A complete methodology for assessing GaN behaviour for military applications

For military applications, due to a very long life cycle, great power requirements and numerous (>1000) HPA (High Power Amplifier) per system, GaN power devices are considered as critical components. So, an independent assessment made in a government laboratory was required by program officers in order to check all the key parameters of this new technology. The objective of this paper is to present the global methodology and analyse data obtained on GaN technologies, simultaneously taking into account process issues, reliability concerns and microwave measurements. The originality of this work is to gather all these aspects, thanks to a new RF life test bench designed especially for GaN products. We described also failure analysis results which combine classical cross-sections and delayering, STEM and TEM observations and EBIC signatures. Finally, predictive reliability calculations for a 15 W power transistor were performed thanks to the new FIDES model and compared with manufacturer data.