Top Heat Spreaders on GaN-based HEMT devices for improved thermal management

We report an overview of GaN-based High Electron Mobility Transistor (HEMT) thermal management by giving additional heat flow from the top of RF power devices. Different strategies have been tried by our laboratory over the years. All of them have been based on parallel microelectronic processing scheme to preserve cost and high frequency operation. In this article, we present two previous experimental results tried in the past namely with nano-crystalline diamond layers and more recently using boron nitride films. Material and electrical DC and microwave results are presented.