Optimization of Leakage Current Suppression for Super Steep Retrograde Well (SSRW) 5nm-node FinFET Technology

Abstract

Optimization of well doping under the fin of FinFET structure is critical for suppressing the leakage current in sub-5nm-node technology. Through the doping of the super steep retrograde well (SSRW) process, not only the leakage current can be reduced, but also the electrical variation caused by the process variation can be effectively suppressed. In this paper, the implant energy and well doping concentration for the process optimization of the retrograde well were investigated by simulation tools. It was found that the SSRW implant energy for n-type and p-type FinFET can have the optimized leakage current at a depth of about 40 nm. Increasing the SSRW doping can effectively reduce the leakage current. The high SSRW doping concentration leads to band bending thus confine the electron/hole in the fin channel. The optimal SSRW condition of p-type FinFET is 50 keV implant energy with doping 1×1019 cm−3 and n-type FinFET is 9 keV implant energy with doping 1×1019 cm−3.