Development of vertical GaN power devices

There is a strong motivation to develop GaN-based vertical Power Electronics Devices as they may allow to have a smaller footprint by one order of magnitude with respect to current SiC devices. This is of high interest for power conversion applications such as electric-vehicles, photovoltaics or UPS. Vertical GaN power devices have been developed on GaN substrates which are at the moment very expensive. GaN layers can also be grown on foreign substrates (such as Si or Sapphire). Pseudo-vertical structures have been proposed in order to contact the bottom electrode as it must be accessed on its side due to the presence of the foreign substrate. The drawback is in this case an increase of the device footprint. In order to overcome this limitation, it is proposed to use here layer transfer technologies, based on LETI’s know-how, to access the bottom electrode contact. The proposed work will first consist of defining all the technological steps necessary for the development of vertical GaN power components, and then identifying the technological blocks to be developed if necessary before setting up the complete integration. This work will build on actions already undertaken on the transfer of GaN layers. This work is financed within the electronics theme of the French PEPR (Programmes et équipements prioritaires de recherche) and of the “Programme d’investissements d’avenir du plan France Relance”. It addresses a research topic that is identified as key for the development of power electronics converters for industrial and consumer applications. It will be lead at CEA-LETI within the Minatec Campus in Grenoble.