Thermal response of active Si in press-fit rectifier diodes by confocal Raman microscopy: Influence of diode design and technology

Overheating resulting from the circulation of high electric currents (in the order of tens of amperes) that some electronic devices undergo when they are in operation, can induce structural modifications such as mechanical stresses that could reduce their lifetime. In order to optimize their performance, understanding the phenomenology that takes place in devices at high-temperature regimen induced under operating conditions is fundamental. In this work, the thermal behavior of the Si-based semiconductor part of several press-fit rectifier diodes with different design and technology (Schottky, Metal Oxide Semiconductor and PN junction) has been studied by Confocal Raman Microscopy. The experiments have been performed on two specific functional parts of the active Si chip (i.e., near and far from the Si/electrode interface), discerning non-thermal effects such as stress and doping from the purely thermal ones with a specific analysis procedure of the Si T2g Raman active mode. This methodology enables an advance, non-destructive and located characterization of the thermal response of the diodes, which will help to optimize the performance of electronic devices and extend their useful life and reliability by avoiding or, at least, minimizing the damage caused by the temperature excess.