Field dependence of interface-trap buildup in polysilicon and metal gate MOS devices

The electric field dependence of radiation-induced interface- and oxide-trap charge (ΔVot and ΔVit) generation for polysilicon- and metal-gate MOS transistors is investigated at electric fields (Eox) from - 4.2 MV/cm to + 4.7 MV/cm. If electron-hole recombination effects are taken into account, the absolute value of ΔVot and the saturated value of ΔVit for both polysilicon- and metal-gate transistors are shown to follow an approximate E-1/2 field dependence for Eox ≥ 0.4 MV/cm. An E-1/2 dependence for the saturated value of ΔVit was al;so observed for negative-bias irradiation followed by a constant positive-bias anneal