ket implantation conditions in order to follow the ideal curve to the short est channel lengths. Finally, the model and the acquired know-how are demon strated experimentally to give excellent improvements when applied to optim ization of an 0.15 mu m technology.