Optimised thermal and microwave packaging for wide-band gap transistors: diamond & flip chip

Wide-band gap (WBG) transistors give a real breakthrough for power devices compared to silicon (Si) and gallium arsenide (GaAs) components. However, for space applications, the high power density of WBG transistors makes the thermal management critical and requires thermal investigations. Some packaging solutions dedicated to those power transistors are presented in this paper. The focus is made on diamond-based packaging with two topologies. In the first one, the die is soldered on a diamond carrier. In the second one, it is flip chip bonded on a diamond circuit. Thermal simulations, thermal cycling and electrical measurement results are given for both configurations.