EFFECTS OF ELECTRON-BEAM DAMAGE ON THE ELECTRICAL CHARACTERISTICS OF N-TYPE METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT-TRANSISTORS

The effects of electron beam damage on the degradations of n-type meta l-oxide-semiconductor field-effect-transistors (n-MOSFETs) due to the creation of interface traps were investigated using charge-pumping and subthreshold slope measurement methods. The in situ device characteri stics such as threshold voltage were not changed much by the electron beam damage as compared with those of virgin ones if the devices were annealed properly. The long-term reliability characteristics, however, were significantly degraded even with a small dose of electron beam i rradiation. Moreover, device lifetimes were shown to decrease at a fas t rate as the electron beam irradiation dose was increased even after annealing. It was also observed that the interface trap density depend ency on electron beam irradiation dose investigated by the charge-pump ing method was highly consistent with that by the subthreshold slope m easurement technique.