Effect of the annealing temperature on the long-term thermal stability of Pt/Si/Ta/Ti/4H-SiC contacts

The Pt/Si/Ta/Ti multilayer metal contacts on 4H-SiC are annealed in Ar atmosphere at 600 ℃-1100 ℃ by a rapid thermal processor (RTP). The long-term thermal stability is evaluated by aging the annealed contact at 600 ℃ in air. The contact's properties are determined by current-voltage measurement, and the specific contact resistance is calculated based on the transmission line model (TLM). Transmission electron microscope (TEM) and energy-dispersive x-ray spectrometry (EDX) are used to characterize the interface morphology, thickness, and composition. The results reveal that a higher annealing temperature is favorable for the formation of an Ohmic contact with a lower specific contact resistance, and causes the rapid degradation of the Ohmic contact in the aging process.