Oxide Charging Effects by PH3/He Ion Shower Doping

Abstract

ABSTRACTWe report the oxide charging effects on metal oxide semiconductor (MOS) structure caused by PH3/He ion shower doping. The parallel negative shift of flat-band voltage occurred for the ion-doped PETEOS samples even after thermal annealing. When the ion dose was higher, this shift was larger. These results show that a considerable amount of positive charges were induced inside the oxide films after PH3/He ion shower doping process. For the same ion dose, the flat-band voltage shift is larger when the thickness of PETEOS is thicker. When the ion dose was 1.5×1017cm−2 and the thickness of PETEOS was 80nm, the shift of flat-band voltage was larger than −7V. We can conclude that PH3/He ion shower doping process induces the positive charges, which result in the flat band voltage shift of MOS capacitors, in the bulk oxide films when oxide films are exposed to ion shower doping.