Assessment of thermo-mechanical phenomena in Si-based diodes via operando confocal Raman microscopy

Abstract

The deconvolution of the thermal and mechanical stress and other induced effects caused by the electrical current flowing through a semiconductor-based device is often quite challenging. In this work, a novel specific analysis procedure is successfully tested, based on the study of mapped regions from in situ characterization by confocal Raman microscopy. The width of Si T2g Raman mode and its position are used to determine the individual spatial distribution of all phenomena occurring in the Si chip at different current intensities. The method is applied to Si-based press-fit rectifier diodes in forward-bias conditions but can be extended to other devices. The analysis reveals the presence of several regions in the Si chip as a function of their doping level and stress magnitude. Results indicate that the Si component is subjected to a predominant thermal contribution along with other two contributions related to residual and electrically induced effects, whose values differ for each region.