Ti Ohmic contact without post-annealing process to n-type 6H-SiC

Ohmic contacts onto 6H-SiC without post-annealing were achieved by releasing the Fermi level from pinning and also by selecting Ti and Al with low work functions as contact metals, thereby reducing Schottky barriers to zero. To release it from the pinning, we utilized surface treatments consisting of the oxidation followed by HF etching process to remove imperfect surface layer and the wet chemical Contact resistivities rho(c), around 1x10(-2) Omega cm(2) lightly doped SIC substrates with a carrier concentration N-D similar to 2x10(17) cm(-3). Since no heat treatments to electrodes were performed throughout the experiments, the electrodes surfaces were kept flat and the metal electrodes were homogenious.