Doping dependent stacked channel FinFET for multiple threshold voltage applications

A new approach for the solution of multiple threshold voltage and low power behavior of trigate bulk FinFETs has been demonstrated using variation in doping of stack channel. First, lightly doped Si is stacked over the strained SiGe channel to enhance the driving current. Afterward, variable doping of SiGe region of the channel cause mismatch in threshold voltage. Using TCAD simulation the device performance are also compared with lightly doped and heavily doped uniform SiGe channel FinFETs. It is observed that the OFF current is reduced by ~2.5-3× at higher doping for stack FinFET. However, as compared to highly doped uniform channel the threshold voltage is improved up to 15% for stack FinFET.