Effects of S/D doping concentrations on strained SiGe vertical I-MOS characteristics

This paper reports the effects of source and drain doping concentration on the device characteristics of strained SiGe vertical Impact Ionization MOSFET (I-MOS). Silvaco 2-D Atlas simulations were done to examine the device characteristics. It was found that the source-drain doping concentrations had a significant impact on the threshold voltage of the device. With increasing doping concentrations, the threshold voltage values decreased. This can be explained by the higher electric field and the impact generation rates, with increasing doping concentrations. A threshold voltage of 0.9V was obtained for a drain bias of 1.75V, with S/D doping concentration of 10. The effects of S/D doping on subthreshold slopes was also examined with the help of TCAD device simulations.