A new mixed-mode base current degradation mechanism is identified in bipolar transistors for the first time, which, at room temperature, induces a large I/sub B/ leakage current only after simultaneous application of both high J/sub C/ and high V/sub CB/. This new mechanism differs fundamentally from well-known I/sub B/ degradation mechanisms such as the reverse EB voltage stress, high forward current stress and damage due to ionizing radiation. Extensive measurements and two-dimensional (2-D) simulations have been used to help understand the device physics associated with this new degradation mechanism.

A new "mixed-mode" reliability degradation mechanism in advanced Si and SiGe bipolar transistors