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

Abstract

ABSTRACTThe growth kinetics of thermally stable Ti(100nm)/TaSi2 (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 TaSi2 decomposition. The second is titanium silicide formation adjacent to the decomposed TaSi2. The third is pseudo-epitaxial Ti5Si3 at the SiC interface. Specific contact resistance values ranging from 10−4–10−6 Ω-cm2, remained stable after 200 hours at 600°C in air. Activation energies of 1.03eV for platinum silicide oxidation and 1.96eV for Ti5Si3 are obtained from Arrhenius plots.