EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

With the increase of power densities in electronic packages and the requirement for miniaturisation in high power devices applied in satellites there is a strong demand for new materials which combine a high thermal conductivity and a low coefficient of thermal expansion.
A combination of metal reinforced by diamond particles allows to reduce the coefficient of thermal expansion significantly to a level of 6-10 ppm/K. At the same time thermal conductivities of >600 W/mK in Cu-diamond composites are possible to achieve and values of >800 W/mK for Ag-diamond composites. These properties are attractive for the use in Gallium Nitride wide band semiconductors used in space applications.
In order to assess the possibility for using these metal diamond composites in space application, a detailed analysis was made to assess the thermal performance when exposed to severe thermal cycling and thermal shocks. Additionally, the impact of various integration steps was simulated such as soldering and brazing processes. Following to the testing an analysis of the interfaces between the metal matrix and the diamond fillers was made.