Interface features of carbon nitride films deposited on Si substrate

One kind of super-hard a-CNx film was deposited on Si substrate by the ion-beam assist magnetron sputtering. A clear interfacial layer with homogeneous thickness was found in the as-deposited film. The a-CNx layer spontaneous spalled along the interfacial defect, which indicated a high internal stress, resulting in adhesion failure. After thermal treatment, the interfacial layer between Ti layer and Si substrate seem to present a coherent or semi-coherent type with some misfit at the Si/SiOx grain boundaries. This mismatch relaxed the strain of the interface defects, and the high internal stress of the film was induced with a 3-5 atom-thick strained layer on Si substrate.