Evidence of channel profile modification due to implantation damage studied by a new method, and its implication to reverse short channel effects of nMOSFETs

摘要

The reverse short channel effect (RSCE), which is observed as an increase of threshold voltage (Vth) with shorter gate length, is important not only for submicron MOSFET process design but also for understanding basic phenomena which occur in the submicron region. We propose a new method to study RSCE effects and lateral enhanced diffusion by implantation damage. We show clear evidence of channel profile modification of deep-submicron nMOSFETs, by comparing nMOSFETs with the same Lg. Using the extracted diffusivity enhancement by the new method, simulations explain the conventional RSCE well, which indicates that a predominant effect for RSCE is enhanced diffusion due to implantation damage. Also significant is that lateral diffusion modeling could be greatly enhanced by using the new method.