Visualization of ionizing-radiation and hot-carrier stress response of polysilicon emitter BJTs

Process and device simulation software tools are used to produce an animated visualization of the mechanisms involved in the ionizing-radiation and hot-carrier stress responses of BJTs. A physically-based model is presented, which compares ionizing-radiation response with hot-carrier response in poly-silicon-emitter BJTs. During ionizing radiation, positive charge accumulates along the oxide-silicon interface. The accumulated charge causes excess base current to flow, characterized by an ideality factor between one and two for low total doses of ionizing radiation, and an ideality factor of two for high total doses of ionizing radiation. During hot-carrier stress, the oxide damage is localized near the emitter-base junction, and the excess base current has an ideality factor of two.<>