Thermal degradation of Au/Ni2Si/n-SiC ohmic contacts under different conditions

The thermal degradation of Au/Ni2Si/n-SiC ohmic contact was investigated after long-time aging in air at 400 °C or rapid thermal annealing in Ar up to 700 °C. Current–voltage characteristics, sheet resistance measurements, Rutherford backscattering spectrometry, X-ray diffraction and scanning electron microscopy were used to characterize the contacts before and after heat treatments. Thermal stress at different conditions shows different influence on the properties degradation of Au/Ni2Si/n-SiC ohmic contacts. It is shown that aging of the contacts in air at 400 °C resulted in complete degradation due to both oxygen penetration and inter-diffusion/reaction processes at the metal/SiC interface. In contrast, only a small change in contact morphology was detected on the contacts annealed in Ar at 700 °C.