Suppression of boron penetration through thin gate oxides by nitrogen implantation into the gate electrode in PMOS devices

PMOS devices with and without nitrogen implant into the gate electrode before doping with boron and with nitridation of the gate oxide were manufactured. The influence of nitrogen on the penetration of boron ions into the substrate through ultra-thin gate oxides was investigated by electrical and SIMS measurements. Boron diffusion can be effectively prevented by high nitrogen concentrations located immediately above the gate oxide and within the polysilicon gate electrode.