Characterization of the self-heating of AlGaN/GaN HEMTs during an electrical stress by using Raman spectroscopy

We report on the non-invasive measurements of the temperature in active AlGaN/GaN HEMTs grown on sapphire substrate during an electrical stress. The original study permits to highlight the drop of the self-heating in operando during the electrical stress by using Raman spectroscopy. Moreover, a correlation between the decrease of the self-heating and the fall of the drain current during the stress has been demonstrated. This study also highlights that the self-heating of the components and the influence of the ageing test on the self-heating are clearly linked to the position where temperature measurements are carried out.