Photoelectron Spectroscopic Insights Into Interfacial Silicide Formation and Electronic Coupling Governing Contact...

Silicon carbide (SiC) is a leading candidate for next-generation power electronics. However, achieving reliable and low-resistance metal/SiC contacts remains a challenge due to incomplete mechanistic understanding of the interplay between interfacial chemistry, electronic structure, and contact resistance. Here, we combine laboratory-based and synchrotron-based photoelectron spectroscopy (PES) to elucidate the evolution of the molybdenum (Mo)/4H-SiC(0001) interface under different fabrication pathways. Distinct spectral features reveal Mo silicide (MoSi_x) formation after annealing and demonstrate that direct Mo deposition on heated 4H-SiC(0001) substrates enhances MoSi_x formation and yields a cleaner, more homogeneous interface, owing to altered Mo growth dynamics at elevated substrate temperatures. This interfacial MoSi_x layer strengthens electronic coupling and optimizes band alignment across the Mo/SiC junction, achieving authentic Ohmic contact with a tenfold reduction in contact resistance. These findings elucidate the electronic and chemical origins of low-barrier Mo/SiC contacts, offering a practical, energy-efficient route towards low-resistance SiC-based devices.