Ti--Al based ohmic contacts to n-type 6H-SiC with P⁺ ion implantation

The Ti--Al ohmic contact to n-type 6H-SiC has been fabricated. An array of TLM (transfer length method) test patterns with Au/Ti/Al/Ti/SiC structure is formed on N-wells created by P⁺ ion implantation into Si-faced p-type 6H-SiC epilayer. The specific contact resistance \rho_c as low as 8.64×10^-6\Omega\cdot cm² is achieved after annealing in N₂ at 900℃ for 5 min. The sheet resistance R_sh of the implanted layers is 975\Omega/\Box. X-ray diffraction (XRD) analysis shows the formation of Ti_-3SiC₂ at the metal/n-SiC interface after thermal annealing, which is responsible for the low resistance contact.