Initial stage of Cu/3C-SiC(111) interface formation at room temperature

The copper and 3C-SiC(111) junctions were fabricated at room temperature with copper films, deposited by vacuum evaporation, on substrate of 3C-SiC(111) films, grown by molecular beam epitaxy (MBE). The interfacial microstructures and stoichiometrics in the initial stage of the Cu/3CSiC interface formation were characterized with synchrotron radiation photoelectron spectroscopy (SRPES) and X-ray photoelectron spectroscopy (XPS). The results show that the Cu coverage significantly affects the various factors, including the surface states of the SiC, the Cu film growth modes, Schottky barrier heights, the binding energy and the band bending. For instance, as the coverage of Cu increases from 0.08ML(monolayer) to 2.0ML, the XPS peak position of Cu2P3/2 shifts from 933.1 eV to 932.8 eV. And the peak of the kinetic energy of Si2p core level in the SRPES spectra moves from 43.55 eV to 43.87 eV, when at Cu coverage changes from 0.0 ML to 2.0 ML. The fairly stable, unchanged peak shapes show no distinctive chemical reaction of Cu and the substrate. Moreover, we found that the 2D growth mode of Cu films changes into 3D growth mode at a Cu critical coverage of 0.1 ML. Besides, all the surface states of SiC vanish instantly after the Cu deposition starts. Interesting finding is that as Cu films grow, the valence band (VB) bends, and Schottky barrier height rises up, 2eV at a Cu coverage of 2.0 ML.