This PhD topic is financed within the framework of the electronics section of the PEPR (Priority equipement and research programmes) and the France Relance investment programme. It adresses a research theme that has been identified as key for the development of power converters for industrial and consumer applications. It will be lead at LTM-CNRS in collaboration with CEA-LETI at the Minatec campus in Grenoble.

The work will focus on gallium nitride (GaN) power transistors which allow to implement more efficient and less cumbersome electrical converters than their widely spread silicon counterparts. At the moment, the architecture of commercial GaN devices is lateral. They have a limited power usage of several 10kW in part due to the fact that their conduction is located at the surface of the device. In the case of a vertical architecture there is instead volume conduction which allows to convert higher power densities. The development of such devices requires extensive work to study and optimize their gate module for which a sufficiently high threshold voltage, a low enough resistance (i.e. high electronic mobility) and a robustness to gate drive overvoltages are desired.