Reaction Kinetics of Thermally Stable Contact Metallization on 6H-SiC

The growth kinetics of thermally stable Ti(100nm)/TaSi 2 (200nm)/Pt (300nm) metallization on 6H-SiC was studied after heat treatment in air up to 700°C. Scanning electron microscopy (SEM) of the contact surface morphology reveals a two-dimensional network of features that is attributed to non-uniform oxide growth associated with the multigrain structure of the platinum overlayer. Auger electron spectroscopy (AES) and high-resolution transmission electron microscopy (HRTEM) identified three important reaction zones after initial 30-minute anneal at 600°C in nitrogen. One is the formation of a platinum silicide overlayer resulting from TaSi 2 decomposition. The second is titanium silicide formation adjacent to the decomposed TaSi2. The third is pseudo-epitaxial Ti 5 Si 3 at the SiC interface. Specific contact resistance values ranging from 10 −4 –10 −6 Ω-cm 2 , remained stable after 200 hours at 600°C in air. Activation energies of 1.03eV for platinum silicide oxidation and 1.96eV for Ti 5 Si 3 are obtained from Arrhenius plots.