A Physics-Based Circuit Aging Model for Mixed-Mode Degradation in SiGe HBTs

Abstract

A physics-based silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) aging model for mixed-mode stress based on the lucky-electron model and reaction-diffusion theory is developed for integration with compact models. An effective aging parameter extraction method is described, and the aging model parameters are fit for a modern SiGe HBT platform. The aging model is implemented as a wrapper in the Cadence Spectre circuit simulator. Device-level aging simulations are shown to be well-matched to measured degradation data. The aging model is further used to explore the effects of aging on a simple current mirror circuit, showing a decrease in mirror ratio with degradation.