Ti–Ni ohmic contacts on 3C–SiC doped by nitrogen or phosphorus implantation

For electronic devices, good ohmic contacts are required. To achieve such contacts, the semiconductor layer has to be highly doped. The only method available to locally dope the SiC is to implant dopants in the epilayer through a mask. In this work, non-intentionally doped 3C–SiC epilayers were implanted using nitrogen or phosphorus at different energies and subsequently annealed at temperatures between 1150 °C and 1350 °C in order to form n+ implanted layers. Different techniques such as Fourier Transformed InfraRed spectroscopy (FTIR), Secondary Ion Mass Spectroscopy (SIMS) and Transmission Electron Microscopy (TEM) were used to characterize implanted 3C–SiC epilayers subsequently to the different annealing steps. Then, Ti–Ni contacts were carried out and the specific contact resistance (ρC) was determined by using circular Transfer Length Method (c-TLM) patterns. ρC values were investigated as a function of implanted species and contact annealing conditions, and compared to those obtained for highly doped 3C–SiC epilayers. As expected, ρC value is highly sensitive to post-implantation annealing. This work demonstrates that low resistance values can be achieved using nitrogen or phosphorus implantation at room temperature hence enabling device processing.