Graphene as a diffusion barrier for Al and Ni/Au contacts on silicon

The insertion of chemically vapor deposited graphene layers between Al metallization and Si substrates and between Au and Ni metal layers on Si substrates is shown to provide a significant reduction in spiking and intermixing of the metal contacts and reaction with the Si, where the bilayer graphene was transferred to the samples after the Cu-foil was etched. The graphene prevents reaction between Al and Si up to the temperatures of 700 degrees C and the intermixing of Au and Ni up to the temperatures of at least 600 degrees C. The outstanding performance of the graphene as a metal diffusion barrier will be very useful to improve the stability of the metallizations at elevated temperatures. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.3701711]