Ground Plane Impact on Performance of Relaxed Ge FinFETs

The implementation of a barrier potential layer underneath the channel region, well known as Ground Plane (GP) implantation, and its influence on the performance of relaxed germanium pFinFET devices is investigated in this manuscript. This study aims to explain the fin width dependence of the threshold voltage from experimental data and evaluates the ground plane doping concentration and its depth influence on relaxed p-type channel germanium FinFET parameters, as threshold voltage, transconductance and subthreshold swing, through Technology Computer-Aided Design (TCAD) numerical simulations. The threshold voltage variation reaches up to 80 mV from the narrowest device to the widest one, considering the studied range of ground plane doping concentration. Concerning the subthreshold swing parameter, neither the GP doping concentration, nor its depth play a significant role since the electrostatic coupling is predominant.