Very high temperature (800°C) ohmic contact of Au/Ni2Si on n-type polycrystalline silicon carbide aged in air

Ohmic and low-resistance electrical contacts on silicon carbide have been demonstrated for the first time up to very high temperature (800°C) in an oxidizing environment. A specific contact resistance of about 2 × 10^-4 Ω.cm² was achieved after silicidation at 900°C. Long term aging tests in an oxygen atmosphere were performed, demonstrating ohmic behavior up to 1000 h at 550°C and over 4 h at 800°C. The aging mechanism has been explained, suggesting that polycrystalline 3C-SiC is not as stable as expected at very high temperatures, acting as a source for Si out-diffusion. Also, in-situ electrical measurements at very high temperatures in air using the transmission line method (L-TLM) have been achieved demonstrating good performance of the proposed metallization at representative operating conditions for harsh environments.