Investigation of the Effects and the Random-Dopant-Induced Variations of Source/Drain Extension of 7-nm Strained SiGe n-Type FinFETs

In this paper, we simulated the effects of the source/drain extensions (SDEs) of the 7-nm strained SiGe n-type FinFETs and the random dopant fluctuations (RDFs) therein by TCAD tools. First, we simulated different SDE lengths and doping concentrations to examine their effects on the device characteristics. Second, we simulated the RDF in SDE to examine the device variability. Simulation results show that increasing the SDE length and decreasing the SDE doping concentration are beneficial for the device characteristics. For the device variability, increasing the SDE length and decreasing the SDE doping concentration reduce the threshold voltage variation (sigma V-T), on-current variation (sigma I-ON), and off-current variation (sigma I-OFF). Therefore, the SDE optimization is critical for both the device performance and the device variability of the 7-nm FinFETs.