Overview of Aging Mechanisms in Sige Hbts

Abstract

This paper reviews the recent studies in hot carrier degradation mechanisms of SiGe HBTs under saturation mode and off-state operation. Reliability of these devices gets increased scrutiny as technological scaling drives down device dimensions. Even as the performance of these devices increases, the hot carrier generation and reaction kinetics concepts driving degradation in sensitive regions of the device remain the same. The new mechanisms discussed here can be broadly categorized using the physics of high-voltage or high-current electrical stress conditions that have been well-studied. Measurements and TCAD simulations suggest that voltage-limited mechanisms consistently see worse degradation at lower temperatures while current-limited mechanisms respond to both higher temperature and higher current density. These limitations must be carefully evaluated during the development of new technologies and circuits.