Long-term reliability of silicon bipolar transistors subjected to low constraints

We present in this study the effect of electrical ageing on silicon (Si) NPN bipolar transistors. This study is based on a sample of half-hundred components, which have been fabricated in the early 1980s, which represents an exceptional experience feedback. By means of static and low frequency noise measurements, which are used as diagnostic tools for reliability assessment, we have noticed a good accordance with a physical model based on an oxide charge modulation. We have also used emission microscopy and electron beam-induced current analysis in order to visualize and to localize the defects in the structure. These have been located in the spacer oxide at the periphery of the base-emitter junction.