Temperature, Stress and Hot Phonons in GaN Electronics and its Interfaces

Temperature, Stress and Hot Phonons in GaN Electronics and its Interfaces

Abstract -

GaN power electronics has great potential for future radar and communication applications. Huge advances in their performance have made this new material system superior to GaAs and Si in particular in terms of power performance. However, there are still large reliability challenges which need to be addressed, often related to high device temperature and large stresses in the devices. Those are very challenging to assess as these are present only in sub-micron device regions typically located near the gate of an HEMT. I report on our work of the development of Raman thermography, to assess temperature, stress as well as hot phonon effects in AlGaN/GaN but also GaAs pHEMTs to address reliability challenges in power electronics. The techniques developed enable temperature and stress measurement in devices with submicron spatial and nanosecond time resolution. Effects of thermal cross-talk, but also heat transfer across interfaces in the devices will be discussed, together with hot-phonon effects.