A novel characterization tool for the study of dielectric breakdown of ultra-thin oxide MOS structures

Dielectric breakdown of ultra-thin oxide MOS structures of integrated circuits is preceded by a precursory stage characterized by random on-off fluctuations of the current tunneling through the oxide. In this paper a new version of a low noise measurement system capable of monitoring these phenomena in a band of 1 kHz is presented. The instrument, controlled by a Personal Computer which stores and elaborates the acquired data, is capable of recognizing the current fluctuations announcing the proximity of the breakdown, so allowing the interruption of the test just a few seconds before the destruction of the sample. Some preliminary observations, made possible by the use of this new analysis tool, are presented in the paper.