Properties of Si–C–N films prepared on Si substrate using cobalt interfacial layers

A microwave plasma chemical vapor deposition (MPCVD) process was successfully used to synthesize Si–C–N films. The film properties were tuned by deposition parameters and engineering interfacial Co layers on Si substrates. The films were deposited by using CH4, N2, and additional solid Si columns as raw material sources. The films were characterized by scanning electron microscopy (SEM) for film morphologies, X-ray photo-emission spectroscopy (XPS) and cathodoluminescence (CL) spectroscopy for bonding structure and band gap analyses. The results show that the application of Co interlayer can have the following effects: (1) it can change film morphology from (1 0 0) preferred orientation to become pyramidal structure, and the band gap from 2.93 to 4.00 eV; (2) it may possess the additional Si(2p)–Si bonding in the films. By adding additional Si source, the atomic ratio of Si:C:N can change significantly with the decrease in carbon content of films, the film structure may vary from amorphous to crystalline and possess additional C(1s)N bonding (or N(1s)C bonding). In summary, the composition, morphology, bonding and crystal structures of Si–C–N films have been successfully demonstrated to be manipulated through applications of Co interlayer and additional Si source.