Moderated degradation enhancement of lateral pnp transistors due to measurement bias

Enhanced low-dose-rate gain degradation of ADI RF25 lateral pnp transistors is examined as a function of the bias at which the gain is measured. Degra dation enhancement at low dose rates diminishes rapidly with increasing mea surement bias between the emitter and the base. Device simulations reveal t hat interface trap charging, field effects from oxide trapped charge and em itter metallization, base series resistance and high-level carrier injectio n all contribute to this behavior. As a practical consequence, accelerated hardness assurance tests of this device require higher irradiation temperat ures or larger design margins for low power applications.