Hot electron induced beta degradation has been observed from fiber optic transistors after multiple parametric testing. Beta degradation originated from increasing base leakage current due to the multiple testing. Base leakage current increases were directly related to the hot electron phenomenon at Si-SiO2 interface layer. The hot electron effect broke down the trivalent silicon and its hydrogen compounds (SisH) at the interface layer, which created mobile interstitial hydrogen atoms (Hi) and trivalent silicon atoms Si* (interface trap charges) at the same time. Typically, the SisH forms during the post metallization anneal. This paper will outline the following topics: 1.) The generation of mobile hydrogen atoms and trap charges at the Si-SiO2 interface due to the hot electron phenomenon and its relationship to transistor beta degradation. 2.) A quantitative analysis of hydrogen atoms measured by Secondary Ion Mass Spectrometry (SIMS), and a direct relationship model between beta degradation and hydrogen profiles at the interface layer. 3.) Experimental result showing transistor beta recovery as well as the repopulation of the hydrogen atoms at the interface layer after low temperature annealing (150 °C to 200 °C bake).

This paper outlines a methodology which accurately identifies fault locations in Mixed Signal Integrated Circuits (ICs). The architecture of Mixed Signal ICs demands more attention during failure analysis because of the complexity of measuring both the analog and digital signals in a compact circuit. In this paper, the GHz range of data signal or radio frequency (RF) signal from an internal IC circuit will be extracted by a high-impedance active single probe in order to find the internal IC circuit failure locations. The advantages of using a single probe is that it can maneuver to extract data almost anywhere in the circuit, providing ranges of bandwidth in GHz with no loading effect on the circuits during measurement. The process of preparing a sample and extracting a signal will be described.